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1
Petrov, Ryan. "The microclimate of Australian cattle feedlots." University of Southern Queensland, Faculty of Engineering and Surveying, 2007. http://eprints.usq.edu.au/archive/00003191/.
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[Abstract]: The incidence of cattle heat stress is a significant production and welfare issue for the feedlot industry. It is hypothesised that the presence and physical nature of feedlots causes significant microclimatic variations compared to the external environment.In order to test this hypothesis, data was collected using a series of automatic weather stations located in the external environment surrounding two Australian feedlots. Comparison of this data with regional Bureau of Meteorology sites was undertaken to verify the quality of these ‘control’ sites. To determine the climate within the feedlot separate automatic weather stations were placed within the cattle pens at each site, with one station located in an unshaded pen and one directly under an artificial shade structure within an adjacent pen.This dissertation reports the collection and analyses of detailed climatic data from the surrounds and within the cattle pens of these two Australian feedlots. The project also sought to determine microclimatic differences within the feedlot pen area that may be caused by the presence of the shade structures.It was found that the presence of a feedlot does create significant microclimatic variations. Specifically, it was determined that the albedo values of the feedlot pen surface are significantly lower (ranging from 0.13 to 0.19) than those of the external feedlot environment (typically 0.15 to 0.25). This is a result of the surface changes arising from the establishment of clay based manure covered pens. Under wet conditions the differences in albedo values were further increased. It was found that the short wave radiation reflection from the external feedlot environment was 4% greater than that from the unshaded feedlot pen surfaces under dry conditions and 10% greater under wet conditions. The increased adsorption of solar radiation by the feedlot pen surface created ground temperatures that were on average 2 to 4°C warmer than those of the feedlot surrounds. The re-radiation of heat from the pen surface was found to create warmer air temperatures within the feedlot pens compared to the external environment, particularly overnight. Between the hours of 4am to 6am it was found that on average the air temperatures of the shaded and unshaded feedlot pens were 0.7°C and 0.5°C warmer than the external feedlot environment.It was found that feedlot pen infrastructure and cattle significantly reduce wind speeds under a height of 10 metres. The average 2 metre wind speeds of the external feedlot environments were found to be 29% and 9% higher than those recorded in the unshaded pens at the northern and southern feedlots respectively.Shade structures within feedlot pens were found to be effective in reducing incoming solar radiation with the galvanised sheeting reducing incoming solar radiation by 76% and the shade cloth providing a 72% reduction. These reductions provided both lower ground temperatures and a significant reduction in radiant heat loads under the shade. It was determined that the environment under shade structures was more humid compared to that of the unshaded pens with humidity levels recorded being 8 to 12% higher. Shade structures also restrict horizontal wind movement with the 2 metre wind speeds in the shaded pens being on average 11% and 0.5% lower than those recorded in the unshaded pens for the Queensland and NSW feedlots respectively.Research has shown that microclimatic variations such as increased air temperatures, increased humidity and restricted air movement can have an adverse effect on cattle health. It is concluded from this project that in order to mitigate these effects a number of feedlot design concepts be implemented, and management practices should be adopted. Maintaining minimal quantities of manure on the pen surface will provide lower ground temperatures, dryer pen conditions and inhibit the re-radiation of heat and evapotranspiration from the pen surface. Adequate air flow should be maintained by siting feedlots in areas of suitable topography, and designing feedlot infrastructure and shade structures to maximise air movement. Shade structures need to aim at providing dryer pen surfaces to minimise humidity levels. Incorporation of these recommendations into feedlot design and management will assist in optimising the feedlot microclimate.
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Baum, Kristen A. "Air emissions measurements at cattle feedlots." Thesis, Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/775.
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Ungkuraphinunt, Paphapit. "Factors contributing to the presence of Escherichia coli O157:H7 and O157:NM in feedlots and feedlot cattle." Texas A&M University, 2003. http://hdl.handle.net/1969.1/1172.
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Environmental sources within 5 feedlots were sampled for E. coli O157:H7 and O157:NM to determine the prevalence of this pathogen with a view to minimize or control its spread in the feedlot environment. Monthly samples were taken from the feedlots in the Panhandle and South Plains of Texas over a nine-month period. Samples were examined by an immunomagnetic bead separation, followed by plating onto CT-SMAC and CHROMagar O157 media. Sorbitol-negative colonies were tested using ImmunoCard Stat! E. coli O157:H7 Plus and confirmed as E. coli O157:H7, using biochemical (Vitek system) and serological tests (latex agglutination). Additionally, one hundred sponge samples were collected from the hides of stunned cattle at the slaughter plant. All isolates were subjected to rep-PCR DNA fingerprinting and antimicrobial profiling.
E. coli O157 was isolated from hide (56%) and environmental samples (4%). E. coli O157 was isolated from all environmental sources, with peak prevalence during November (9%) and March (10%). At least one sample from each feedlot was positive 42% of the time. The most contaminated sites were the chute area (6%) and sludge from waste water ponds (6%). Positive samples were most frequently found from feedlot 5 (7%) and the greatest variation in positive samples between feedlots (0-34%) occurred during March. A decrease in the presence of E. coli O157 in feedlots was observed during January (0%), when ambient, water, and pond sludge temperatures were consistently low. No correlation with other environmental factors was observed. Hide was a primary source of E. coli O157 on carcasses with an overall prevalence of 56%. Of two sampling days, the number of positive hide samples varied from 14% for the first day to 98% for the second day. The total positive samples collected (environmental (47); hide (56)) were 64% H7, and 36% NM. The environmental isolates showed similar antibiotic resistance patterns, regardless of the source. Most E. coli O157 isolates from the feedlots and hides showed a high level of resistance to cephalothin (45%) and sulfisoxazole (56%). E. coli O157 isolates from feedlots were resistant to more than 10 antibiotics (9/317). All of the isolates appeared highly similar, with an average similarity of 53% by rep-PCR DNA fingerprinting.
4
Vaillant, Grace C. "Nutrient cycling at cattle feedlots field & laboratory study." Thesis, Manhattan, Kan. : Kansas State University, 2007. http://hdl.handle.net/2097/318.
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Bonifacio, Henry F. "Estimating particulate emission rates from large beef cattle feedlots." Diss., Kansas State University, 2013. http://hdl.handle.net/2097/15530.
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Doctor of PhilosophyDepartment of Biological and Agricultural Engineering
Ronaldo G. Maghirang
Emission of particulate matter (PM) and various gases from open-lot beef cattle feedlots is becoming a concern because of the adverse effects on human health and the environment; however, scientific information on feedlot emissions is limited. This research was conducted to estimate emission rates of PM[subscript]10 from large cattle feedlots. Specific objectives were to: (1) determine feedlot PM[subscript]10 emission rates by reverse dispersion modeling using AERMOD; (2) compare AERMOD and WindTrax in terms of their predicted concentrations and back-calculated PM[subscript]10 emission rates; (3) examine the sensitivity of both AERMOD and WindTrax to changes in meteorological parameters, source location, and receptor location; (4) determine feedlot PM[subscript]10 emission rates using the flux-gradient technique; and (5) compare AERMOD and computational fluid dynamics (CFD) in simulating particulate dispersion from an area source. PM[subscript]10 emission rates from two cattle feedlots in Kansas were determined by reverse dispersion modeling with AERMOD using PM[subscript]10 concentration and meteorological measurements over a 2-yr period. PM[subscript]10 emission rates for these feedlots varied seasonally, with overall medians of 1.60 and 1.10 g /m[superscript]2 -day. Warm and prolonged dry periods had significantly higher PM emissions compared to cold periods. Results also showed that the PM[subscript]10 emissions had a diurnal trend; highest PM[subscript]10 emission rates were observed during the afternoon and early evening periods. Using particulate concentration and meteorological measurements from a third cattle feedlot, PM[subscript]10 emission rates were back-calculated with AERMOD and WindTrax. Higher PM[subscript]10 emission rates were calculated by AERMOD, but their resulting PM[subscript]10 emission rates were highly linear (R[superscript]2 > 0.88). As such, development of conversion factors between these two models is feasible. AERMOD and WindTrax were also compared based on their sensitivity to changes in meteorological parameters and source locations. In general, AERMOD calculated lower concentrations than WindTrax; however, the two models responded similarly to changes in wind speed, surface roughness, atmospheric stability, and source and receptor locations. The flux-gradient technique also estimated PM[subscript]10 emission rates at the third cattle feedlot. Analyses of PM[subscript]10 emission rates and meteorological parameters indicated that PM[subscript]10 emissions at the feedlot were influenced by friction velocity, sensible heat flux, temperature, and surface roughness. Based on pen surface water content measurements, a water content of at least 20% (wet basis) significantly lowered PM[subscript]10 emissions at the feedlot. The dispersion of particulate from a simulated feedlot pen was predicted using CFD turbulence model ([kappa]-[epsilon] model) and AERMOD. Compared to CFD, AERMOD responded differently to wind speed setting, and was not able to provide detailed vertical concentration profiles such that the vertical concentration gradients at the first few meters from the ground were negligible. This demonstrates some limitations of AERMOD in simulating dispersion for area sources such as cattle feedlots and suggests the need to further evaluate its performance for area source modeling.
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Alkire, Deke Omar Kerley Monty Stephen. "The effects of supplemental rumen-protected fat in feedlot rations." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/5953.
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Thesis (Ph. D.)--University of Missouri-Columbia, 2007.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on March 20, 2009) Vita. Includes bibliographical references.
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Michels, Cherie Dawn. "Bioaerosol levels at feedlots and an indoor wastewater treatment headworks." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq65160.pdf.
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Dokuparti, Santosh. "Development and demonstration of coal combustion byproducts based cattle feedlots /." Available to subscribers only, 2006. http://proquest.umi.com/pqdweb?did=1136092441&sid=24&Fmt=2&clientId=1509&RQT=309&VName=PQD.
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Babcock, Abram Heath. "Epidemiology of bovine respiratory disease and mortality in commercial feedlots." Diss., Kansas State University, 2010. http://hdl.handle.net/2097/4483.
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Doctor of PhilosophyDepartment of Diagnostic Medicine/Pathobiology
David G. Renter
Bradley J. White
The objective of my research was to quantify epidemiologic parameters associated with feedlot mortality and bovine respiratory disease complex (BRDC); the most significant cause of morbidity in U.S. feeder cattle. We conducted four retrospective studies utilizing individual health and cumulative cohort-level feedlot data. We developed a database that represented 33 U.S. feedlots from six states over ten years. Each project used a subset of these data. We found that the timing of BRDC was associated with important performance and health indices. In the first study, we evaluated the effect of the timing of individual BRDC treatments on standardized net returns. We found important performance and health measures (e.g. hot carcass weight and number treatments) driving net return differences associated with the timing of BRDC. For the second cohort-level study, we classified temporal patterns of BRDC, and evaluated associations among temporal patterns and performance and health. Temporal patterns were significantly associated with mean daily weight gain, days on feed, carcass weight, yield grade, quality grade, cumulative mortality, and retreatment risk. We also evaluated combined mortality and culling risks and quantified the effects of risk factors using count models. All risk factors (arrival weight, gender, and arrival month) were significant and the effects were modified by one another; effects of these covariate patterns have been impossible to quantify in smaller studies. Finally, we assessed the ability of regression models to predict cumulative BRDC morbidity based on arrival risk factors; then assessed the additional value of incorporating daily BRDC morbidity and mortality information. The percent of correctly classified cohorts did increase across days, but the effect of day was modified by weight, month, and feedlot. Information on daily morbidity was beneficial in predicting cumulative morbidity, but daily mortality provided little benefit. Our database containing animal health and cohort-level data allowed us to generate novel information on the effects of the timing of BRDC in feedlot populations. We also demonstrated effects of covariate patterns on adverse health outcomes that heretofore had been difficult to quantify. Finally, we showed that a predictive model for BRDC may be useful for the feedlot industry; this model should be further developed with future research.
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Bonifacio, Henry F. "Particulate matter emissions from commercial beef cattle feedlots in Kansas." Thesis, Manhattan, Kan. : Kansas State University, 2009. http://hdl.handle.net/2097/2325.
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Kolath, William H. Kerley Monty Stephen. "The relationship between mitochondria and residual feed intake in feedlot cattle." Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/4368.
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Thesis (Ph.D.)--University of Missouri-Columbia, 2006.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on April 27, 2009) Vita. Includes bibliographical references.
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Stockman, Catherine Ann. "The physiological and behavioural responses of sheep exposed to heat load within intensive sheep industries." Thesis, Stockman, Catherine Ann (2006) The physiological and behavioural responses of sheep exposed to heat load within intensive sheep industries. PhD thesis, Murdoch University, 2006. https://researchrepository.murdoch.edu.au/id/eprint/437/.
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The live export and feedlotting industries are the major intensive sheep industries in Australia. During live shipment, sheep are exposed to prolonged periods of high heat and humidity, with little relief for several days, while environmental conditions in a Western Australian sheep feedlot have not yet been assessed. The research described in this thesis was conducted to determine the physiological responses of sheep to conditions within the live export and feedlotting industries, with particular focus on that of heat stress.
Merino wethers and Awassi rams developed significant change in physiological variables when exposed to prolonged periods of high heat and humidity, such as during long haul, live export voyages to the Northern Hemisphere. Physiological changes such as increased core temperature, respiratory rate, panting score and associated changes in blood gas variables were apparent in Merino wethers. However, Awassi rams showed exceptional ability to maintain homeostasis under the same environmental conditions, with no significant changes in core temperature and only slight alteration in blood gas variables. Results from this study indicated that electrolyte supplementation of sheep during live export would not be warranted because plasma electrolytes did not drastically change and blood gas variables quickly returned to normal following the heat.
Further studies developed methods to determine the critical wet bulb temperature, otherwise known as the heat stress threshold (HST) of Merino rams, ram lambs and wethers exposed to live export conditions. These studies found that ram lambs had a lower HST than both adult rams and wethers. However, both adult rams and wethers had a similar HST. Heat stress thresholds determined from these studies have been used in a model to predict high risk shipments for particular classes of sheep (Stacey 2003).
This thesis also details the environmental conditions within a Western Australian summer feedlot and the physiological responses of cross bred ewes and wethers to these conditions when fed feedlot rations. This study found that temperatures in a typical Western Australian feedlot in summer increased above 40 degrees C with low humidity; however, temperatures generally decreased to be within the sheep's thermoneutral zone at night. Both ewes and wethers had significantly increased core temperatures in response to these conditions, with sheep spending significantly more time in the shade than in the sun during the day. Both ewes and wethers had increased respiratory rates and panting scores during an intensive climate room experiment with similar environmental conditions. However, feed intake did not decrease even when climate room temperatures increased at night and humidity levels were higher than that found in typical feedlot conditions in Western Australia.
Work completed within this thesis has led to a greater understanding of the physiological responses of sheep to prolonged and continuous high heat such as during live export and to conditions of a typical Western Australian summer feedlot. This research has set a foundation for further study of management of sheep during live export and feedlotting.
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Stockman, Catherine Ann. "The physiological and behavioural responses of sheep exposed to heat load within intensive sheep industries." Stockman, Catherine Ann (2006) The physiological and behavioural responses of sheep exposed to heat load within intensive sheep industries. PhD thesis, Murdoch University, 2006. http://researchrepository.murdoch.edu.au/437/.
Full textAbstract:
The live export and feedlotting industries are the major intensive sheep industries in Australia. During live shipment, sheep are exposed to prolonged periods of high heat and humidity, with little relief for several days, while environmental conditions in a Western Australian sheep feedlot have not yet been assessed. The research described in this thesis was conducted to determine the physiological responses of sheep to conditions within the live export and feedlotting industries, with particular focus on that of heat stress.
Merino wethers and Awassi rams developed significant change in physiological variables when exposed to prolonged periods of high heat and humidity, such as during long haul, live export voyages to the Northern Hemisphere. Physiological changes such as increased core temperature, respiratory rate, panting score and associated changes in blood gas variables were apparent in Merino wethers. However, Awassi rams showed exceptional ability to maintain homeostasis under the same environmental conditions, with no significant changes in core temperature and only slight alteration in blood gas variables. Results from this study indicated that electrolyte supplementation of sheep during live export would not be warranted because plasma electrolytes did not drastically change and blood gas variables quickly returned to normal following the heat.
Further studies developed methods to determine the critical wet bulb temperature, otherwise known as the heat stress threshold (HST) of Merino rams, ram lambs and wethers exposed to live export conditions. These studies found that ram lambs had a lower HST than both adult rams and wethers. However, both adult rams and wethers had a similar HST. Heat stress thresholds determined from these studies have been used in a model to predict high risk shipments for particular classes of sheep (Stacey 2003).
This thesis also details the environmental conditions within a Western Australian summer feedlot and the physiological responses of cross bred ewes and wethers to these conditions when fed feedlot rations. This study found that temperatures in a typical Western Australian feedlot in summer increased above 40 degrees C with low humidity; however, temperatures generally decreased to be within the sheep's thermoneutral zone at night. Both ewes and wethers had significantly increased core temperatures in response to these conditions, with sheep spending significantly more time in the shade than in the sun during the day. Both ewes and wethers had increased respiratory rates and panting scores during an intensive climate room experiment with similar environmental conditions. However, feed intake did not decrease even when climate room temperatures increased at night and humidity levels were higher than that found in typical feedlot conditions in Western Australia.
Work completed within this thesis has led to a greater understanding of the physiological responses of sheep to prolonged and continuous high heat such as during live export and to conditions of a typical Western Australian summer feedlot. This research has set a foundation for further study of management of sheep during live export and feedlotting.
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Guo, Li. "Measurement and control of particulate emissions from cattle feedlots in Kansas." Diss., Kansas State University, 2011. http://hdl.handle.net/2097/8549.
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Doctor of PhilosophyDepartment of Biological & Agricultural Engineering
Ronaldo G. Maghirang
Emissions of particulate matter (PM) are an increasing concern for large open beef cattle feedlots. Research is needed to develop science-based information on PM emissions and abatement measures for mitigating those emissions. This research was conducted to (1) measure PM concentrations emitted from large cattle feedlots, (2) compare different samplers for measuring concentrations of PM with equivalent aerodynamic diameter of 10 µm or less (PM10), (3) evaluate the relative effectiveness of pen surface treatments in reducing PM10 emissions, and (4) predict PM control efficiency of vegetative barriers. Concentrations of PM with equivalent aerodynamic diameter of 2.5 µm or less (PM2.5), PM10, and total suspended particulates (TSP) upwind and downwind of two large cattle feedlots (KS1, KS2) in Kansas were measured with gravimetric samplers. The downwind and net concentrations generally decreased with increasing water content (WC) of the pen surface; for effective control of PM emissions from feedlots, it appears that pen surface WC should be at least 20% (wet basis). Three types of samplers for measuring PM10 concentrations in feedlots KS1 and KS2 were compared: Tapered Element Oscillating Microbalance™ (TEOM), high-volume (HV), and low-volume (LV) PM10 samplers. Measured PM10 concentration was generally largest with the TEOM PM10 sampler and smallest with the LV PM10 sampler. A laboratory apparatus was developed for measuring the PM10 emission potential of pen surfaces as affected by surface treatments. The apparatus was equipped with a simulated pen surface, mock cattle hooves that moved horizontally across the pen surface, and PM10 samplers that collected emitted PM10. Of the surface treatments evaluated, application of water (6.4 mm) and hay (723 g/m2) exhibited the greatest percentage reduction in PM10 emission potential (69% and 77%, respectively) compared with the untreated manure layer. Computational fluid dynamics (CFD) was applied to predict airflow and particle collection by a row of trees (2.2 m high × 1.6 m wide). Predicted particle collection efficiencies generally agreed with published data and ranged from less than 1% for 0.875-µm particles to approximately 32% for 15-µm particles.
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Aguilar, Gallardo Orlando Alexis. "Measurement and control of greenhouse gas emissions from beef cattle feedlots." Diss., Kansas State University, 2012. http://hdl.handle.net/2097/15167.
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Doctor of PhilosophyDepartment of Biological and Agricultural Engineering
Ronaldo Maghirang
Emission of greenhouse gases (GHGs), including nitrous oxide (N2O), methane (CH4), and carbon dioxide (CO2), from open beef cattle feedlots is becoming an environmental concern; however, scientific information on emissions and abatement measures for feedlots is limited. This research was conducted to quantify GHG emissions from feedlots and evaluate abatement measures for mitigating emissions. Specific objectives were to: (1) measure N2O emissions from the pens in a commercial cattle feedlot; (2) evaluate the effectiveness of surface amendments in mitigating GHG emissions from feedlot manure; (3) evaluate the effects of water application on GHG emissions from feedlot manure; and (4) compare the photo-acoustic infrared multi-gas analyzer (PIMA) and gas chromatograph (GC) in measuring concentrations of N2O and CO2 emitted from feedlot manure. Field measurements on a commercial beef cattle feedlot using static flux chambers combined with GC indicated that N2O emission fluxes varied significantly with pen surface condition. The moist/muddy surface had the largest median emission flux; the dry and compacted, dry and loose, and flooded surfaces had significantly lower median emission fluxes. Pen surface amendments (i.e., organic residues, biochar, and activated carbon) were applied on feedlot manure samples in glass containers and evaluated for their effectiveness in mitigating GHG emissions. Emission fluxes were measured with the PIMA. For dry manure, all amendments showed significant reduction in N2O and CO2 emission fluxes compared with the control (i.e., no amendment). For moist manure, biochar significantly reduced GHG emissions at days 10 and 15 after application; the other amendments had limited effects on GHG emissions. The effect of water application on GHG emissions from feedlot manure was evaluated. Manure samples (with and without water application) were placed in glass containers and analyzed for GHG emission using a PIMA. For the dry manure, GHG emissions were negligible. Application of water on the manure samples resulted in short-term peaks of GHG emissions a few minutes after water application. Comparison of the GC and PIMA showed that they were significantly correlated but differed in measured concentrations of N2O and CO2. The PIMA showed generally lower N2O concentrations and higher CO2 concentrations than the GC.
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Flint, Mark-Shannon. "Strategies and techniques to successfully feedlot goats (Capra hircus) in a commercial system /." [St. Lucia, Qld.], 2006. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe19203.pdf.
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Pugh, Jamie A. "Prediction of optimal rumen degradable protein levels in no-roughage, corn-based feedlot diets." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/6277.
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Thesis (M.S.)--University of Missouri-Columbia, 2007.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on January 16, 2008) Includes bibliographical references.
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Terrell, Shane Patrick. "Feedlot lameness: industry perceptions, locomotion scoring, lameness morbidity, and association of locomotion score and diagnosis with case outcome in beef cattle in Great Plains feedlots." Diss., Kansas State University, 2016. http://hdl.handle.net/2097/34470.
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Doctor of PhilosophyDepartment of Diagnostic Medicine/Pathobiology
Daniel U. Thomson
In current literature, there is a limited amount of large scale data available demonstrating lameness morbidity in beef cattle feedlots, the subsequent outcomes of individuals exhibiting lameness, the morbidity and mortality of various lameness diagnoses, or the effect of locomotion score at the time of first morbidity and its effect on outcome. In addition, current perceptions of lameness by feedlot industry participants are not known and a reliable locomotion scoring system fit for use in a feedlot setting has not been developed. Consequently, the objectives of this research were three-fold. First, to obtain a baseline of the perception of lameness within the feedlot industry. Second, to develop a functional locomotion scoring system for use in feedlots and to test a training program implementing this locomotion scoring system for inter-rater reliability. Third, determine the association of lameness diagnosis and locomotion score at time of initial lameness diagnosis with case outcome in feedlot cattle and provide beef cattle feedlot lameness morbidity, mortality, and realizer incidence rates due to different lameness etiologies in a large scale, multisite study. One hundred forty-seven consulting nutritionists, veterinarians, and feedlot managers participated in the feedlot cattle lameness survey. The median response of estimated lameness incidence in the feedyard was 2%, with a mode of 1% and a mean of 3.8%. Participants indicated that footrot, injury, and toe abscesses were the most common causes of lameness. A locomotion scoring system was developed to clinically assess locomotion of beef cattle. The scoring system consisted of 4 categories: normal movement (0), slightly affected gait (1), obviously shortened stride or bobbing of head (2), and reluctance to move or apply weight to the limb while walking or standing (3). A total of 50 commercial feedlot employees and agricultural students were trained to use the scoring system in either English or Spanish. The scoring system was tested for inter-rater agreement and rater agreement against a cooperative standard based on consensus score by a team of individuals involved in the development of the scoring system, which included beef cattle veterinarians and welfare experts. Intra-class correlation coefficient (ICC) and Fleiss’s kappa were used to evaluate inter-rater agreement and rater agreement against the cooperative standard. Inter-rater agreement using ICC was 0.85 (95% CI; 0.75 to 0.93) while the mean kappa value was 0.52 (moderate agreement). Rater agreement with the cooperative standard resulted in mean kappa value of 0.64 (substantial agreement). A dynamic population longitudinal study with an initial study population of 245,494 head of feedlot cattle, with 524,780 animal arrivals and 527,220 animal departures recorded over the 12-month study was conducted over a year by trained personnel in six participating feedlots located in Kansas and Nebraska. Lameness morbidity incidence was 1.04 cases per 100 animal-years; lameness mortality was 0.397 cases per 100 animal-years. Cattle locomotion score (LMS; scale of 0 to 3 at time of initial diagnosis) were LMS1(22% of lameness cases), LMS2 (31%), and LMS3(22%). 24% of the lameness cases were not assigned a locomotion score (NS). Mortality risks were greatest for LMS3 (33.0%) and NS (31.3%), and were least for LMS1 (10.0%) with LMS2 (19.1%) being intermediate (P < 0.05).
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Lehmkuhler, Jeffrey W. "Feedlot cattle responses to ruminally undegradable protein /." free to MU campus, to others for purchase, 2001. http://wwwlib.umi.com/cr/mo/fullcit?p3036841.
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Andersen, Daniel Steven. "Modeling the performance of runoff control systems on open beef feedlots in Iowa." [Ames, Iowa : Iowa State University], 2008.
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Kline, Terence Raymond. "ENVIRONMENTAL FACTORS AFFECTING ENERGETIC EFFICIENCY OF FEEDLOT CATTLE IN THE SOUTHWESTERN UNITED STATES (CALIFORNIA)." Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275359.
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Shae, BillieJo Mae Armbrust. "Effects of Winter Weather Risk on the Profitability of Beef Feedlots in North Dakota." Thesis, North Dakota State University, 2012. https://hdl.handle.net/10365/26677.
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This study examines the effects of management decisions, animal performance, weather risk, and economic variables on the profitability of the beef feedlot in North Dakota using data from the Dakota Feeder Calf Show and feed trials at North Dakota State University's Carrington Research and Extension Center. The effects of these variables were studied using an ordinary least squares analysis. Results demonstrated that severe cold stress reduced the profits of the feedlot in North Dakota. Results suggest that steers placed during the fall in North Dakota with placement weights > 600 pounds are more profitable to feed than lighter weight steers.State Board of Agricultural Research and Education (SBARE)
State of North Dakota
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Luseba, Dibungi. "The effect of selenium and chromium on stress level, growth performance, selected carcass characteristics and mineral status of feedlot cattle." Pretoria : [s.n.], 2002. http://explore.up.ac.za/record=b1545209.
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Melo, Verônica Freitas de Paula. "Silagens de milho consorciado com forrageira tropical e leguminosa em dietas para terminação de cordeiros /." Ilha Solteira, 2016. http://hdl.handle.net/11449/134251.
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Orientador: Rafael Silvio Bonilha PinheiroBanca: Viviane Correira Santos
Banca: Jane Maria Bertocco Ezequiel
Resumo: A produção de volumosos para a alimentação animal através do sistema de integração lavoura-pecuária é uma alternativa para a recuperação de pastagens degradadas e para a produção de volumosos conservados de alta qualidade. Neste sistema, o consorcio de gramíneas com leguminosas pode ser uma estratégia para a produção de silagem, pois a fixação biológica de nitrogênio incrementa os teores e a disponibilidade desse nutriente no solo, consequentemente, melhorando o valor nutricional da silagem. Pesquisas em busca de alternativas para volumosos de melhor qualidade são fundamentais para a eficiência dos sistemas de produção de cordeiros, principalmente para o confinamento, pois a alimentação representa o maior custo neste sistema. O presente trabalho teve o objetivo de avaliar o efeito de volumosos, provindo de um sistema de integração lavoura-pecuária, sobre o desempenho, digestibilidade, produção de metano e dióxido de carbono entérico, comportamento ingestivo e a análise de custos da terminação de cordeiros ½ Dorper e ½ Santa Inês em confinamento, com dietas contendo concentrado e diferentes silagens (silagem de milho exclusivo, silagem de milho + Urochloa brizantha cv. Marandu e silagem de milho + Urochloa brizantha cv. Marandu + guandu-anão). O ganho médio diário (kg/dia), assim como o período em que os cordeiros permaneceram confinados, não foi influenciado pelas diferentes dietas. A utilização da silagem proveniente do consórcio do milho, Marandu e guandu-anão na dieta de cordeiros, proporcionou aumento no consumo de matéria seca (kg/dia) e acresceram os tempos dispendidos para ruminação, mastigação e distribuição da fibra fisicamente efetiva. As dietas mostraram rentabilidade favorável na terminação de cordeiros em confinamento; entretanto, o maior retorno econômico foi obtido com o sistema em que os animais foram alimentados com silagem...
Abstract: The production of forage to the feeding through the integrated crop-livestock system (ILP) is an alternative for the recovery of degraded pastures and the production of silage high quality. The consortium of grasses with legumes can be a strategy for the production of silage because the biological nitrogen fixation increases the levels and the availability of this nutrient in the soil, thus improving the nutritional value of the silage. Research in search of alternatives to bulky best quality are fundamental to the efficiency of sheep production systems, primarily for the confinement because food represents the largest cost in this system. The aimed of this study was to evaluate the effect of silage, coming from a crop-livestock integration system on performance, digestibility, production of CH4 and CO2 in vitro, feeding behavior and cost analysis termination lambs ½ Dorper ½ Santa Inês in feedlot, with diets consist of concentrated and different silages (corn silage; corn silage + Urochloa brizantha cv. Marandu and corn silage + Urochloa brizantha cv. Marandu + pigeon pea). Average daily gain (kg/day) and the period during which the lambs were confined, was not influenced by the different diets. The use of silage from corn consortium with Marandu and pigeon pea in the diet of lambs led to an increase in dry matter intake (kg/day) and further compounded the times spent for ruminating, chewing and distribution of physically effective fiber. Diets showed favorable profitability in finishing lambs in confinement; however, the greatest economic return was obtained with the system in which the animals were fed with silage corn. The diet containing corn silage in consortium with Marandu and pigeon pea provided increased crude protein intake (kg/day) compared to corn silage (0,273 and 0,238, respectively). The potential production of greenhouse gases, was lower for diets containing corn silage in consortium, ...
Mestre
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Legleiter, Leon R. "Responses to rumen undegradable protein as a source of essential amino acids in feedlot cattle /." free to MU campus, to others for purchase, 2003. http://wwwlib.umi.com/cr/mo/fullcit?p1418043.
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Skloss, Stewart James. "Evaluation of the TEOM method for the measurement of particulate matter for Texas cattle feedlots." [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-2634.
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Stone, Anton. "The effect of respiratory disease on the performance of cattle in two South African feedlots." Diss., University of Pretoria, 2004. http://upetd.up.ac.za/thesis/available/etd-07262005-145352/.
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Andrighetto, Cristiana 1974. "Características qualitativas da carne de bubalinos murrah castrados e abatidos em diferentes períodos de confinamento /." Botucatu : [s.d.], 2007. http://hdl.handle.net/11449/104991.
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Orientador: André Mendes JorgeBanca: Roberto de Oliveira Roça
Banca: José Roberto Sartori
Banca: Evaldo Antonio Lencioni Titto
Banca: Rubén Roberto Velazco Gutierrez
Resumo: O ultra-som é utilizado também como uma ferramenta para estimar a área de olho de lombo e a espessura de gordura subcutânea em animais de produção. Os trabalhos sobre o uso do ultra-som são direcionados aos bovinos, portanto é imprescindível estudar esta ferramenta na criação dos bubalinos. Foram utilizados 20 bubalinos, da raça Murrah, castrados, descornados, com idade média inicial de 15 meses. Submeteram-se os animais a quatro tratamentos, abatidos aos 75, 100, 125, 150 dias de confinamento. As medidas realizadas foram área de olho de lombo, espessura de gordura subcutânea do dorso (avaliadas entre a 12ª e 13ª costelas) e a espessura de gordura da garupa, mensuradas pelo ultra-som quando os búfalos atingiram o ponto de abate pelo período de confinamento e, na carcaça após o abate, através da. A área de olho de lombo, espessura de gordura do dorso e da garupa, realizadas pelo ultra-som e na carcaça, apresentaram efeito linear crescente (P<0,05). O ultra-som subestimou a área de olho de lombo da carcaça, sendo, a diferença entre as medidas -5,4cm2. A área de olho de lombo para 100kg de carcaça, no último abate foi 27,8cm2 e a espessura de gordura subcutânea do dorso 3,8mm. As correlações medidas pelo ultra-som e na carcaça foram 0,75 (P<0,05) para área de olho de lombo e 0,82 (P<0,05) para espessura de gordura subcutânea no dorso. As características de carcaça medidas por ultra-som, em bubalinos, apresentam boas correlações com as medidas realizadas na carcaça.
Abstract: The ultrasound is used too as estimate the ribeye and fat thickness. The works about the use of ultrasound are managed to cattle, therefore it is essential to study the use of this tool to raise buffaloes. Twenty castrated, hornless, Murrah buffaloes with average initial age of 15 months old. The buffaloes were separated in four groups that were slaughtered in 75, 100, 125, 150 days of feedlot. The measures were ribeye, back fat thickness (between 12ª and 13ª ribs) and fat thickness in rump, measured by the ultrasound when the buffaloes reached the slaughter point by the feedlot stages and in the carcass at the moment of slaughter. The ribeye, back fat thickness and fat thickness in rump presented linear increase effect (P<.05). The average difference between the ribeye in ultrasound and carcass was 5.4 cm2, we observe that the ultrasound underestimated the ribeye in carcass. The ribeye for 100kg of carcass, the last slaughter was 27.8 cmø and back fat thickness 3.8mm. The increase of fat thickness measure for days in feedlot in carcass and ultrasound was similar between back and rump. The correlations measured by the ultrasound and carcass were 0.75 (P<.05) for ribeye and 0.82 (P<.05) for back fat thickness. The characteristics of the measures in ultrasound showed good correlations with measures at the moment of slaughter of the ribeye and back fat thickness in differents stages of feedlot.
Doutor
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Stevenson, Sam M. L., and University of Lethbridge Faculty of Arts and Science. "Transfer of rifampicin-resistant Escherichia coli among feedlot cattle." Thesis, Lethbridge : University of Lethbridge, Facutly of Arts and Science, 2002, 2002. http://hdl.handle.net/10133/237.
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Transfer and shedding of a rifampicin-resistant strain of Escherichia coli (RREC) among cattle was studied in a research feedlot comprised of 30 pens of 11 or 12 yearling steers. On 3 separate occasions, 9,6 and 6 of the 12 steers in 3 different peripheral pens in the lot were orally inoculated with 1011 cells of an unmodified RREC isolate from bovine feces. Fecal swabs were preformed on all 360 steers in the feedlot immediately prior to and at approximately 5-week intervals thereafter. Following inoculation, fecal grab samples were collected daily from all 12 pen mates for up to 4 months. In all 3 trials, the inoculated steers each shed RREC within 24 h of inoculation. All 12 steers in each inoculated pen were positive for RREC within 48 h; all 36 steers shed RREC intermittently throughout the three sampling periods. Transfer to 4 steers in an adjacent pen was confirmed only during the first trial (3 steers shed once each on day 8, day 26 or day 40; the fourth shed on 6 occasions between days 8 and 40). Transfer to non-adjacent pens was not detected during any of the 3 trials. All recovered RREC isolates were compared to the inocula using LMX agar and fatty acid methyl ester (FAME) analysis. Additionally, select recovered isolates were subjected to carbon source utilization tests. The three inocula were further subjected to 16S rRNA sequence analysis, minimum inhibitory antibiotic concentration profiles and pulsed-field gel electrophoresis and were determined to be the same strain. It was observed with the exception of the pen floor, that the resistant strain did not move through the animal feedlot environment, as easily or pervasively as other studies suggested. The RREC did not persist in the feedlot environment beyond the 4-month trial period. Fecal contamination form the pen floor, animal-to-animal contact and the chute system may have facilitated transfer of the resistant strain between animals. Animal stress may have facilitated the pen-to-pen transfer observed during trial 1, as the inoculation was conducted within 1 week of the steers' arrival in the feedlot.xii, 102 leaves : ill. ; 28 cm.
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Andrighetto, Cristiana [UNESP]. "Características qualitativas da carne de bubalinos murrah castrados e abatidos em diferentes períodos de confinamento." Universidade Estadual Paulista (UNESP), 2007. http://hdl.handle.net/11449/104991.
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andrighetto_c_dr_botfmvz.pdf: 293280 bytes, checksum: dda49cdd60873926170b0a3b5a781ff1 (MD5)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Universidade Estadual Paulista (UNESP)
O ultra-som é utilizado também como uma ferramenta para estimar a área de olho de lombo e a espessura de gordura subcutânea em animais de produção. Os trabalhos sobre o uso do ultra-som são direcionados aos bovinos, portanto é imprescindível estudar esta ferramenta na criação dos bubalinos. Foram utilizados 20 bubalinos, da raça Murrah, castrados, descornados, com idade média inicial de 15 meses. Submeteram-se os animais a quatro tratamentos, abatidos aos 75, 100, 125, 150 dias de confinamento. As medidas realizadas foram área de olho de lombo, espessura de gordura subcutânea do dorso (avaliadas entre a 12ª e 13ª costelas) e a espessura de gordura da garupa, mensuradas pelo ultra-som quando os búfalos atingiram o ponto de abate pelo período de confinamento e, na carcaça após o abate, através da. A área de olho de lombo, espessura de gordura do dorso e da garupa, realizadas pelo ultra-som e na carcaça, apresentaram efeito linear crescente (P<0,05). O ultra-som subestimou a área de olho de lombo da carcaça, sendo, a diferença entre as medidas -5,4cm2. A área de olho de lombo para 100kg de carcaça, no último abate foi 27,8cm2 e a espessura de gordura subcutânea do dorso 3,8mm. As correlações medidas pelo ultra-som e na carcaça foram 0,75 (P<0,05) para área de olho de lombo e 0,82 (P<0,05) para espessura de gordura subcutânea no dorso. As características de carcaça medidas por ultra-som, em bubalinos, apresentam boas correlações com as medidas realizadas na carcaça.
The ultrasound is used too as estimate the ribeye and fat thickness. The works about the use of ultrasound are managed to cattle, therefore it is essential to study the use of this tool to raise buffaloes. Twenty castrated, hornless, Murrah buffaloes with average initial age of 15 months old. The buffaloes were separated in four groups that were slaughtered in 75, 100, 125, 150 days of feedlot. The measures were ribeye, back fat thickness (between 12ª and 13ª ribs) and fat thickness in rump, measured by the ultrasound when the buffaloes reached the slaughter point by the feedlot stages and in the carcass at the moment of slaughter. The ribeye, back fat thickness and fat thickness in rump presented linear increase effect (P<.05). The average difference between the ribeye in ultrasound and carcass was 5.4 cm2, we observe that the ultrasound underestimated the ribeye in carcass. The ribeye for 100kg of carcass, the last slaughter was 27.8 cmø and back fat thickness 3.8mm. The increase of fat thickness measure for days in feedlot in carcass and ultrasound was similar between back and rump. The correlations measured by the ultrasound and carcass were 0.75 (P<.05) for ribeye and 0.82 (P<.05) for back fat thickness. The characteristics of the measures in ultrasound showed good correlations with measures at the moment of slaughter of the ribeye and back fat thickness in differents stages of feedlot.
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Carrington, Christopher Antony Paul. "The role of Mycoplasma species in bovine respiratory disease complex in feedlot cattle in South Africa." Electronic thesis, 2007. http://upetd.up.ac.za/thesis/available/etd-10312007-150332/.
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Bond, Bradley J. "Evaluating the cost and performance of vegetative treatment systems on open beef feedlots in the Midwestern United States." [Ames, Iowa : Iowa State University], 2010. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1476278.
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Whittington-Jones, Craig Alun. "The ecology of the red-billed quelea Quelea Quelea (Linnaeus) and other granivorous birds at Eastern Cape feedlots." Thesis, Rhodes University, 2002. http://hdl.handle.net/10962/d1003286.
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Red-billed Quelea Quelea quelea have expanded their range in the Eastern Cape and now occur throughout the year in new areas. Recent changes in agricultural practice have probably been a contributing factor as flocks are larger than previously recorded and were more often associated with artificial food sources than natural grasses. Ringing and census data indicate that quelea have reduced movements during the non-breeding season and may display strong fidelity (over successive years) to dry season quarters with reliable food supplies. Although the recapture/recovery rate for quelea in the Eastern Cape (1.0-2.5%) was higher than the national average, it was still lower than expected and there may be considerable movement between nearby feeding sites. Some quelea breed locally, but most disperse during summer and their numbers at the feedlots were generally highest in winter and spring. The breeding season of quelea is later than other ploceids in the region and post-nuptial moult overlaps with winter. Replacement of primary wing feathers is relatively slow (124 days), and this is considered an adaptation to minimise disruption of flight capabilities and insulation. Significantly more quelea in the Eastern Cape have breeding plumage suffused with pink than in other southern African populations. However, during the non-breeding season there is apparently considerable intermixing between local populations and those from further north and the existence of a local sub-species is not supported. Seeds of two grass species, Echinochloa sp. and Urochloa panicoides, and two weed species, Amaranthus sp. and Chenopodium sp., were important in the diet of both quelea and Laughing Doves Streptopelia senegalensis. Maize comprised a large proportion of the diet of these species and losses at one ostrich feedlot were estimated at over R 17 000 in two years. Dependence on artificial food sources was generally greatest in winter and spring, but economically significant damage was not confined to this period. Alpha-chloralose showed good potential for reducing numbers of problem birds at livestock feedlots. However, the dynamic nature of problem bird populations favours a non-lethal management approach. Reduction of feed loss through manipulation of the ostrich ration could provide a relatively cheap and effective alternative to lethal control if applied appropriately.
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Van, Wyk Susan. "The effects of growth stimulants used at cattle feedlots, on reproductive health and thyroid function of Sprague-Dawley rats." Diss., University of Pretoria, 2011. http://hdl.handle.net/2263/24885.
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Reports of endocrine disrupting potential of common environmental chemicals and the effects on reproductive health are well documented in literature. It has been suggested that deteriorating male reproductive health could be due to in utero exposures to these chemicals. The effects mediated through endocrine disrupting chemicals (EDCs) are on the fetus and may therefore be trans-generational. Ultimately, these chemicals land up in aquatic systems and affect wildlife and humans. Humans are exposed to these chemicals through multiple routes including atmosphere, water, occupational, domestic and food consumption. South Africa (SA) is an important livestock producer with about 13.8 million cattle within the feedlot industry contributing up to 80% of the total beef production. Veterinary growth stimulants (VGS) are used by beef producers to enhance growth in cattle. In SA, the following five VGS have been approved for use in beef products under the Register Act 36 of 1947, estradiol, progesterone and testosterone (natural), α'-zearalanol and trenbolone (synthetic). These VGS and their metabolites are environmentally stable compounds. The excretions from the animals are not treated and land up in the local aquatic systems, indirectly posing a health risk. In SA no research has been done on VGS associated with feedlot activities. The aim of this study was to investigate the effects of a mixture of VGS, as possible EDCs on the reproductive health and thyroid function in male rats in utero, during lactation and life-time exposure. The (anti)estrogenic and (anti)androgenic activity in water from specific feedlots was determined by using a battery of screening bio-assays. Water samples were collected over a period of a year and assessed for EDC activity in the recombinant yeast screen (YES), the T47D-KBluc (estrogenic) and the MDA-Kb2 (androgenic) bioassays. The OECD (Organization for Economic Co-operation and Development) 415 protocol, (1983) for a one-generation reproduction toxicity study, was modified to accommodate one control and three experimental groups. The experimental groups were orally gavaged with mixtures of: zilpaterol, diethylstilbestrol (DES) and α-zearalanol (Group 2; estogenic); with β'-trenbolone and methyltestosterone (MT) (Group 3; androgenic); a combination of compounds (Group 4; estrogenic and androgenic) and the Control group received cottonseed oil only. The bio-assay results indicated that water samples analysed from selected feedlots contained compounds with estrogenic activity. The shorter anogenital distance (AGD) (Group 3), decreased seminal vesicle mass (Group 4), decreased prostate mass (Group 4), increased lumen diameter (Group 3 and 4), lowered sperm concentration (Group 3), and increased T4 (Group 2 and 3) differed significantly from the control. The body weight of the males in Group 2 in the F2 generation was significantly lower than the control. The F2 females in Group 2, 3 and 4 were also significantly lower than the control. The reduced AGD, decreased seminal vesicle and increased T4 (thyroxine) might be the result of an estrogenic effect. The reduced sperm concentration might be the result of in utero and lactation exposure to these VGS. The bio-assays confirmed estrogenic activity in the feedlot water sources. The reproductive toxicology study findings confirm the hypothesis that VGS can act as EDCs and could therefore be responsible for negative reproductive effects and thyroid function. More research is needed to investigate the effects of VGS mixtures at different concentrations on male reproductive health, thyroid function and their offspring. AFRIKAANS : Goed gedokumenteerde literatuur dui aan dat chemikalieë wat algemeen in die omgewing gevind word, die potensiaal het om die manlike voortplantingstelsel aan te tas. Dit word gespekuleer dat in utero blootstelling verantwoordelik kan wees vir hierdie agteruitgang. Die fetus en daarop- volgende geslagte se gesondheid kan ook beÏnvloed word deur chemikalieë. Hierdie chemikalieë het die potensiaal om die watersisteme te bereik en gevolglik dier en menslike gesondheid te beÏnvloed. Blootstelling kan plaasvind deur verskeie roetes wat die atmosfeer, water, werksomstandighede, huishoudelike produkte en gekontamineerde voedsel insluit. Suid-Afrika (SA) is 'n belangrike produsent van vleisprodukte met omtrent 13.8 miljoen beeste wat bydra tot 80% van die vleisproduksie. Veterinêre-groei-stimulante (VGS) word gebruik om die vleisproduksie te verbeter. Vyf groei stimulante naamlik estradiol, progesteroon, testosteroon (natuurlike), α-zearalanol en trenboloon (sinteties) is goedgekeur onder die Wet 36 van 1947, vir groei produksie van beeste. Hierdie VGS en hul metaboliete is stabiel in die natuur. Die fekale en urinere uitskeidingsprodukte van die diere word nie behandel nie en eindig op in ons waterstelsels. Geen navorsing is nog in SA gedoen om die potensiële bydraes wat voerkrale tot die besoedeling van water lewer, te bestudeer nie. Die doel van die studie was om die gesamentlike effekte van mengsels VGS as moontlike endokrien-ontwrigtende chemicalieë (EOC) op die manlike voortplantingstelsel en tiroïdhormone van mannetjiesrotte na in utero-, gedurende laktasie- en na 'n leeftyd-blootstelling te bepaal. Die (anti)estrogeniese en (anti)androgeniese aktiwiteit in water vanaf spesifieke voerkrale is met behulp van 'n reeks biologiese seltoetse bepaal. Watermonsters is geanaliseer met die gisseltoets (YES)(estrogenies), die T47D-KBluc (estrogenies) en die MDA-Kb2 (androgenies). Die OECD 415 protokol (1983) vir een generasie reproduktiewe toksologie toets was aangepas om een kontrole en drie eksperimentele groepe te huisves. Die eksperimentele groepe rotte is oraal gedoseer met 'n mengsel van zilpaterol, dietielstilbestrol (DES) en α-zearalanol (Groep 2); β-trenboloon en metieltestosteroon (Groep 3); 'n kombinasie van al bogenoemde (Groep 4); en 'n kontrole groep wat katoensaad olie VGS ontvang het nie. Estrogeniese aktiwiteit en sitotoksisiteit was teenwoordig in die water vanaf die voerkrale. Die verkorte anogenitale afstand (AGD) (Groep 3), kleiner seminale vesikel (SV) massa (Groep 4), kleiner prostaat massa (Groep 4), groter lumen deursneë (Groep 3 en 4), laer spermtelling (Groep 3), verhoogde T4 (Groep 2 en 3), het almal statisties-betekenisvol van die kontrole groep verskil. In die F2 generasie het die liggaamsmassas van die mannetjies in Groep 2 en liggaamsmassas van die wyfies in Groepe 2, 3 , 4, almal statisties-betekenisvol laer as die kontrole Groep. Die verkorte AGD, kleiner SV en verhoogde T4 kan moonlik wees as gevolg van 'n estrogeniese effek en die verlaagde sperm konsentrasie weens 'n in utero en laktasie blootstelling. Die biologiese seltoetse het die teenwoordigheid van estrogeniese aktiwiteit in voerkrale se water bevestig. Die gevolge van die blootstelling van EOC mengsels op voortplantings-parameters bevestig die moontlikheid van EOC effek geassosieer met VGS. Verdere navorsing is nodig om die dosisresponsverhoudings van verskillende VGS te ondersoek. CopyrightDissertation (MSc)--University of Pretoria, 2011.
School of Health Systems and Public Health (SHSPH)
Unrestricted
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Van, Winkle Tyler W. "An evaluation of distller's grain price relationships and implications of increased ethanol production on grain processing practices in commercial feedlots." Thesis, Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/921.
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Lange, Jennifer Marie. "Engineering analysis of the air pollution regulatory process impacts on the agricultural industry." Thesis, Texas A&M University, 2008. http://hdl.handle.net/1969.1/85899.
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The EPA press release dated February 23, 2004 states that the three Buckeye Egg Farm facilities had the potential to emit more than a combined total of 1850 tons per year of particulate matter (PM). This number was based on flowrate calculations that were three times higher than those measured as well as a failure to include particle size distributions in the emissions calculations. The annual PM emission for each facility was approximately 35 tons per year. The EPA was unjustified in requiring Buckeye Egg Farm to obtain Title V and PSD permits as the facilities could not have met the thresholds for these permits. Engineers need to be concerned with correctly measuring and calculating emission rates in order to enforce the current regulations. Consistency among regulators and regulations includes using the correct emission factors for regulatory permitting purposes. EPA has adopted AERMOD as the preferred dispersion model for regulatory use on the premise that it more accurately models the dispersion of pollutants near the surface of the Earth than ISCST3; therefore, it is inappropriate to use the same emission factor in both ISCST3 and AERMOD in an effort to equitably regulate PM sources. For cattle feedlots in Texas, the ISCST3 emission factor is 7 kg/1000 hd-day (16 lb/1000 hd-day) while the AERMOD emission factor is 5 kg/1000 hd-day (11 lb/1000 he-day). The EPA is considering implementing a crustal exclusion for the PM emitted by agricultural sources. Over the next five years, it will be critical to determine a definition of crustal particulate matter that researchers and regulators can agree upon. It will also be necessary to develop a standard procedure to determine the crustal mass fraction of particulate matter downwind from a source to use in the regulatory process. It is important to develop a procedure to determine the particulate matter mass fraction of crustal downwind from a source before the crustal exclusion can be implemented to ensure that the exclusion is being used correctly and consistently among all regulators. According to my findings, the mass fraction of crustal from cattle feedlot PM emissions in the Texas High Plains region is 52%.
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Moretti, Matheus Henrique [UNESP]. "Estratégias alimentares para a recria e terminação de tourinhos Nelore." Universidade Estadual Paulista (UNESP), 2015. http://hdl.handle.net/11449/124016.
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000833017.pdf: 1030044 bytes, checksum: 64ce5ae59ac1ab2cf3290652a62b8191 (MD5)Foram realizados dois experimentos para avaliar o efeito de planos nutricionais sobre o ganho de peso e carcaça, assim como as mudanças na composição corporal de tourinhos Nelore. O experimento 1 foi realizado de julho de 2009 a setembro de 2010, e foi dividido em três fases. As fases I e II foram referentes ao período de recria e a fase III a terminação dos animais. Na fase I os animais receberam 2 suplementos: 1) suplemento proteico (SPI) ou 2) suplemento proteico energético (SPEI). Na fase II os tratamentos foram distribuídos em esquema fatorial 2 x 4, sendo o efeito de dois históricos nutricionais da fase I associados a quatro tratamentos na fase II: 1) sal mineral (SM) 2) suplemento proteico (SPII), 3) suplemento proteico energético (SPEII); 4) suplemento energético (EN). A fase III correspondeu a terminação, sendo os tratamentos distribuídos em esquema fatorial 2 x 4 x 2, com dois históricos alimentares da fase I, quatro da fase II divididos em duas estratégias de terminação: 1) pasto com alto concentrado (PA) ou 2) confinamento (CO). Utilizou-se 129 tourinhos Nelore, com 8 ± 2 meses de idade e peso corporal de 204,6 ± 5,2 kg. O experimento 2 foi realizado de julho de 2011 a setembro de 2012, e foi dividido em três fases da mesma forma que no experimento 1. Na fase I os tratamentos foram: 1) suplemento proteico (SP) ou 2) suplemento proteico energético (SPEI). Na fase II os tratamentos foram distribuídos em esquema fatorial 2 x 2, sendo o efeito de dois históricos nutricionais da fase I associados a dois tratamentos na fase II: 1) sal mineral (SM) 2) suplemento proteico energético (SPEII). Na fase III os tratamentos também foram distribuídos em esquema fatorial 2 x 2 x 2, com dois históricos alimentares da fase I, dois da fase II divididos em dois níveis de fornecimento de ração: 1) 15 g.kg-1 PC ou 2) 20 g.kg-1 PC. Utilizou-se 78 tourinhos Nelore, com 8 ± 2 meses de idade e peso corporal de ...
Two trials were made aiming to evaluate the effect of different nutritional plans on body and carcass gain, as well as changes in body composition of Nelore cattle. The trial 1 started in July, 2009 and finished in September, 2010, and was divided in three phases. The phases I and II corresponded to the growing phase, and the phase III corresponded to the finishing phase. In phase I the animals were randomly assigned to 1 of 2 treatments consisting of: a) protein (PRI) or, b) protein and energy (PEI) supplement. The phase II for each of the phase I treatments, the animals were randomly assigned in factorial (2 x 4) to 1 of 4 treatments including: a) mineral salt (MN), b) protein (PRII), c) protein and energy (PEII) and d) energy (EN) supplement. The phase III for each of the phase I and II treatments, the animals were randomly assigned in factorial (2 x 4 x 2) to 1 of 2 treatments: finishing in 1) pasture (PA) or 2) feedlot (FE), in both treatments the animals were fed high concentrate. 129 young Nelore bulls, were 8 ± 2 months of age and BW of 204.6 ± 5.2 kg were utilized. The trial 2 started in July, 2011 and finished in September, 2012, and was divided in three phases as the trial 1. In phase I the animals were randomly assigned to 1 of 2 treatments consisting of: a) protein (PRI) or, b) protein and energy (PEI) supplement. The phase II for each of the phase I treatments, the animals were randomly assigned in factorial (2 x 2) to 1 of 2 treatments including: a) mineral salt (MN), b) protein and energy supplement (PEII). The phase III for each of the phase I and II treatments, the animals were randomly assigned in factorial (2 x 2 x 2) to 1 of 2 treatments: 1) medium or 2) high feed. 78 young Nelore bulls, were 8 ± 2 months of age and BW of 171.7 ± 6.4 kg were utilized. Measurements of ADG, gain and composition of carcass were made. All the data were analysed as a randomized factorial design using the PROC MIXED of the SAS ...
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Lowe, Ross M. S., and University of Lethbridge Faculty of Arts and Science. "Escherichia coli O157:H7 lineage persistence and colonization of cattle in vitro." Thesis, Lethbridge, Alta. : University of Lethbridge, Dept. of Biological Sciences, c2009, 2009. http://hdl.handle.net/10133/2509.
Full textAbstract:
Escherichia coli O157:H7 is an important human pathogen that resides primarily in cattle and feedlot environments. E. coli O157:H7 can be divided into phylogenetic groups termed lineages; lineage I strains are responsible for most human illnesses. An understanding of the etiology of these lineages within cattle and the feedlot environment could allow for more effective surveillance and mitigation strategies. There were no lineage associated differences in growth or survival of E. coli O157:H7 in bovine feces at 4°C, 12°C or 25°C. Lineage I strains more readily colonized cattle jejunum tissue and a bovine colonic cell line than lineage II and intermediate type strains. Enhanced colonization of cattle by lineage I strains may increase the persistence of these strains in feedlots via re-infection and increased shedding. This outcome could increase the transmission of lineage I strains to the food supply and increase the potential for these strains to cause human illness.xiii, 101 leaves ; 29 cm
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Erasmus, Morné. "Amino acid requirements of feedlot cattle according to the duodenal and whole empty body essential amino acid profile." Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52085.
Full textAbstract:
Thesis (MScAgric)--University of Stellenbosch, 2001.ENGLISH ABSTRACT: The purpose of this study was to determine the essential amino acid requirements of beef cattle under feedlot conditions through evaluation of the duodenal and whole empty body essential amino acid compositions. To define the ideal protein required for growth, the whole empty body essential amino acid compositions of 8 beef steers (Simmental and Hereford crosses) was investigated. The amino acid composition of the components (carcass, metabolic organs and residual fraction), was pooled relative to their respective mass and protein contribution, resulting in the calculated whole empty body amino acid composition: arginine 6.81; histidine 2.69; isoleucine 4.02; leucine 6.96; lysine 7.43; methionine 2.01; phenylalanine 4.03; threonine 4.01; valine 5.30; tryptophan 0.82. Variations in profiles were found between scientific reports, either indicating that ratios change with growth and implants or possibly through genotype. The present study's body amino acid ratios were used to estimate dietary amino acid requirements through evaluation of the duodenal essential amino acid compositions from three different maize based feedlot diets. Although there was a general increase in the biological value of protein after rumen fermentation, the duodenal essential amino acids in comparison with the whole empty body recorded deficient/unbalanced profiles of essential amino acids for growth. The chemical scores suggested that the first-to-thirdlimiting amino acids in the duodenal digesta of beef cattle, that received three different commercially available feedlot diets, were: histidine, lysine, methionine/arginine (Diet 1), histidine, arginine, lysine (Diet 2) and arginine, methionine, histidine (Diet 3). Thedisproportionate duodenal amino acid concentrations obtained from the three diets, emphasise the necessity to enhance the intestinal delivery of amino acid profiles through different undegradable protein sources, with the objective to maximise protein utilisation and obtain the genetic potential for optimal growth in feedlot cattle. When amino acid requirements and flows to the duodenum were simulated using the Cornell Net Carbohydrate and Protein system (CNCPS), predictions indicated that lysine amino acid flow was limiting the metabolizable allowable average daily gain in Diet 1 and 3. Predicted profiles indicated that the order of limitation was: lysine, arginine, histidine (Diet 1), lysine, arginine, histidine, methionine (Diet 2) and lysine, arginine, histidine (Diet 3). The predicted profiles were in accordance with observed duodenal values, except for methionine that was observed limiting in Diet 1 and 3; however, the sequence and extent of limitation varied. Results indicate that prediction models have potential in predicting requirements; however there are still limitations for use to accurately define requirements for particular EAA's. From the present study, it is clear that the protein accretion was constrained by quantity and/or disproportionality of amino acids available for absorption. Further research should therefore be directed towards obtaining a more desirable array of amino acids to the lower digestive tract that is digestible, absorbable and an economically viable option for the feedlot operator.
AFRIKAANSE OPSOMMING: Aminosuurbehoeftes van Voerkraalbeeste Volgens die Duodenale en Totale Lee Liggaam Essensiele Aminosuur Profiel: Die doel van hierdie studie was om die essensiele aminosuur vereistes van vleisbeeste onder voerkraal toestande te bepaal deur die evaluering van die duodenale en totale lee liggaam essensiele aminosuursamesteilings. Om die idea Ie proteiene wat vir groei benodig word te definieer, is 'n ondersoek ingestel na die totale lee liggaam essensiele aminosuursamesteilings van 8 vleisbees osse (Simmetailer en Hereford kruise). Die aminosuursamesteiling van die komponente (karkas, metaboliese organe en residuele fraksie), se massa en proteien bydrae is gebruik om die totale lee liggaam aminosuursamestelling 5005 volg te bereken: arginien 6.81; histidien 2.69; isoleusien 4.02; leusien 6.96; lisien 7.43; metionien 2.01; fenielalanien 4.03; treonien 4.01; valien 5.3; triptofaan 0.82. Variasies in profiele tussen wetenskaplike verslae is gevind. Dit dui daarop dat groei en inplantings of moontlik genotipe 'n invloed op profiele kan he. Die huidige studie se liggaam aminosuurverhoudings is gebruik om die dieet aminosuurbehoeftes te skat deur evaluering van die duodenale essensiele aminosuursamesteilings van drie verskiilende mielie-gebaseerde voerkraal diete. Alhoewel daar 'n algemene toe name in die biologiese waarde van die proteien na rumen fermentasie was, het die duodenale essensiele aminosure in vergelyking met die totale lee liggaam, ongebalanseerde profiele van essensiele aminosure vir groei getoon. Die chemiese teilings toon aan dat die eerste-tot-derde-beperkende aminosure in die duodenale inhoud van vleisbeeste wat drie verskillende kommersieel beskikbare voerkraal diete ontvang het, soos volg is: histidien, lisien, metionieniarginien (Dieet 1), histidien, arginien, lisien (Dieet 2) en arginien, metionien, histidien (Dieet 3). Die ongebalanseerde aminosuur konsentrasies wat in die duodenum van die drie dlete verkry is, beklemtoon die noodsaaklikheid om die intestinale lewering van aminosuurprofiele te verbeter deur verskillende nie-degradeerbare proteien bronne te voer. Die doelwit moet wees om proteien verbruik te optimaliseer en daardeur die genetiese potensiaal vir optimale groei in voerkraalbeeste te bereik. Met die simulering van aminosuurbehoeftes en vloei na die duodenum van die drie standaard voerkraal diete met behulp van die "Cornell Net Carbohydrate and Protein System" (CNCPS), het voorspellings gewys dat lisien aminosuurvloei die metaboliseerbare toelaatbare gemiddelde daaglikse toename in Dieet 1 en 3 beperk het. Voorspelde profiele wys dat die volgorde van beperking soos volg sou wees: lisien, arginien, histidien (Dieet 1), lisien, arginien, histidien, metionien (Dieet 2)' en lisien arginien, histidien (Dieet 3). Die voorspelde profiele was in ooreenstemming met die waargeneemde duodenale waardes, behalwe vir metionien wat beperkend was in Dieet 1 en 3; die volgorde en mate van beperking was egter verskillend. Resultate wys dat voorspellingsmodelle die potensiaal het om behoeftes te voorspel. Vir die akkurate definisie van behoeftes vir spesifieke essensiele aminosuure is daar egter nog beperkinge. Uit die huidige studie, is dit duidelik dat protetenneerleqqinq deur die hoeveelheid en/of oneweredigheid van geabsorbeerde aminosure beperk is. Verdere navorsing moet dus fokus op die verkryging van In meer geskikte profiel van aminosure wat verteerbaar, opneembaar en 'n ekonomiese lewensvatbare opsie vir die voerkraalbestuurder is.
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Monção, Flávio Pinto. "Suplementação e uso da virginiamicina como moduladores do desempenho de bovinos Nelore na recria e seus efeitos na terminação em confinamento /." Jaboticabal, 2017. http://hdl.handle.net/11449/150934.
Full textAbstract:
Orientador: Gustavo Rezende SiqueiraBanca: Danilo Domingues Millen
Banca: Josiane Fonseca Lage
Banca: Ivanna Moraes de Oliveira
Banca: Márcia Helena Machado da Rocha Fernandes
Resumo: Cento e sessenta e oito tourinhos Nelore com peso inicial de 228 ± 19 kg e idade de 10 meses e 12 tourinhos Nelore canulados no rúmen foram utilizados com objetivo de avaliar diferentes estratégias nutricionais associada com virginiamicina (VM) na fase de recria em pastagem de Brachiaria brizantha cv. Marandu sobre o ganho em peso corporal (PC), parâmetros ruminais, sanguíneos, urinários e consumo de nutrientes. Ademais, objetivou-se também avaliar se os benefícios proporcionados pelas estratégias nutricionais associada com VM na fase de recria são mantidos na fase de terminação em confinamento com diferentes dias de cocho (88 dias e 121 dias). A fase de recria foi dividida em estação seca (26/08/14 a 10/12/14, 105 dias) e estação verão (10/12/14 a 25/03/15, 105 dias) e outono (25/03/15 a 20/06/15, 87 dias), totalizando 297 dias experimentais. Na recria, os animais receberam 1 de 4 estratégias nutricionais: suplemento mineral com ureia (SU, ad libitum) durante estação seca e suplemento mineral (SM, ad libitum) no verão e outono; ou suplemento proteico energético na estação seca (SPE, 3 g/kg PC por dia), suplemento proteico no verão (SP, 1 g/kg PC por dia) e SPE no outono (3 g/kg PC por dia). Dentro de cada estratégia nutricional, foi avaliada a inclusão ou não de aditivo alimentar VM, na dose de 40 mg para cada 100 kg de PC. A área experimental, dividida em 12 piquetes (3,5 a 4 ha cada) e a área e o peso dos animais foram os fatores de blocagem. Foram utilizados 45 animais po... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: One hundred and sixty eight young bulls with initial weight of 228 ± 19 kg and age of ten months and twelve Nellore bulls cannulated in the rumen were used to evaluate different nutritional strategies associated with virginiamycin (VM) during the growing phase in pastures of Brachiaria brizantha cv. Marandu on body weight gain (BW), ruminal, blood and urinary parameters and nutrient intake. In addition, evaluate if the benefits provided by the nutritional strategies associated with VM in the growing phase are maintained termination phase in the feedlot in two-time (88 days and 121 days). The growing phase was divided in dry season (08/26/14 to 10/12/14, 105 days) and summer season (10/12/14 to 25/03/15, 105 days) and autumn (25/03/15 to 20/06/15, 87 days), totaling 297 experimental days. The animals received 1 of 4 nutritional strategies: mineral supplement with urea (SU, ad libitum) during dry season and mineral supplement (SM, ad libitum) in summer and autumn; or protein energy supplement in the dry season (SPE, 3 g/kg BW per day), protein supplement in the summer (SP, 1 g / kg BW per day) and SPE in the autumn (3 g / kg BW per day). Within each nutritional strategy, the inclusion or not of VM food additive was evaluated at a dose of 40 mg per 100 kg BW. A randomized complete block design was used in a 2 x 2 factorial scheme, with two strategies of supplementation and presence and absence of VM. The experimental area, divided into 12 paddocks (3.5 to 4.0 ha each), and BW wa... (Complete abstract click electronic access below)
Doutor
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Moretti, Matheus Henrique. "Estratégias alimentares para a recria e terminação de tourinhos Nelore /." Jaboticabal, 2015. http://hdl.handle.net/11449/124016.
Full textAbstract:
Orientador: Flávio Dutra de ResendeBanca: Ricardo Andrade Reis
Banca: Sérgio Raposo de Medeiros
Banca: Daniel Rume Casagrande
Banca: Joanis Tilermanos Zervoudaskis
Resumo: Foram realizados dois experimentos para avaliar o efeito de planos nutricionais sobre o ganho de peso e carcaça, assim como as mudanças na composição corporal de tourinhos Nelore. O experimento 1 foi realizado de julho de 2009 a setembro de 2010, e foi dividido em três fases. As fases I e II foram referentes ao período de recria e a fase III a terminação dos animais. Na fase I os animais receberam 2 suplementos: 1) suplemento proteico (SPI) ou 2) suplemento proteico energético (SPEI). Na fase II os tratamentos foram distribuídos em esquema fatorial 2 x 4, sendo o efeito de dois históricos nutricionais da fase I associados a quatro tratamentos na fase II: 1) sal mineral (SM) 2) suplemento proteico (SPII), 3) suplemento proteico energético (SPEII); 4) suplemento energético (EN). A fase III correspondeu a terminação, sendo os tratamentos distribuídos em esquema fatorial 2 x 4 x 2, com dois históricos alimentares da fase I, quatro da fase II divididos em duas estratégias de terminação: 1) pasto com alto concentrado (PA) ou 2) confinamento (CO). Utilizou-se 129 tourinhos Nelore, com 8 ± 2 meses de idade e peso corporal de 204,6 ± 5,2 kg. O experimento 2 foi realizado de julho de 2011 a setembro de 2012, e foi dividido em três fases da mesma forma que no experimento 1. Na fase I os tratamentos foram: 1) suplemento proteico (SP) ou 2) suplemento proteico energético (SPEI). Na fase II os tratamentos foram distribuídos em esquema fatorial 2 x 2, sendo o efeito de dois históricos nutricionais da fase I associados a dois tratamentos na fase II: 1) sal mineral (SM) 2) suplemento proteico energético (SPEII). Na fase III os tratamentos também foram distribuídos em esquema fatorial 2 x 2 x 2, com dois históricos alimentares da fase I, dois da fase II divididos em dois níveis de fornecimento de ração: 1) 15 g.kg-1 PC ou 2) 20 g.kg-1 PC. Utilizou-se 78 tourinhos Nelore, com 8 ± 2 meses de idade e peso corporal de ...
Abstract: Two trials were made aiming to evaluate the effect of different nutritional plans on body and carcass gain, as well as changes in body composition of Nelore cattle. The trial 1 started in July, 2009 and finished in September, 2010, and was divided in three phases. The phases I and II corresponded to the growing phase, and the phase III corresponded to the finishing phase. In phase I the animals were randomly assigned to 1 of 2 treatments consisting of: a) protein (PRI) or, b) protein and energy (PEI) supplement. The phase II for each of the phase I treatments, the animals were randomly assigned in factorial (2 x 4) to 1 of 4 treatments including: a) mineral salt (MN), b) protein (PRII), c) protein and energy (PEII) and d) energy (EN) supplement. The phase III for each of the phase I and II treatments, the animals were randomly assigned in factorial (2 x 4 x 2) to 1 of 2 treatments: finishing in 1) pasture (PA) or 2) feedlot (FE), in both treatments the animals were fed high concentrate. 129 young Nelore bulls, were 8 ± 2 months of age and BW of 204.6 ± 5.2 kg were utilized. The trial 2 started in July, 2011 and finished in September, 2012, and was divided in three phases as the trial 1. In phase I the animals were randomly assigned to 1 of 2 treatments consisting of: a) protein (PRI) or, b) protein and energy (PEI) supplement. The phase II for each of the phase I treatments, the animals were randomly assigned in factorial (2 x 2) to 1 of 2 treatments including: a) mineral salt (MN), b) protein and energy supplement (PEII). The phase III for each of the phase I and II treatments, the animals were randomly assigned in factorial (2 x 2 x 2) to 1 of 2 treatments: 1) medium or 2) high feed. 78 young Nelore bulls, were 8 ± 2 months of age and BW of 171.7 ± 6.4 kg were utilized. Measurements of ADG, gain and composition of carcass were made. All the data were analysed as a randomized factorial design using the PROC MIXED of the SAS ...
Doutor
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Jurgens, Andre Hendrik. "Feedlot performance and essential amino acid growth requirements of Dorper lambs." Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/52846.
Full textAbstract:
Thesis (MScAgric)--University of Stellenbosch, 2002.ENGLISH ABSTRACT: The Dorper is numerically the second most abundent of all the sheep breeds in South Africa. It is the most numerous sheep breed in the dry arid areas of South Africa which make out a very big portion of the natural grazing in South Africa. In this study the feedlot performance was specifically investigated since so little research has been done in this regard. In the first study (Chapter 1), the production efficiency, body components and commercial yield of 13 Dorper and 12 Merino lambs were investigated. A pelleted diet was fed ad lib and the water intake per day was measured. Lambs were slaughtered at 30kg and at 40kg live weight and cut up according to the South African commercial cuts. The weights of the organs, head, feet, skin and carcass were also recorded. Results from the first study showed that Dorpers had a lower (P<0.05) water efficiency (285.97 mVkgO75/day) than the Merinos (240.07 mVkg075/day), but had a higher (P<0.05) nitrogen retention. The head, feet, skin, heart, lungs, kidneys and diaphragm of Merino lambs were heavier (P<0.05). Merinos had heavier (P<0.05) breast and shank and thick rib (only at 40kg live weight) cuts. But the Dorper had a significantly heavier hindquarter (buttock and loin) which is the high-priced cut of any carcass. It seems that the Dorper will do well under feedlot conditions, and would possibly make a better commercial meat producer than the Merino under all circumstances. In the second study (Chapter 2), the free-ranging Dorper on natural grazing were compared with 7 Dorper lambs in the feedlot study. The essential amino acids in the duodenal contents were compared. The free-ranging Dorpers were randomly slaughtered at 40 kg live weight and a duodenal sample was collected. The feedlot Dorpers were also slaughtered at 40 kg live weight and a duodenal sample was taken. The second study indicated no significant differences between the EAA composition of the duodenal samples, whether protein quantity was taken into account (gAA/100g crude protein (CP)) or not (expressed as % of lysine). The chemical scores indicated that the two most limiting amino acids in the duodenal digesta for whole empty body growth were: arginine and histidine. Excess levels of amino acids tend to be present in all three duodenal digesta samples (isoleucine, leucine, lusine, methionine, phenylalaline, threonine and valine). The whole empty body EAA composition (g AA/100 g crude protein) was as follows 7.10 arginine; 2.40 histidine; 3.31 isoleucine; 7.22 leucine; 6.61 lysine; 1.62 methionine; 3.91 phenylalanine; 3.77 threonine and 4.85 valine. The composition can serve as an example of the ideal EAA requirements for whole empty body growth between 30 and 40 kg live weight of Dorper ram lambs. The duodenal amino acid concentrations of the free-ranging Dorper compared well with those of the feedlot Dorpers which suggests that the microbial organisms have a big influence on the amino acid concentration which reaches the intestines.
AFRIKAANSE OPSOMMING: Die voerkraal prestasie en essentiele aminosuur behoeftes van groeiende Dorper lammers: The Dorper is getalgewys die tweede mees talryke skaapras in Suid-Afrika. Dit is die mees talryke skaapras wat in die drce woestynagtige gebiede van Suid-Afrika aangetref word. Die gebiede beslaan die grootste oppervlakte van Suid-Afrika se natuurlike weiveld. In die studie is voerkraal prestasie van die Dorper nagevors, spesifiek omdat daar so min navorsing op hierdie gebied gedoen is. In die eerste studie (Hoofstuk 1) is die produksie doeltreffendheid, liggaams komponente en kornrnersiele produksie van 13 Dorper- en 12 Merino lammers ondersoek. 'n Verpilde rantsoen is ad lib gevoer en die water inname per dag is ook gekontroleer. Die lammers is geslag op 30 en 40 kg lewende gewig en die karkasse is daarna opgesny volgens die Suid-Afrikaanse kornmersiele karkassnitte. Die resultate van die eerste studie het getoon dat Dorpers 'n laer water potentiaal (P<0.05) (285 97 mflkgO 75/dag) as die Merinos (240.07 mVkg075/dag) het. Dorper lammers het ook 'n hoer (P<0.05) stikstof retensie. Die kop, vel, pote, hart, longe, niere en diafragma van Merino lammers was swaarder (P<0.05). Merinos se brisket en dikrib snitte weeg ook swaarder (P<0.05). Die Dorper het 'n beduidende swaarder agterkwart (len de en boud) gehad, wat die duurste snit is van enige karkas. Die Dorper het baie goed gedoen in die voerkraal toestande en sal waarskynlik onder aile omstandighede 'n hcer vleisproduksie op die Merino lewer. In die tweede studie (Hoofstuk 2), is die vryweiende Dopers op natuurlike weiding vergelyk met die Dorpers in 'n voerkraal. Die twee groepe Dorpers se essensiele aminosuur samestelling in hul dunderms is bepaal en vergelyk om te bepaal of daar enige tekorte teenwoordig is. Die Dorpers in die veld en in die voerkraal is op 40 kg lewende gewig geslag en monsters van die dunderm inhoud is gekollekteer. Die monsters is ontleed om te bepaal of daar enige betekenisvolle verskille in die essensiele aminosure van die dunderm inhoud tussen die veld Dorpers en voerkraal Dorpers was. Die tweede studie het geen betekenisvolle verskille getoon tussen die dunderm monsters se essensiele aminosure, of die hoeveelheid proteien (gAA/100g) in aanmerking geneem is of nie (uitgedruk as % lisien). Die chemiese telling dui aan dat die twee mees beperkende aminosure in die dunderm inhoud vir lee liggaam groei arginien en histidien was. Oormaat vlakke van aminosure kom voor in al drie dunderm inhoud monsters (isoleusien, leusien, lisien, metionien, femielalanien, treonien en valien). Die totale lee liggaam essensiele aminosuursamestelling (g aminosuur/100g ruprotein) was soos volg: 7.10 arginien; 2.40 histidien; 3.31 isoleusien; 7.22 leusien; 6.61 lisien; 1.62 metionien; 3.91 fenielalanien; 3.77 treonien en 4.85 valien. Hierdie aminosuursamestelling kan as 'n aanduiding dien vir die ideale aminosuurbehoeftes van Dorper ram lammers vir totale lee liggaamsgroei vanaf 30 tot 40 kg lewende massa. Die dunderm aminosuur konsentrasie van die Dorper in die veld stem goed ooreen met die van die voerkraal Dorper. Dit toon waarskynlik dat die mikrobe organismes in die rumen In groot invloed het op die aminosuur samestelling wat die dunderm bereik.
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Ferrari, Adriana Cristina. "Qualidade da carne de bovinos recriados em pastagens associada a suplementação e terminação a pasto ou no confinamento /." Jaboticabal, 2016. http://hdl.handle.net/11449/138281.
Full textAbstract:
Orientador: Ricardo Andrade ReisCoorientador: Josiane Fonseca Lage
Banca: Gustavo Rezende Siqueira
Banca: Roberto de oliveira Roça
Resumo: O objetivo do trabalho foi verificar se o histórico de recria no período das águas influenciou a qualidade da carne de tourinhos Nelore terminados no período seco em pasto ou confinamento. Durante a fase de recria os animais foram mantidos, em pasto de capim Marandu manejados em diferentes alturas de pastejo (15; 25 e 35 cm) em lotação continua e taxa de lotação variável, combinado com estratégias de suplementação e terminados no período seco, em pastagens com a dieta suplementada ou confinamento. O trabalho foi constituido de dois experimentos, do ano de 2012/2013, capitulo 2 e ano de 2013/2014, capítulo 3. No primeiro experimento, capitulo 2, foram coletadas amostras de carne de animais provenientes de seis tratamentos: ABSA- recria em pasto de 15 cm de altura e suplemento de 0,6% PC; AMSM- recria em pasto 25 cm de altura e suplemento de 0,3% PC; AASM- recria em pasto de 35 cm de altura e suplemento mineral, cada tratamento com terminação em pasto ou confinamento com nove repetições (animais). Foram utilizadas amostras do M. longissimus thoracis et lumborum (LTL), retiradas da meia-carcaça esquerda, entre a 12ª e 13ª costelas, posteriormente embaladas em filme plástico e, após 24 horas de resfriamento as amostras foram congeladas a -20ºC. Procedeu-se as determinações da maciez (força de cisalhamento) e perdas por cocção, coloração da carne e da gordura subcutânea, pH, composição centesimal, teor de colágeno e porcentagem de gordura intramuscular avaliados em Espec¬trofotôme... (Resumo completo, clicar acesso eletrônico abaixo)
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Klima, Cassidy L., and University of Lethbridge Faculty of Arts and Science. "Characterization of the genetic diversity and antimicrobial resistance in Mannheimia haemolytica from feedlot cattle." Thesis, Lethbridge, Alta. : University of Lethbridge, Dept. of Biological Sciences, c2009, 2009. http://hdl.handle.net/10133/2517.
Full textAbstract:
Mannheimia haemolytica is an opportunistic pathogen in cattle and the main bacterial agent in bovine respiratory disease. Despite its economic importance, few studies have characterized the genetic diversity of M. haemolytica, particularly from feedlots. Three genotyping techniques (BOX-PCR, (GTG)5-PCR and PFGE) were compared to discriminate M. haemolytica and strains from the family Pasteurellaceae. PFGE was the most discriminating and repeatable, although BOX-PCR was most accurate in clustering isolates together according to species.
Mannheimia haemolytica was isolated from nasal swab samples collected from cattle upon entry and exit from two feedlots in southern Alberta. These were characterized by PFGE and antimicrobial susceptibility using a disk-diffusion assay. Select gene determinants were screened for using PCR. PFGE analysis revealed the isolates to be highly diverse. Ten percent of the isolates exhibited resistance. At present, the development and spread of antimicrobial resistance in M. haemolytica observed within the feedlots examined appears to be low.xi, 116 leaves : ill. ; 29 cm
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Rodrigues, Ana Beatriz Bertoncello [UNESP]. "Características qualitativas e quantitativas do músculo Longissimus de bubalinos e bovinos terminados em confinamento." Universidade Estadual Paulista (UNESP), 2014. http://hdl.handle.net/11449/115605.
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000811614.pdf: 267019 bytes, checksum: a38c4eee0afe8f36692b23f7c2dd48f3 (MD5)O objetivo deste estudo foi avaliar as diferenças entre os parâmetros qualitativos, quantitativos e sensoriais do músculo Longissimus de bovinos e bubalinos. Foram utilizados animais das espécies bovina (Nelore) e bubalina (cruzados Mediterrâneo e Murrah). Os animais foram mantidos em confinamento comercial, por 102 dias, em baias coletivas, de acordo com a espécie, recebendo, no período de acabamento, 8,07% de proteína bruta e 72,10% de nutrientes digestíveis totais. O delineamento experimental foi inteiramente casualizado com 2 tratamentos (espécie animal) e 40 repetições. As médias foram comparadas pelo teste de Tukey, considerando o nível de significância de 5%, quando o teste F foi significativo. Os bovinos apresentaram melhor rendimento de carcaça (57,16 ± 1,42%), maior área de olho de lombo (59,38 ± 5,72 cm2), maior porcentagem de dianteiro (40,68 ± 1,30%), cortes mais pesados do dianteiro, menor oxidação lipídica (0,155 ± 0,033 mgMDA/kg), maior porcentagem de proteína (21,16 ± 0,97%) e cinzas (1,08 ± 0,06%), enquanto que os bubalinos obtiveram maior espessura de gordura subcutânea (13,85 ± 3,00 mm), menor perda no resfriamento (1,26 ± 0,15%), maior porcentagem de ponta de agulha (14,50 ± 0,57), cortes mais pesados do traseiro, menor porcentagem de perda por cocção (29,42 ± 3,04%), maior porcentagem de umidade (75,13 ± 0,89%), menor porcentagem de colágeno (4,81 ± 0,79%) e maior índice de fragmentação miofibrilar (79,91 ± 17,50). No painel sensorial somente a variável odor apresentou diferença (P<0,05) entre as espécies, sendo a carne bubalina com maior nota (7,30 ± 0,98 pontos). Conclui-se que a carne bovina diferencia da carne bubalina em termos de desempenho, características físicas e químicas. Porém a carne bubalina tem potencial para ...
The aim of this study was to evaluate the differences between qualitative, quantitative and sensory parameters of the Longissimus muscle of cattle and buffaloes. Were used cattle of Nellore breed and buffalo of Murrah and Mediterranean crossed. The animals were maintained on a commercial feedlot for 102 days in collective boxes according to species, getting in the finishing period, 8.07% crude protein and 72.10% total digestible nutrients. The experimental design was completely randomized with two treatments (species) and 40 repetitions. Means were compared by Tukey test, considering significance level of 5%, when the F test was significant. The cattle have higher carcass yield (57.16 ± 1.42%), a larger rib eye area (59.38 ± 5.72 cm2), higher percentage of forequarter (40.68 ± 1.30%), heavier cuts forequarter, lower lipid oxidation (0.155 ± 0.033 mgMDA/kg), increased percentage of protein (21.16 ± 0.97%) and ash (1.08 ± 0.06%) , while buffaloes showed greater fat thickness (13.85 ± 3.00 mm), smaller loss in cooling (1.26 ± 0.15%), higher percentage of spare rib (14.50 ± 0.57), heavier cuts of hindquarter, lower percentage cooking loss (29.42 ± 3.04%), higher percentage of moisture (75.13 ± 0.89%), lower percentage of collagen (4.81 ± 0.79%) and higher rate of myofibrillar fragmentation (79.91 ± 17.50). In sensory panel only odor variable showed differences (P < 0.05) between species, with the buffalo meat with highest score (7.30 ± 0.98 points). It is concluded that beef differs from buffalo meat in terms of performance, physical and chemical characteristics. But the buffalo meat has the potential to enter the consumer market
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Guarnieri, Filho Thomaz Antonio [UNESP]. "Utilização do meloxicam para reduzir respostas Inflamatórias em bovinos de corte transportados." Universidade Estadual Paulista (UNESP), 2015. http://hdl.handle.net/11449/126539.
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000833070.pdf: 276509 bytes, checksum: 168d0b0f9090ec30681d2c2cccd8a266 (MD5)Este experimento analisou os efeitos da administração do meloxicam nas respostas fisiológicas e no desempenho de bovinos na fase inicial do confinamento após serem transportados. Foram utilizados 84 bezerros Angus × Hereford, divididos por peso vivo (PV) no dia -10 do experimento e distribuídos em 21 baias de confinamento. Do d -10 ao d 0, todos os animais receberam uma dieta composta por feno de alfalfa a vontade e 2,4 kg/animal (base MS) de um concentrado a base de milho. No dia 0, todas as baias foram aleatoriamente atribuídas a receberem um dos seguintes tratamentos: 1) transporte por 1.440 km em um caminhão comercial e administração oral de meloxicam (1 mg/kg do PV) no carregamento (d 0), no descarregamento (d 1) e diariamente do d 2 ao d 7 no período inicial de confinamento (MEL; n = 7), 2) transporte e administração do tratamento nos mesmos dias do grupo MEL, porém com lactose monohidratada (1 mg/kg do PV) (TRANS; n = 7), 3) ausência de transporte e administração de lactose monohidratada (1 mg/kg do PV) nos mesmos dias dos tratamentos MEL e TRANS (CON; n = 7). Logo após o descarregamento (d 1), todos os animais dos tratamentos MEL e TRANS retornaram para suas respectivas baias para o período de 21 dias de confinamento, recebendo a mesma dieta oferecida do d -10 ao d 0. Nos dias 0 e 1, os tratamentos foram aplicados através de solução aquosa e administrados via oral, porém dos dias 2 ao 7, os tratamentos foram misturados no concentrado. Para o cálculo de ganho peso diário (GPD) foram utilizados as médias de ...
This experiment evaluated the effects of meloxicam administration on physiological and performance responses of transported cattle during feedlot receiving. Eighty-four Angus × Hereford steers were ranked by BW on d -10, and assigned to 21 dry lot pens. From d -10 to 0, pens were fed Alfalfa-grass hay ad libitum and 2.4 kg/steer daily (DM basis) of a corn-based concentrate. On d 0, pens were randomly assigned to: 1) transport for 1,440 km in a livestock trailer and oral administration of meloxicam (1 mg/kg of BW) at loading (d 0), unloading (d 1), and daily from d 2 to 7 of feedlot receiving (MEL; n = 7), 2) same transportation and treatment schedule of MEL, but oral administration of lactose monohydrate (1 mg/kg of BW) instead of meloxicam (TRANS; n = 7), or 3) no transport and oral administration of lactose monohydrate (1 mg/kg of BW) concurrently with treatment administration to MEL and TRANS (CON; n = 7). Upon arrival (d 1), MEL and TRANS steers returned to their pens for a 21-d feedlot receiving with the same diet offered from d -10 to 0. Treatments were administered to steers via oral drench on d 0 and 1, or mixed daily with the concentrate from d 2 to 7. Full BW was recorded prior to (d -2, -1, and 0) treatment application and at the end of experiment (d 20, 21, and 22) for ADG calculation. Daily DMI was recorded from d 1 to 21. Blood samples were collected on d 0, 1, 3, 5, 7, 10, 14, and 21. During the initial 7 d of feedlot receiving, hay and total DMI were reduced (P ≤ 0.03) in TRANS vs. CON and MEL, similar between CON and MEL (P ≥ 0.26), whereas concentrate DMI did not differ (P = 0.16) among ...
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Guarnieri, Filho Thomaz Antonio 1989. "Utilização do meloxicam para reduzir respostas Inflamatórias em bovinos de corte transportados /." Botucatu, 2015. http://hdl.handle.net/11449/126539.
Full textAbstract:
Orientador: Reinaldo Fernandes CookeBanca: José Luiz Moraes Vasconcelos
Banca: David W. Boahnet
Resumo: Este experimento analisou os efeitos da administração do meloxicam nas respostas fisiológicas e no desempenho de bovinos na fase inicial do confinamento após serem transportados. Foram utilizados 84 bezerros Angus × Hereford, divididos por peso vivo (PV) no dia -10 do experimento e distribuídos em 21 baias de confinamento. Do d -10 ao d 0, todos os animais receberam uma dieta composta por feno de alfalfa a vontade e 2,4 kg/animal (base MS) de um concentrado a base de milho. No dia 0, todas as baias foram aleatoriamente atribuídas a receberem um dos seguintes tratamentos: 1) transporte por 1.440 km em um caminhão comercial e administração oral de meloxicam (1 mg/kg do PV) no carregamento (d 0), no descarregamento (d 1) e diariamente do d 2 ao d 7 no período inicial de confinamento (MEL; n = 7), 2) transporte e administração do tratamento nos mesmos dias do grupo MEL, porém com lactose monohidratada (1 mg/kg do PV) (TRANS; n = 7), 3) ausência de transporte e administração de lactose monohidratada (1 mg/kg do PV) nos mesmos dias dos tratamentos MEL e TRANS (CON; n = 7). Logo após o descarregamento (d 1), todos os animais dos tratamentos MEL e TRANS retornaram para suas respectivas baias para o período de 21 dias de confinamento, recebendo a mesma dieta oferecida do d -10 ao d 0. Nos dias 0 e 1, os tratamentos foram aplicados através de solução aquosa e administrados via oral, porém dos dias 2 ao 7, os tratamentos foram misturados no concentrado. Para o cálculo de ganho peso diário (GPD) foram utilizados as médias de ...
Abstract: This experiment evaluated the effects of meloxicam administration on physiological and performance responses of transported cattle during feedlot receiving. Eighty-four Angus × Hereford steers were ranked by BW on d -10, and assigned to 21 dry lot pens. From d -10 to 0, pens were fed Alfalfa-grass hay ad libitum and 2.4 kg/steer daily (DM basis) of a corn-based concentrate. On d 0, pens were randomly assigned to: 1) transport for 1,440 km in a livestock trailer and oral administration of meloxicam (1 mg/kg of BW) at loading (d 0), unloading (d 1), and daily from d 2 to 7 of feedlot receiving (MEL; n = 7), 2) same transportation and treatment schedule of MEL, but oral administration of lactose monohydrate (1 mg/kg of BW) instead of meloxicam (TRANS; n = 7), or 3) no transport and oral administration of lactose monohydrate (1 mg/kg of BW) concurrently with treatment administration to MEL and TRANS (CON; n = 7). Upon arrival (d 1), MEL and TRANS steers returned to their pens for a 21-d feedlot receiving with the same diet offered from d -10 to 0. Treatments were administered to steers via oral drench on d 0 and 1, or mixed daily with the concentrate from d 2 to 7. Full BW was recorded prior to (d -2, -1, and 0) treatment application and at the end of experiment (d 20, 21, and 22) for ADG calculation. Daily DMI was recorded from d 1 to 21. Blood samples were collected on d 0, 1, 3, 5, 7, 10, 14, and 21. During the initial 7 d of feedlot receiving, hay and total DMI were reduced (P ≤ 0.03) in TRANS vs. CON and MEL, similar between CON and MEL (P ≥ 0.26), whereas concentrate DMI did not differ (P = 0.16) among ...
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Rodrigues, Ana Beatriz Bertoncello. "Características qualitativas e quantitativas do músculo Longissimus de bubalinos e bovinos terminados em confinamento /." Jaboticabal, 2014. http://hdl.handle.net/11449/115605.
Full textAbstract:
Orientador: Hirasilva BorbaBanca: Jane Maria Bertocco Ezequiel
Banca: Cristiana Andrighetto
Resumo: O objetivo deste estudo foi avaliar as diferenças entre os parâmetros qualitativos, quantitativos e sensoriais do músculo Longissimus de bovinos e bubalinos. Foram utilizados animais das espécies bovina (Nelore) e bubalina (cruzados Mediterrâneo e Murrah). Os animais foram mantidos em confinamento comercial, por 102 dias, em baias coletivas, de acordo com a espécie, recebendo, no período de acabamento, 8,07% de proteína bruta e 72,10% de nutrientes digestíveis totais. O delineamento experimental foi inteiramente casualizado com 2 tratamentos (espécie animal) e 40 repetições. As médias foram comparadas pelo teste de Tukey, considerando o nível de significância de 5%, quando o teste F foi significativo. Os bovinos apresentaram melhor rendimento de carcaça (57,16 ± 1,42%), maior área de olho de lombo (59,38 ± 5,72 cm2), maior porcentagem de dianteiro (40,68 ± 1,30%), cortes mais pesados do dianteiro, menor oxidação lipídica (0,155 ± 0,033 mgMDA/kg), maior porcentagem de proteína (21,16 ± 0,97%) e cinzas (1,08 ± 0,06%), enquanto que os bubalinos obtiveram maior espessura de gordura subcutânea (13,85 ± 3,00 mm), menor perda no resfriamento (1,26 ± 0,15%), maior porcentagem de ponta de agulha (14,50 ± 0,57), cortes mais pesados do traseiro, menor porcentagem de perda por cocção (29,42 ± 3,04%), maior porcentagem de umidade (75,13 ± 0,89%), menor porcentagem de colágeno (4,81 ± 0,79%) e maior índice de fragmentação miofibrilar (79,91 ± 17,50). No painel sensorial somente a variável odor apresentou diferença (P<0,05) entre as espécies, sendo a carne bubalina com maior nota (7,30 ± 0,98 pontos). Conclui-se que a carne bovina diferencia da carne bubalina em termos de desempenho, características físicas e químicas. Porém a carne bubalina tem potencial para ...
Abstract: The aim of this study was to evaluate the differences between qualitative, quantitative and sensory parameters of the Longissimus muscle of cattle and buffaloes. Were used cattle of Nellore breed and buffalo of Murrah and Mediterranean crossed. The animals were maintained on a commercial feedlot for 102 days in collective boxes according to species, getting in the finishing period, 8.07% crude protein and 72.10% total digestible nutrients. The experimental design was completely randomized with two treatments (species) and 40 repetitions. Means were compared by Tukey test, considering significance level of 5%, when the F test was significant. The cattle have higher carcass yield (57.16 ± 1.42%), a larger rib eye area (59.38 ± 5.72 cm2), higher percentage of forequarter (40.68 ± 1.30%), heavier cuts forequarter, lower lipid oxidation (0.155 ± 0.033 mgMDA/kg), increased percentage of protein (21.16 ± 0.97%) and ash (1.08 ± 0.06%) , while buffaloes showed greater fat thickness (13.85 ± 3.00 mm), smaller loss in cooling (1.26 ± 0.15%), higher percentage of spare rib (14.50 ± 0.57), heavier cuts of hindquarter, lower percentage cooking loss (29.42 ± 3.04%), higher percentage of moisture (75.13 ± 0.89%), lower percentage of collagen (4.81 ± 0.79%) and higher rate of myofibrillar fragmentation (79.91 ± 17.50). In sensory panel only odor variable showed differences (P < 0.05) between species, with the buffalo meat with highest score (7.30 ± 0.98 points). It is concluded that beef differs from buffalo meat in terms of performance, physical and chemical characteristics. But the buffalo meat has the potential to enter the consumer market
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Denholm, Rachael Ann. "Changes in Antimicrobial Resistance from 1994 to 2011 and Exploring Farm Management Practices Associated with Antimicrobial Resistance in Salmonella on U.S. Beef Feedlots." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1492702064126336.
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Dantas, Ariane [UNESP]. "Idade à puberdade e desenvolvimento da glândula mamária de cordeiras sob baixa e alta velocidades de crescimento." Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/96650.
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dantas_a_me_botfmvz.pdf: 285512 bytes, checksum: 02e43a11479ebbef1e68d1c1aa53dc28 (MD5)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Este estudo teve como objetivo avaliar a idade à puberdade, a dinâmica corporal e o desempenho de cordeiras Bergamácia submetidas a dietas para baixa e alta velocidades de crescimento, até 1 ano de idade. Vinte cordeiras foram mantidas confinadas (duas por baia) durante todo o período experimental recebendo dois tipos de dietas formuladas para obtenção de ganho de peso médio diário: 1) Baixo (180 gramas); 2) Alto (300 gramas). O experimento foi dividido em duas fases, sendo a primeira o período compreendido até as cordeiras atingirem 30 kg; e a segunda fase a partir de 30 kg até 1 ano de idade. Para avaliação da dinâmica do desenvolvimento corporal, a cada 14 dias os animais foram pesados, determinado o escore de condição corporal e registradas medidas biométricas. A partir do 5º mês de idade foi introduzido, em cada grupo experimental, um macho vasectomizado para realizar a detecção do estro e determinar a idade à puberdade e o intervalo entre os dois primeiros estros de cada cordeira. Foram encontradas diferenças (P˂0,05) entre os tratamentos para ganho de peso médio diário, escore de condição corporal e para as medidas biométricas. Não houve diferença (P>0,05) para idade à puberdade. Verificou-se que os tratamentos baixo e alto proporcionaram desempenhos adequados, porém não revelaram diferentes respostas a idade à puberdade. A dieta para alta velocidade de crescimento proporcionou pesos superiores e melhor escore de condição corporal nas duas fases experimentais
This study aimed to evaluate the age at puberty, body dynamics and performance of Bergamasca lambs submitted to diets for low and high growth rates, up to 1 year old. Twenty lambs were kept confined (two per stall) throughout the experimental period getting two types of diets to obtain average daily weight gain: 1) Low (180 grams) 2) High (300 grams). The experiment was divided into two stages, the first was the period until lambs reached 30 kg, and the second phase with the lambs weighting from 30 kg until they reach one 1 year old. To assess the dynamics of body development, every 14 days the animals were weighed, the body condition score was determined and biometrics measurements were registered. From the 5th month of age was introduced in each experimental group, a vasectomized male to perform the detection of estrus and to determine the age at puberty and interval between the first two estrous of each lamb. Differences were found (P˂0.05) among treatments for average daily weight gain, body condition score and biometric measurements. There was no difference (P>0.05) for age at puberty. It has been found that low and high treatments yielded adequate performance, but did not show different responses in age at puberty. A high growth rate diet yielded higher body weights and better body condition score in both phases