To see the other types of publications on this topic, follow the link: Feedlots.
Journal articles on the topic 'Feedlots'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Feedlots.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Shiddieqy, M. I., M. N. Rofiq, and Y. Widiawati. "Sustainable manure management systems in beef cattle feedlots." IOP Conference Series: Earth and Environmental Science 1114, no. 1 (December 1, 2022): 012049. http://dx.doi.org/10.1088/1755-1315/1114/1/012049.
Full textAbstract:
Abstract The population of feeder cattle in feedlots is not significant compared to the total cattle population. However, the intensive management system in feedlots has negative impact on the environment. Currently, there is limited information on manure handling in the beef cattle feedlots in Indonesia. This study aimed to describe the manure management system of surveyed feedlots in Lampung Province, Indonesia. The method of this study was descriptive with field observation and survey in three feedlots in Lampung. Data related to manure management were collected on the farm, while the data on manure management systems, animal characteristics, and housing system were gathered from questionnaires in the survey. The data were described and analysed using comparison with previous studies. The result showed that the surveyed feedlots utilize manure as organic fertilizer. The manure and effluent were treated and pumped onto forage fields. One feedlot company with an advanced manure treatment facility has implemented a sustainable manure management strategy. The study suggests further research to measure the carbon cycle for several types of feedlot’s manure management systems as an environmental product declares of beef cattle production in Indonesia.
2
Bai, Mei, Trevor Coates, Julian Hill, Thomas K. Flesch, David W. T. Griffith, Matthew Van der Saag, Des Rinehart, and Deli Chen. "Measurement of Long-Term CH4 Emissions and Emission Factors from Beef Feedlots in Australia." Atmosphere 14, no. 9 (August 28, 2023): 1352. http://dx.doi.org/10.3390/atmos14091352.
Full textAbstract:
One of the major challenges for the Australian feedlot and meat sectors is to have accurate and robust long-term greenhouse gas (GHG) emissions data. Long-term measurements of methane (CH4) emissions (2015–2017) were made at two Australian beef feedlots having different climates, cattle types, and management practices. Emissions were measured using the inverse-dispersion model (IDM) micrometeorological technique, using CH4 concentrations measured at the feedlots with a closed-path Fourier transform infrared spectroscopic technique (CP-FTIR). The emissions data were used to evaluate methods used by the Department of Climate Change, Energy, the Environment and Water to estimate CH4 emissions from feedlots in Australian national inventory calculations. Expressed as a CH4 yield (emissions per unit dry matter intake, DMI), the two feedlots had emissions of 13.1 and 18.9 g CH4 kg−1 DMI. The lower-emitting feedlot had emissions that were 30% lower than the national inventory calculations based on feed intakes, while the second feedlot had emissions that were similar to the inventory calculations. The accurate quantification of emissions from feedlots, as demonstrated as part of this study, is important for validating the national accounting methods and therefore the sector’s GHG emissions profile.
3
Estima-Silva, Pablo, Plínio A. Oliveira, Fabio Raphael P. Bruhn, Haide Valeska Scheid, Lucas S. Marques, Luiza S. Ribeiro, and Ana Lucia Schild. "Causes of death of beef cattle raised in feedlots." Pesquisa Veterinária Brasileira 40, no. 5 (May 2020): 333–39. http://dx.doi.org/10.1590/1678-5150-pvb-6539.
Full textAbstract:
ABSTRACT: The causes of death of cattle kept in pre-export feedlots (PEFs) and in feedlot for finishing for slaughter are described. Two studies were conducted: a retrospective study of mortality cases in feedlots from 2000 to 2017 registered at the “Laboratório Regional de Diagnóstico” of the “Faculdade de Veterinária” of the “Universidade Federal de Pelotas”; and a prospective study from January 2018 to August 2019, following up 22 feedlots for finishing and six PEFs for the export of live cattle. From January 2000 to August 2019 samples of 150 cases of diseases that affected feedlot cattle were received from 22 feedlots for finishing and 115 of the six PEFs followed. Mortality considering all diagnosed diseases was significantly higher in feedlots for finishing (p<0.05), than in PEFs for the export of live cattle, of 1% and 0.12%, respectively. Diseases of the digestive system were the most important causes, of death in feedlots regardless of its purpose. Acidosis presented the highest mortality rates both in feedlot for finishing (3.33%) as in PEFs for export (0.95%). In all cases the disease occurred due to failure in the adaptation of animals to the ingestion of concentrated foods. Bovine tick fever and pneumonia presented mortality rates of 0.13% and 0.09%, respectively in PEFs. In the feedlot for finishing seneciosis was the second cause of death due to cattle coming from areas with high infestation by the plant. In the present study, it was possible to identify the main diseases that occur in cattle feedlots for finishing or for the export of live animals in the southern region of Rio Grande do Sul. These diseases are known in other systems of cattle breeding and can be prevented or controlled through management, chemoprophylaxis or vaccination, minimizing losses due to mortality.
4
Bernardes, Thiago, and Thais Castro. "PSXII-12 Silages and roughage sources in the Brazilian beef feedlots." Journal of Animal Science 97, Supplement_3 (December 2019): 411. http://dx.doi.org/10.1093/jas/skz258.815.
Full textAbstract:
Abstract The aim of this survey was to identify silages and roughage sources adopted in the beef finishing diets. Eighty-two feedyards, located in 10 states, were surveyed from January to March 2019 for their feeding practices. Feedlot owners and nutritionists were interviewed by using a common survey form. The form consisted of 5 questions, including feedlot location, feedlot capacity and the number of animals serviced yearly, breed, silages and roughage sources, and roughage: concentrate ratio. Results were tabulated in an Excel spreadsheet for each feedlot. The number of responses per question, and the mean, minimum value, maximum value, and mode (most frequently occurring value) were calculated. Feedlot capacity ranged from 300 to 35,000 (mode = 3,000) and cattle serviced yearly per feedlot ranged from 400 to 90,000 (mode = 6,000). Nellore breed and crossbreed represented 74 and 26% % of finished animals, respectively. Roughage: concentrate ratio ranged from 40: 60 to 10: 90. Thirty-five percent of feedlots adopted 20: 80 ratio, followed by 15: 85 (16%) and 10: 90 (16%) ratios. Whole-plant corn silage was the most common roughage source (57%; Figure 1), followed by sugarcane bagasse (17%), tropical grass silages (16%), and whole-plant sorghum silage (11%). Nutritionists also cited hay (9%), sugarcane silage (5%), and fresh sugarcane (4%) as roughage sources. High-moisture corn, snaplage (grain, cob, husk, shank), and reconstituted grain corn were used by 20, 11, and 1% of feedlots, respectively. Reconstituted grain sorghum was included in 4% of the diets. Thus, 36% of feedlots adopted grain silages (corn and sorghum) in the diets. Overall, Brazilian feedlots have used high-energy finishing diets and corn is the most widely grown crop for silage. Feedlots have shown interest in using grain silages to maximize starch digestion, especially because Brazil grows flint corn and silage machinery industry has made available new equipment.
5
de Andrade, Thiago Sérgio, Tiago Zanett Albertini, Luís Gustavo Barioni, Sérgio Raposo de Medeiros, Danilo Domingues Millen, Antônio Carlos Ramos dos Santos, Rodrigo Silva Goulart, and Dante Pazzanese Duarte Lanna. "Perception of consultants, feedlot owners, and packers regarding management and marketing decisions on feedlots: a national survey in Brazil (Part II)." Canadian Journal of Animal Science 100, no. 4 (December 1, 2020): 759–70. http://dx.doi.org/10.1139/cjas-2019-0220.
Full textAbstract:
Research interviews with agribusiness professionals are carried out in several countries for updating and developing technologies. This study aimed to investigate the perception of Brazilian feeders regarding management and marketing tools used in the feedlot industry. Interviews were conducted with groups: nutritionist-consultants (n = 23), feedlot owners (n = 21), and packer-owned feedlots (n = 8). Roughly 58% of the interviewees worked with two cycles of animals per year. Roughly 80% of animals on feedlots were males, with 73% of the respondents having fed only intact males and 75% of the animals were Nellore breed. Among the criteria used for pen formation, weight was the most common (75%). The use of computational tools for feedlot management (71%) and diet formulation (69%) were found to be common, although interviewees did not use any software to characterize feeder animals. In 44% of the respondent feedlots, animals that reached the desired weight and degree of finish were removed for slaughter, whereas the unfinished animals remained in the same pen. We found that a need, therefore, exists to develop efficient strategies for forming homogeneous pens upon animal entry onto feedlots, and maintaining homogenous pens upon the exit of animals for slaughter.
6
Baber, Jessica, Jason Sawyer, Ben Holland, Kendall Karr, Alyssa Word, and Tryon Wickersham. "146 Net protein contribution of feedlots from 2006 to 2017." Journal of Animal Science 97, Supplement_3 (December 2019): 146. http://dx.doi.org/10.1093/jas/skz258.299.
Full textAbstract:
Abstract Feedlot efficiency has increased as technologies are adopted and new feed ingredients, generally byproducts, have become available and readily incorporated. To evaluate the effect of diet changes and feedlot production over time on net protein contribution (NPC), a deterministic NPC model was used. Lot level production data from 2006 to 2017 for 8 commercial feedlots was used. Ingredient and nutrient composition were collected for a representative starter and finisher diet fed for each year and feedlot combination. Net protein contribution was calculated by multiplying the ratio of human-edible protein (HeP) in beef produced to HeP in feed by the protein quality ratio (PQR). A NPC >1 indicates a production system is positively contributing to meeting human protein requirements, whereas a NPC < 1 indicates competition with humans for HeP. Regressing NPC on year evaluated temporal change in NPC, and feedlots were categorized as increasing (INC; slope > 0) or constant (CON; slope = 0). Four feedlots were categorized as INC and 4 were CON. A common slope was estimated for CON and INC for PQR (P ≥ 0.79). Slopes of INC and CON differed for byproduct and cereal grain inclusion (P ≤ 0.01). Feedlots categorized as INC reduced HeP consumed by 2.39% per year, but CON feedlots did not (0.28%). Cattle received and shipped by INC were lighter than CON cattle (P < 0.01). Both feedlot types tended to improve HeP gained (0.1 kg per year; P = 0.10). Differences in slope for INC and CON were observed for conversion efficiency of HeP (P < 0.01). Net protein contribution increased 0.027 units per year for INC (P < 0.01) and was 0.94 in 2017. Net protein contribution by the feedlot sector increased from 2006 to 2017 as a result of using less human-edible feeds to produce human-edible beef protein.
7
Fike, Karol E., and Pete T. Anderson. "36 Kansas State University Feedlot Boot Camp and Teaching Program: Growing Student Interest and Engagement in the Feedlot Industry." Journal of Animal Science 100, Supplement_2 (April 12, 2022): 121–22. http://dx.doi.org/10.1093/jas/skac064.206.
Full textAbstract:
Abstract The Kansas State University Collegiate Feedlot Boot Camp and Teaching Program was initiated in January 2019 with the goal to develop student knowledge, skills, and professional relationships in feedlot management to help meet critical need for trained professionals in the feedlot industry. Allied industry supporters including feedlot nutrition and veterinary consultants, pharmaceutical companies, and lenders, as well as feedlot owners/managers and the Kansas State University Department of Animal Sciences and Industry collaborated to develop, sponsor, and offer the program, which is offered at no cost to students who are selected. Specific objectives are to train students in aspects of feedlot management through a 4-d comprehensive “Boot Camp” at Western Kansas feedlots, enhance students’ likelihood of participating in feedlot internships, and cultivate students’ vision of potential career paths within the industry. Boot Camp topics include cattle health, feeding and nutrition, feedlot design and maintenance, and the business of cattle feeding. A networking dinner brings students and feedlot managers together to facilitate students gaining internship and full-time employment with feedlots. Following the January Boot Camp, students share individual presentations on relevant industry topics. Presentations are recorded and shared with feedlot managers to further engagement between students and feedlot managers. Later in the spring semester students also participate in a half-day cattle processing experience at a feedlot near Kansas State to provide additional insight and experience with feedlot health management. Limited to 20 participants per year, 59 undergraduate students have completed the program. When surveyed, over 98% (58/59) of student participants agreed with the statement “My interest in pursuing an internship and (or) career in the feedlot industry grew as a result of this Boot Camp.” Approximately 50% of students participated in feedlot internships or earned full-time jobs working in feedlots. Ranging from students with little to no experience with feedlots to being raised on beef cow-calf or feedlot operations, progress is being made in growing student interest and awareness of career opportunities in the feedlot industry.
8
Baber, Jessica R., Jason E. Sawyer, Ben P. Holland, Kendall J. Karr, Alyssa B. Word, and Tryon A. Wickersham. "Net protein contribution of beef feedlots from 2006 to 2017." Translational Animal Science 3, no. 4 (July 1, 2019): 1575–84. http://dx.doi.org/10.1093/tas/txz142.
Full textAbstract:
Abstract: Feedlot efficiency increases as technologies are adopted and new feed ingredients, especially byproducts, become available and incorporated into diets. Byproduct availability increased in response to the renewable fuels standard of 2005, creating substantial amounts of feedstuffs best used by ruminants. Cereal grains have been partially replaced with human-inedible byproducts, as they provide comparable levels of energy in cattle diets. To evaluate the effects of changes in diet and feedlot production practices on net protein contribution (NPC) and human-edible protein conversion efficiency (HePCE) across time, a deterministic NPC model was used. NPC was assessed for the feedlot industry using lot level production data from 2006 to 2017 for eight commercial feedlots. Ingredient and nutrient composition was collected for a representative starter and finisher diet fed for each year from each feedlot. NPC was calculated by multiplying human-edible protein (HeP) in beef produced per unit of HeP in feed by the protein quality ratio (PQR). Systems with NPC >1 positively contribute to meeting human protein requirements; NPC < 1 indicates competition with humans for HeP. NPC was regressed on year to evaluate temporal change in NPC. Feedlots were categorized as increasing NPC (INC; slope > 0) or constant NPC (CON; slope = 0) according to regression parameter estimates. Four feedlots were categorized as INC and four were CON. The rate of change in PQR was similar for CON and INC (P ≥ 0.79), although rates of change among INC and CON differed for byproduct and cereal grain inclusion (P ≤ 0.01) across years evaluated. Feedlots categorized as INC reduced HeP consumed by 2.39% per year, but CON feedlots did not reduce HeP consumed each year (0.28%). Cattle received and shipped by INC were lighter than those in CON feedlots (P < 0.01). Across years, INC produced more HeP (20.9 vs. 19.2 kg/hd) than CON (P < 0.01), and both feedlot types tended to improve HeP gained over time (0.1 kg per year; P = 0.10). Differences in slope over time for INC and CON were observed for conversion efficiency of HeP (P < 0.01). NPC increased 0.027 units per year for INC (P < 0.01) and was 0.94 in 2017. NPC by the feedlot sector improved from 2006 to 2017, decreasing the amount of human-edible feeds required to produce more high-quality protein from beef.
9
Bernardes, Thiago, Thais Castro, and Matheus Da Luz. "PSVIII-B-11 Grain Processing Methods and Fiber Sources in the Brazilian Beef Feedlots." Journal of Animal Science 100, Supplement_3 (September 21, 2022): 315–16. http://dx.doi.org/10.1093/jas/skac247.575.
Full textAbstract:
Abstract The aim of this survey was to identify grain processing techniques and fiber sources adopted in the beef finishing diets. One hundred and forty-nine feedyards, located in 10 states, were surveyed from March 2020 to February 2021 for their feeding practices. Feedlot owners and nutritionists were interviewed by using a common survey form. The form consisted of 5 questions, including feedlot location, feedlot capacity and the number of animals serviced yearly, breed, grain processing techniques and roughage sources, and roughage: concentrate ratio. Results were tabulated in an Excel spreadsheet for each feedlot. The number of responses per question, and the mean, minimum value, maximum value, and mode (most frequently occurring value) were calculated. Feedlot capacity ranged from 300 to 40,000 (mode = 3,000) and cattle serviced yearly per feedlot ranged from 400 to 90,000 (mode = 6,000). Nellore breed and crossbreed represented 67 and 33% % of finished animals, respectively. Roughage: concentrate ratio ranged from 40: 60 to 10: 90. Thirty-four percent of feedlots adopted 20: 80 ratio, followed by 25: 75 (17.5%) and 15: 85 (14%) ratios. High-moisture corn, snaplage (grain, cob, husk, and shank), and reconstituted grain corn were used by 21, 12, and 6.7% of feedlots, respectively. Reconstituted grain sorghum was included in 4% of the diets. Thus, 43.7% of feedlots adopted grain silages in the diets. Whole-plant corn silage was the most common roughage source (59.5%), followed by sugarcane bagasse (16%), tropical grass silages (14%), and whole-plant sorghum silage (13%). Nutritionists also cited hay (8%), sugarcane silage (6%), and fresh sugarcane (3%) as roughage sources. Overall, Brazilian feedlots have used ensiling as the most important method to process grains (corn and sorghum), especially because silage machinery industry has made available new equipment. Whole-plant corn silage is the most common fiber source.
10
Malafaia, Pedro, Tiago Alvin Lima Granato, Rogério Magnoli Costa, Vinícius Carneiro de Souza, Diogo Fleury Azevedo Costa, and Carlos Hubinger Tokarnia. "Major health problems and their economic impact on beef cattle under two different feedlot systems in Brazil." Pesquisa Veterinária Brasileira 36, no. 9 (September 2016): 837–43. http://dx.doi.org/10.1590/s0100-736x2016000900008.
Full textAbstract:
Abstract: This study aimed to describe the diagnosis of health problems and to evaluate the cost of their treatment for cattle raised in feedlots to be slaughtered or to be sold as sires for cow-calf systems. Bovine respiratory disease and digestive disorders were the main problems diagnosed in the feedlot for slaughter; the cost for treatment was high, accounting for 9.7 to 20.9 kg of live weight (LW) or the equivalent of 7 to 15% of total LW gained over the days on feed. Due to the high intake of starch-rich concentrate, rumen and fecal pH was lower, whilst rumen osmolarity and blood lactate were higher in cattle fed for slaughter. Cattle affected by digestive disorders spent on average four additional days in the feedlot. Diseases and cost of treatments were associated with lower average daily gain and considerable economic losses. Health problems commonly observed in the feedlots for slaughter were not observed in the feedlots for males to be sold as sires. The most likely reason for this observation was the more careful nutrition and prophylactic health management in sire production systems, which produce animals of much higher selling price. Results from this study suggest that health problems found in feedlots for slaughter may not only reduce animal productivity and profitability, but also the welfare of the animals. The systemic understaffing of livestock cattle workers and veterinarians in large feedlots in Brazil results in under reporting of diseases and lack to understand epidemiological context and disease prevention.
11
Antaki-Zukoski, Elizabeth M., Xunde Li, Bruce Hoar, John M. Adaska, Barbara A. Byrne, and Edward R. Atwill. "Understanding the transmission dynamics of Escherichia coli O157:H7 super-shedding infections in feedlot cattle." PeerJ 9 (December 20, 2021): e12524. http://dx.doi.org/10.7717/peerj.12524.
Full textAbstract:
Background The presence of Escherichia coli O157:H7 (E. coli O157:H7) super-shedding cattle in feedlots has the potential to increase the overall number (bio-burden) of E. coli O157:H7 in the environment. It is important to identify factors to reduce the bio-burden of E. coli O157 in feedlots by clarifying practices associated with the occurrence of super-shedders in feedlot cattle. Methods The objective of this study is to (1) identify host, pathogen, and management risk factors associated with naturally infected feedlot cattle excreting high concentrations of E. coli O157:H7 in their feces and (2) to determine whether the ingested dose or the specific strain of E. coli O157:H7 influences a super-shedder infection within experimentally inoculated feedlot cattle. To address this, (1) pen floor fecal samples and herd parameters were collected from four feedlots over a 9-month period, then (2) 6 strains of E. coli O157:H7, 3 strains isolated from normal shedder steers and 3 strains isolated from super-shedder steers, were inoculated into 30 one-year-old feedlot steers. Five steers were assigned to each E. coli O157:H7 strain group and inoculated with targeted numbers of 102, 104, 106, 108, and 1010 CFU of bacteria respectively. Results In the feedlots, prevalence of infection with E. coli O157:H7 for the 890 fecal samples collected was 22.4%, with individual pen prevalence ranging from 0% to 90% and individual feedlot prevalence ranging from 8.4% to 30.2%. Three samples had E. coli O157:H7 levels greater than 104 MPN/g feces, thereby meeting the definition of super-shedder. Lower body weight at entry to the feedlot and higher daily maximum ambient temperature were associated with increased odds of a sample testing positive for E. coli O157:H7. In the experimental inoculation trial, the duration and total environmental shedding load of E. coli O157:H7 suggests that the time post-inoculation and the dose of inoculated E. coli O157:H7 are important while the E. coli O157:H7 strain and shedding characteristic (normal or super-shedder) are not. Discussion Under the conditions of this experiment, super-shedding appears to be the result of cattle ingesting a high dose of any strain of E. coli O157:H7. Therefore strategies that minimize exposure to large numbers of E. coli O157:H7 should be beneficial against the super-shedding of E. coli O157:H7 in feedlots.
12
Fossler, Charles. "NAHMS 2021 Feedlot study." American Association of Bovine Practitioners Conference Proceedings, no. 55 (July 17, 2023): 19–20. http://dx.doi.org/10.21423/aabppro20228589.
Full textAbstract:
The National Animal Health Monitoring System (NAHMS) conducts national studies on the health and health management of U.S. domestic livestock populations. In the NAHMS Feedlot 2021 study, for feedlots that placed cattle not born and raised on the operation slightly over half of cattle placed (51.1%) came directly from a cow-calf operation or a stocker or backgrounder operation, while 41.2% came from a sale barn. Of the cattle placed in 2020, 85.1% were placed with the intention of meeting no specific marketing claims, 0.5% of cattle were placed to meet certified organic claims, 8.4% were placed to meet no or limited antibiotic use claims, and 10.2% were placed to meet no hormone use claims. About three-fourths (73.1%) of feedlots used antibiotics in any form in 2020. Of these feedlots: 22.4% gave injectable antibiotics to cattle as a group; 67.6% gave injectable antibiotics to sick cattle; 42.8% gave antibiotics in feed; and 4.5% gave antibiotics in water. Most feedlots (85.1%) used a veterinarian in 2020. About two-thirds of feedlots (64.2%) felt that on January 1, 2017, they had all the resources necessary to manage the Veterinary Feed Directive (VFD) rule change.
13
Taylor, Donald C., and Diane H. Rickerl. "Feedlot manure nutrient loadings on South Dakota farmland." American Journal of Alternative Agriculture 13, no. 2 (June 1998): 61–68. http://dx.doi.org/10.1017/s0889189300007670.
Full textAbstract:
AbstractA key determinant of whether livestock manure is an asset or liability for agricultural producers and for society more generally is the amount produced relative to the nearby farmland area to which it can be economically transported for application. The objectives of this study are to estimate manure N and P loadings on the cropland and rangeland associated with 78 feedlot farm operations in South Dakota and to determine if they are greater for larger feedlots.A substantial fraction of the feedlot operators studied apply plant-available N and P in livestock manure at rates that exceed crop and grass fertility requirements, and intensity of manure nutrient loadings on cropland is strongly and positively related to feedlot size. These findings raise a warning regarding possible nonpoint-source pollution of vulnerable water resources from manure produced by fed cattle in larger feedlots.
14
Borshch, Oleksandr O., Sergiy Ruban, Oleksandr V. Borshch, Mykhailo Matvieiev, Vasyl Prudnikov, Oleksandr Sobolev, Vita Bilkevych, and Maksym Fedorchenko. "Cow behaviour and milk yield during different categories temperature-humidity indices." Revista de Investigaciones Veterinarias del Perú 35, no. 1 (February 29, 2024): e25305. http://dx.doi.org/10.15381/rivep.v35i1.25305.
Full textAbstract:
The goal of this investigation was to study the influence of different values of Temperature-Humidity index (THI) on the duration of lying down and feed consumption, productivity, and heat production by dairy cows in two variants of feedlots (with and without shelters). The study was conducted from February 2007 to early August 2021 in the central part of Ukraine (Kyiv region) in different periods of THI. This index was divided into three categories: 1) 66–71: normal (14 days); 2) 72–79: alert (11 days); 3) >80: dangerous (9 days). Two variants of feedlots were selected: Open feedlot with shelters and open feedlot without shelters. The largest increase in values of THI affecting the cows was observed in open feedlots without shelters. There, in alert and danger periods duration of feed consumption decreased by 8.0 and 23.1 min, lying down by 17 and 38 min, productivity by 2.3 kg (or 8.77%) and 3.6 kg (or 13.74%), energy consumption by 4.7 and 9.6 MJ, respectively, in comparison to normal period.
15
Pinto, Ana C. J., and Danilo D. Millen. "Nutritional recommendations and management practices adopted by feedlot cattle nutritionists: the 2016 Brazilian survey." Canadian Journal of Animal Science 99, no. 2 (June 1, 2019): 392–407. http://dx.doi.org/10.1139/cjas-2018-0031.
Full textAbstract:
The feedlot industry in Brazil is still evolving, and some nutritional management recommendations adopted by nutritionists changes from year to year. The main objective of this survey was to provide a snapshot of current nutritional management practices adopted in Brazilian feedlots. The 33 nutritionists surveyed were responsible for approximately 4 228 254 animals. Corn remained as the primary source of grain used in feedlot diets by the participants, whereas fine grinding was the primary grain processing method. Corn silage was the primary roughage source indicated by nutritionists, and for the first time, physically effective neutral detergent fiber was the preferred fiber analysis method. The average dietary fat recommended was 50 g kg−1 of dry matter, which is about 10% higher than values reported in previous surveys. The use of truck-mounted mixers increased, which may have increased the percentage of feedlots using programmed feed delivery per pen, allowing the increase of energy content of finishing diets. Feedlots did not increase their capacity and nutritionists reported an improvement in feeding management. Results reported in the current study provide a baseline that can be used to improve practices and aid in the development of feedlot industry in Brazil and similar tropical climates.
16
Slayi, Mhlangabezi, Leocadia Zhou, and Ishmael Festus Jaja. "Constraints Inhibiting Farmers’ Adoption of Cattle Feedlots as a Climate-Smart Practice in Rural Communities of the Eastern Cape, South Africa: An In-Depth Examination." Sustainability 15, no. 20 (October 12, 2023): 14813. http://dx.doi.org/10.3390/su152014813.
Full textAbstract:
The adoption of climate-smart agricultural practices is crucial for enhancing resilience to climate change in rural communities, particularly in developing regions like the Eastern Cape, South Africa. This study provides an in-depth examination of the factors constraining farmers’ adoption of cattle feedlots as a climate-smart practice in the rural communities of the Eastern Cape. The research aims to identify the barriers and challenges that hinder the widespread adoption of cattle feedlots and understand the underlying factors contributing to the farmers’ decision-making processes. The study employed a mixed-methods approach, including surveys and interviews, to gather data from 250 farmers in rural communities of the Eastern Cape. The data were analyzed using regression analysis and thematic analysis to identify the key constraints inhibiting the adoption of cattle feedlots as a climate-smart strategy. The findings revealed several significant constraints that farmers faced in adopting cattle feedlots. Financial limitations, including limited access to credit and lack of financial resources, emerged as critical barriers. Infrastructure and resource constraints, such as inadequate water supply and electricity, hindered adoption. Knowledge and skills gaps, cultural and social factors, market limitations, and environmental considerations further contributed to the constraints experienced by farmers. To address these constraints, the study proposes interventions to promote the adoption of cattle feedlots as a climate-smart practice. These interventions include improving access to affordable financing options, providing capacity-building programs on feedlot management and climate-smart practices, disseminating information on feedlot benefits and best practices, developing the necessary infrastructure, strengthening market linkages, and creating a supportive policy environment. However, it is important to note the study’s limitations, such as the small sample size and the cross-sectional nature of the data, which may limit the generalizability of the findings. Further research is needed to validate and expand upon these findings in a broader context. Overall, this study provides valuable insights into the factors constraining farmers’ adoption of cattle feedlots as a climate-smart practice in the rural communities of the Eastern Cape, South Africa.
17
Vidovic, Sinisa, and Darren R. Korber. "Prevalence of Escherichia coli O157 in Saskatchewan Cattle: Characterization of Isolates by Using Random Amplified Polymorphic DNA PCR, Antibiotic Resistance Profiles, and Pathogenicity Determinants." Applied and Environmental Microbiology 72, no. 6 (June 2006): 4347–55. http://dx.doi.org/10.1128/aem.02791-05.
Full textAbstract:
ABSTRACT The prevalence of Escherichia coli O157 associated with feedlot cattle in Saskatchewan was determined in a 10-month longitudinal study (3 feedlots) and a point prevalence study (20 feedlots). The prevalence of E. coli O157 at the three different sites in the horizontal study varied from 2.5 to 45%. The point prevalence of E. coli O157 among Saskatchewan cattle from 20 different feedlots ranged from 0% to a high of 57%. A statistically significant (P = 0.003) positive correlation was determined to exist between the density of cattle and the E. coli O157 prevalence rate. A significant correlation (P = 0.006) was also found between the E. coli O157 percent prevalence and the number of cattle housed/capacity ratio. All 194 E. coli O157 isolates obtained were highly virulent, and random amplified polymorphic DNA PCR analysis revealed that the isolates grouped into 39 different E. coli O157 subtypes, most of which were indigenous to specific feedlots. Two of the most predominant subtypes were detected in 11 different feedlots and formed distinct clusters in two geographic regions in the province. Antimicrobial susceptibility testing of the E. coli O157 isolates revealed that 10 were multidrug resistant and that 73 and 5 were resistant to sulfisoxazole and tetracycline, respectively.
18
Koyun, Osman Y., Igori Balta, Nicolae Corcionivoschi, and Todd R. Callaway. "Disease Occurrence in- and the Transferal of Zoonotic Agents by North American Feedlot Cattle." Foods 12, no. 4 (February 20, 2023): 904. http://dx.doi.org/10.3390/foods12040904.
Full textAbstract:
North America is a large producer of beef and contains approximately 12% of the world’s cattle inventory. Feedlots are an integral part of modern cattle production in North America, producing a high-quality, wholesome protein food for humans. Cattle, during their final stage, are fed readily digestible high-energy density rations in feedlots. Cattle in feedlots are susceptible to certain zoonotic diseases that impact cattle health, growth performance, and carcass characteristics, as well as human health. Diseases are often transferred amongst pen-mates, but they can also originate from the environment and be spread by vectors or fomites. Pathogen carriage in the gastrointestinal tract of cattle often leads to direct or indirect contamination of foods and the feedlot environment. This leads to the recirculation of these pathogens that have fecal–oral transmission within a feedlot cattle population for an extended time. Salmonella, Shiga toxin-producing Escherichia coli, and Campylobacter are commonly associated with animal-derived foods and can be transferred to humans through several routes such as contact with infected cattle and the consumption of contaminated meat. Brucellosis, anthrax, and leptospirosis, significant but neglected zoonotic diseases with debilitating impacts on human and animal health, are also discussed.
19
Fazzio, Luis E., Nicolas Yacachury, Walter R. Galvan, Elias Peruzzo, Ricardo O. Sánchez, and Eduardo J. Gimeno. "Impact of ivermectin-resistant gastrointestinal nematodes in feedlot cattle in Argentina." Pesquisa Veterinária Brasileira 32, no. 5 (May 2012): 419–23. http://dx.doi.org/10.1590/s0100-736x2012000500010.
Full textAbstract:
The aim was to evaluate for 75 days the impact on production of the remaining burden of ivermectin (IVM)-resistant parasites in naturally infected feedlot calves. The herds came from tick-infested areas of cattle breeding where the systematic use of IVM to control tick increases the gastrointestinal parasites resistant to this drug. This investigation was carried out in two commercial feedlots in Buenos Aires province. In feedlot A, two groups of 35 animal each received IVM 1% and the other received ricobendazole (RBZ) 10% respectively. The same was done in feedlot B. On day 0, two groups of 35 animals were made in feedlots A and B. Fecal samples were taken on days 0, 22, 54 and 75 pos-treatment (PT), and body weight was registered, from each animal. Fecal samples were processed for individual count of eggs per gram (EPG) and pooled fecal culture was carried out for identification of the parasite genus in each sampling. Fecal egg count reduction test (FECR) was calculated on day 22 PT. The study design used was a totally randomized block, with commercial feedlot and sex as block variables. For data analysis, a mixed model of the SAS statistical program was used. The FECR average on day 22 was 28.4% in the IVM group, and 94,2 % in the RBZ group . From this date on, significant differences in EPG were kept until day 54. EPG counts were only equal near the end of the trial, on day 75 (p=0.16). In both commercial feedlots, especially in the IVM group, Cooperia spp. was the most prevalent parasite in the fecal cultures. Significant differences in weight (P<0.01) on post-treatment day 75 was found between the average weight in the RBZ and the IVM group (246 vs. 238 kg respectively), what means a difference of 8.3% in gains. The importance for production in the antiparasite failure treatment in commercial feedlots was demonstrated, and the need of pos-treatment controls to evaluate the efficacy of the antiparasitic administered is emphasized.
20
Bai, Mei, David W. T. Griffith, Frances A. Phillips, Travis Naylor, Stephanie K. Muir, Sean M. McGinn, and Deli Chen. "Correlations of methane and carbon dioxide concentrations from feedlot cattle as a predictor of methane emissions." Animal Production Science 56, no. 1 (2016): 108. http://dx.doi.org/10.1071/an14550.
Full textAbstract:
Accurate measurements of methane (CH4) emissions from feedlot cattle are required for verifying greenhouse gas (GHG) accounting and mitigation strategies. We investigate a new method for estimating CH4 emissions by examining the correlation between CH4 and carbon dioxide (CO2) concentrations from two beef cattle feedlots in Australia representing southern temperate and northern subtropical locations. Concentrations of CH4 and CO2 were measured at the two feedlots during summer and winter, using open-path Fourier transform infrared spectroscopy. There was a strong correlation for the concentrations above background of CH4 and CO2 with concentration ratios of 0.008 to 0.044 ppm/ppm (R2 >0.90). The CH4/CO2 concentration ratio varied with animal diet and ambient temperature. The CH4/CO2 concentration ratio provides an alternative method to estimate CH4 emissions from feedlots when combined with CO2 production derived from metabolisable energy or heat production.
21
Goonewardene, L. A., and R. K. Hand. "Studies on dehorning steers in Alberta feedlots." Canadian Journal of Animal Science 71, no. 4 (December 1, 1991): 1241–47. http://dx.doi.org/10.4141/cjas91-147.
Full textAbstract:
The study contained 507 crossbred steers from seven lots in five owner-operated feedlots. The objective was to determine the effects of dehorning (DH) at the feedlot on growth rate, compared to a control (CO) consisting of polled or previously dehorned steers. Significant (P < 0.01) treatment differences (DH = 1.11 ± 0.01 kg d−1, CO = 1.16 ± 0.01 kg d−1) and treatment × lot interaction were observed for average daily gain from 0 to 106 d. Key words: Dehorning, steers, feedlot, gain
22
Grandin, Temple. "253 Make Yourself Really Good at Your Career." Journal of Animal Science 98, Supplement_3 (November 2, 2020): 147–48. http://dx.doi.org/10.1093/jas/skaa054.259.
Full textAbstract:
Abstract In the 1970’s when I started my career, there were no women working in the feedlots with the cattle. Being a woman at this time was a much bigger obstacle than my awkward social skills due to autism. I created my own internships at Arizona feedlots and the Swift Tolleson plant. I handled cattle along with the feedlot processing crews. There was a nice man who ran a contract processing crew who taught me how to move cattle. The worst treatment I received came from cowboy foremen who were the cattle managers for the entire feedlot. The feedlot owners and the more senior bosses were usually helpful. I made myself highly knowledgeable in the specialized area of the design of cattle handling facilities. At this time there were few people in this field. I learned to sell my work by showing people my detailed drawings and photos of completed projects. Another skill I had was writing, and it really helped my career. After I completed a project, I wrote about it in both local and national livestock publications.
23
FEDORKA-CRAY, P. J., D. A. DARGATZ, L. A. THOMAS, and J. T. GRAY. "Survey of Salmonella Serotypes in Feedlot Cattle§." Journal of Food Protection 61, no. 5 (May 1, 1998): 525–30. http://dx.doi.org/10.4315/0362-028x-61.5.525.
Full textAbstract:
A national study of health and management of cattle in feedlots was conducted. Within this study, the prevalence of Salmonella spp. in fecal samples was determined. Fifty fecal samples were collected from each of 100 feedlots. Within each feedlot, 25 fresh fecal samples were collected from the floor of the pens of cattle which had been on feed the shortest and 25 from those on feed the longest periods of time. The total number of samples collected was 4,977; 2,484 and 2,495 from pens of cattle on feed the shortest and longest times, respectively. Salmonella spp. were recovered from 38% (38 of 100) of the feedlots. Salmonella spp. were recovered from 5.5% (273 of 4,977) of all samples and from 3.5% (88 of 2,484) and 7.4% (185 of 2,495) of samples from pens of cattle shortest and longest on feed, respectively. The most common serotype recovered was S. anatum (27.9%), followed by S. montevideo (12.9%), S. muenster (11.8%), S. kentucky (8.2%), and S. newington (4.3%). The most common serogroups identified were El (39.6%), C1 (20.7%), and B (10.4%). Shedding of the serotypes most commonly associated with human illness occurred infrequently (13 of 273: 4.8%). This study provides information on the status of Salmonella spp. from cattle in feedlots and may serve as baseline information for future studies.
24
Gilreath, Jessica, Al Rotz, Sara Place, Greg Thoma, and Tryon Wickersham. "520 Late-Breaking: Effect of Technology on Environmental Emissions from Four Representative U.S. Feedlots and the Beef Production System." Journal of Animal Science 99, Supplement_3 (October 8, 2021): 155. http://dx.doi.org/10.1093/jas/skab235.285.
Full textAbstract:
Abstract Our objective was to evaluate effects of technological management strategies on environmental impacts and net returns of feedlot operations in the United States. Feedlot operations were simulated with the Integrated Farm System Model (IFSM 4.6; USDA-ARS, University Park, PA) to quantify baseline environmental impacts of feedlot production and full US beef cattle production systems. Strategies simulated included: ionophore, implant, ractopamine hydrochloride, combined management (ionophore, implant, and ractopamine hydrochloride; I+I+R), lubabegron, reduced mortality rate, and improved fiber digestion. Days on feed were adjusted whenever necessary and according to production practices typical of commercial feedlots. Subsequently, annual number of cattle finished by the operation was adjusted according to days on feed to maintain consistent one-time capacities. Mitigation strategies were individually modeled and simulated in IFSM for each feedlot operation to calculate intensities (expressed per kg gain) for greenhouse gas (GHG) emissions, fossil energy use, blue water consumption, and reactive nitrogen loss. Additionally, net returns to management were estimated for each feedlot operation. Feedlots were then integrated with simulations of cow-calf, stocker, and backgrounding operations to estimate environmental intensities (expressed per kg carcass weight) for the full beef cattle production system. Carbon emission intensity was reduced most using the I+I+R strategy (10%), followed by implant (6%) and ionophore (5%) strategies alone. Similarly, energy use intensity was reduced the greatest by I+I+R (9%), ionophore (5%), and implants (4%). Reductions in water use intensity were also greatest using I+I+R (9%). Net returns increased for all strategies compared to baseline net return with the greatest improvements observed for I+I+R ($114/finished animal) and implants ($66/animal). Consistent results were observed for all strategies simulated across all four environmental intensities when quantified for the full cattle production system. Implementing I+I+R (7%), ractopamine hydrochloride (4%), and lubabegron (4%) in feedlots resulted in the greatest reductions in environmental emissions.
25
Lee, Catrione, Rahat Zaheer, Krysty Munns, Devin B. Holman, Gary Van Domselaar, Athanasios Zovoilis, and Tim A. McAllister. "Effect of Antimicrobial Use in Conventional Versus Natural Cattle Feedlots on the Microbiome and Resistome." Microorganisms 11, no. 12 (December 14, 2023): 2982. http://dx.doi.org/10.3390/microorganisms11122982.
Full textAbstract:
Antimicrobial use (AMU) in the livestock industry has been associated with increased levels of antimicrobial resistance. Recently, there has been an increase in the number of “natural” feedlots in the beef cattle sector that raise cattle without antibiotics. Shotgun metagenomics was employed to characterize the impact of AMU in feedlot cattle on the microbiome, resistome, and mobilome. Sequenced fecal samples identified a decline (q < 0.01) in the genera Methanobrevibacter and Treponema in the microbiome of naturally vs. conventionally raised feedlot cattle, but this difference was not (q > 0.05) observed in catch basin samples. No differences (q > 0.05) were found in the class-level resistome between feedlot practices. In fecal samples, decreases from conventional to natural (q < 0.05) were noted in reads for the antimicrobial-resistant genes (ARGs) mefA, tet40, tetO, tetQ, and tetW. Plasmid-associated ARGs were more common in feces from conventional than natural feedlot cattle. Interestingly, more chromosomal- than plasmid-associated macrolide resistance genes were observed in both natural and conventional feedlots, suggesting that they were more stably conserved than the predominately plasmid-associated tetracycline resistance genes. This study suggests that generationally selected resistomes through decades of AMU persist even after AMU ceases in natural production systems.
26
Hilton, W. Mark. "BRD in 2014: where have we been, where are we now, and where do we want to go?" Animal Health Research Reviews 15, no. 2 (October 31, 2014): 120–22. http://dx.doi.org/10.1017/s1466252314000115.
Full textAbstract:
AbstractBovine respiratory disease (BRD) is a worldwide health concern and is the number one disease of stocker, backgrounder, and feedlot cattle in North America. In feedlots in the USA, BRD accounts for 70–80% of all feedlot morbidity and 40–50% of all mortality. In 2011, the US Department of Agriculture's National Animal Health Monitoring System conducted a feedlot study that showed 16.2% of all feedlot cattle were treated for BRD. It is universally accepted that this number is distressingly high and that our industry has the tools available to reduce the incidence of BRD.
27
Denmead, O. T., D. Chen, D. W. T. Griffith, Z. M. Loh, M. Bai, and T. Naylor. "Emissions of the indirect greenhouse gases NH3 and NOx from Australian beef cattle feedlots." Australian Journal of Experimental Agriculture 48, no. 2 (2008): 213. http://dx.doi.org/10.1071/ea07276.
Full textAbstract:
Emissions of indirect greenhouse gases, notably the nitrogen gases ammonia (NH3) and the odd oxides of nitrogen (NOx), play important roles in the greenhouse story. Feedlots are intense, but poorly quantified, sources of atmospheric NH3 and although production of NOx is to be expected in feedlots, rates of NOx emission are virtually unknown. In the atmosphere, these gases are involved in several transformations, but eventually return to the earth in gaseous or liquid form and can then undergo further transformations involving the formation and emission of the direct greenhouse gas nitrous oxide (N2O). The IPCC Phase II guidelines estimate that indirect N2O emissions due to atmospheric deposition of N compounds formed from NH3 and NOx could be ~14% of the direct emissions from agricultural soils or from animal production systems. IPCC recommends that these indirect emissions be accounted for in making inventory estimates of N2O emission. This paper is a preliminary report of emissions of NH3 and NOx from two Australian feedlots determined with micrometeorological techniques. Emissions of nitrogen gases from both feedlots were dominated by emissions of NH3. The average NH3 emission rate over both feedlots in winter was 46 g N/animal.day, while that of NOx was less than 1% of that rate at 0.36 g N/animal.day. It was apparent that NH3 release was governed by the wetness of the surface. Rates of emission from the feedlot with the wetter surface were almost three times those from the other. The IPCC default emission factor for the combined emission of NH3 and NOx from livestock is 0.2 kg N/kg N excreted, but in our work, the emission factor was 0.59 kg N/kg N excreted. Potential emissions of N2O due to NH3 and NOx deposition were estimated to be of the same magnitude as the direct N2O emissions, the sum of direct and potential indirect amounting to ~3 g N2O-N/animal.day. If applied nationally, this would represent a contribution of N2O from Australian feedlots of 533Gg CO2-e or 2.2% of all Australian N2O emissions.
28
Eigenberg, Roger A., Bryan L. Woodbury, Brent W. Auvermann, David B. Parker, and Mindy J. Spiehs. "Energy and Nutrient Recovery from Cattle Feedlots." ISRN Renewable Energy 2012 (January 12, 2012): 1–5. http://dx.doi.org/10.5402/2012/723829.
Full textAbstract:
Selective harvesting of manure can benefit cattle producers by creating a product of value. A tool that identifies locations of manure accumulation has been developed using a subsurface sensor (Dualem-1S, Milton, ON) and software designed for salt mapping (ESAP, Riverside, CA). The combination allowed the development of models to estimate higher heating value (HHV) of feedlot manure across a feedlot pen. Soil sample data from cattle feedlots in Texas and Nebraska were analyzed for volatile solids (VSs) then combined with the Dualem-1S apparent soil conductivity () data to produce models having correlations between associated values and VS (, VS). A corresponding model is under development to estimate the moisture content of the collectable solids. The combined models allow real-time spatial estimates of HHV within a feedlot pen. These methods will allow direct harvesting of VS for use as a recoverable energy source through direct combustion or cocombustion.
29
FREEZE, B. S., and T. G. SOMMERFELDT. "BREAKEVEN HAULING DISTANCES FOR BEEF FEEDLOT MANURE IN SOUTHERN ALBERTA." Canadian Journal of Soil Science 65, no. 4 (November 1, 1985): 687–93. http://dx.doi.org/10.4141/cjss85-074.
Full textAbstract:
The economics of hauling manure as a substitute for commercial fertilizer in the production of cultivated crops was investigated using a computer model that accommodates variables such as hauling distance, machinery complement, hauling speed, labor use, spreading time, and crop response. Machinery complement and labor requirements were defined and budgeted for three farm-feedlot scenarios, namely: a very large farm-feedlot (> 1000 head capacity), a large farm-feedlot (500–1000 head capacity), and a small farm-feedlot (< 500 head capacity). Results indicate that manure, valued for its N and P2O5 nutrient content, is generally an economical substitute for commercial fertilizer when hauled up to 15 km from feedlot sources. Large farm-feedlots, hauling manure less frequently and employing a farm tractor with front-end loader and single axle truck with a manure box, can haul manure up to 15 km and recover all costs. Small farm-feedlots employing a farm tractor with front-end loader and pull-type manure spreader can economically haul manure up to 15 km if non-cash costs and labor charges are disregarded. Alternatively, custom corral cleaners can be hired to haul manure up to 18 km in competition with commercial fertilizer on an N and P2O5 nutrient value basis. The yield benefits of manure increased the breakeven hauling distances dramatically for some crops. A need for more research to determine economic optimum manure application rates for various crops is identified. Key words: Fertilizer, feedlot manure, fertilizer economics, animal wastes
30
Erickson, Sarah E., Murray Jelinski, Karen S. Schwartzkopf-Genswein, Calvin Booker, and Eugene Janzen. "144 The Epidemiology of Hoof-related Lameness in Western Canadian Feedlot Cattle." Journal of Animal Science 99, Supplement_3 (October 8, 2021): 81–82. http://dx.doi.org/10.1093/jas/skab235.147.
Full textAbstract:
Abstract The epidemiology of hoof-related lameness (HRL) in western Canadian feedlots, with a focus on digital dermatitis (DD), was described and analyzed to help inform recommendations on lameness control and prevention in western Canadian feedlot cattle. The retrospective data in this study were accessed from 28 western Canadian feedlots that placed cattle in 2014–2018, inclusive. The total population for this study was 1,796,176 cattle, with an annual placement average of 12,830 cattle per feedlot. These data were accessed through iFHMS Consolidated Database, provided by Feedlot Health Management Services by TELUS Agriculture, and manipulated using Microsoft® Office Access 365 ProPlus and Microsoft® Office Excel 365 ProPlus. Epidemiological analyses determined that lameness accounts for 25.7% of all treatments in western Canadian feedlots. Of those treatments, 71.7% are localized to the hoof, corresponding to 18.6% of all treatments. The most common HRL diseases are infectious bovine pododermatitis [foot rot (FR)]; digital dermatitis (DD), also known as hairy-heel wart or strawberry foot rot; and toe-tip necrosis syndrome (TTNS). These diseases account for 89.6%, 7.9% and 2.4% of HRL, respectively. Between 2014 and 2018, HRL prevalence ranged between 1.93% and 3.09% of the population, with FR consistently having the highest prevalence and TTNS the lowest. HRL and DD were tested for their associations with several animal-level risk factors using © Ausvet 2021 Epitools software. The resultant crude, univariate odds ratio values, evaluated at 95% confidence, are summarized in Table 1. Based on this analysis, acquisition source has the largest influence on the odds of developing HRL and DD, followed by population size, and placement quarter. Using SAS® (Version 9.4, SAS Institute Inc, Cary, North Carolina) statistical software, these preliminary findings will be subjected to a multivariate statistical model, which will provide adjusted OR values and statistical significance for the data in this study.
31
HANCOCK, DALE D., DANIEL H. RICE, LEE ANN THOMAS, DAVID A. DARGATZ, and THOMAS E. BESSER. "Epidemiology of Escherichia coli O157 in Feedlot Cattle." Journal of Food Protection 60, no. 5 (May 1, 1997): 462–65. http://dx.doi.org/10.4315/0362-028x-60.5.462.
Full textAbstract:
Fecal samples from cattle in 100 feedlots in 13 states were bacteriologically cultured for Escherichia coli O157 that did not ferment sorbitol, lacked beta-glucuronidase, and possessed genes coding for Shiga-like toxin. In each feedlot 30 fresh fecal-pat samples were collected from each of four pens: with the cattle shortest on feed, with cattle longest on feed, and with cattle in two randomly selected pens. E. coli O157 was isolated from 210 (1.8%) of 11,881 fecal samples. One or more samples were positive for E. coli O157 in 63 of the 100 feedlots tested. E. coli O157 was found at roughly equal prevalence in all the geographical regions sampled. The prevalence of E. coli O157 in the pens with cattle shortest on feed was approximately threefold higher than for randomly selected and longest on feed pens. Of the E. coli O157 isolates found in this study, 89.52% expressed the H7 flagellar antigen. E. coli O157 was found to be widely distributed among feedlot cattle, but at a low prevalence, in the United States.
32
Aguilar, Orlando A., Ronaldo Maghirang, Charles W. Rice, Steven L. Trabue, and Larry E. Erickson. "Nitrous Oxide Fluxes from a Commercial Beef Cattle Feedlot in Kansas." Air, Soil and Water Research 7 (January 2014): ASWR.S12841. http://dx.doi.org/10.4137/aswr.s12841.
Full textAbstract:
Emission of greenhouse gases, including nitrous oxide (N2O), from open beef cattle feedlots is becoming an environmental concern; however, research measuring emission rates of N2O from open beef cattle feedlots has been limited. This study was conducted to quantify N2O emission fluxes as affected by pen surface conditions, in a commercial beef cattle feedlot in the state of Kansas, USA, from July 2010 through September 2011. The measurement period represented typical feedlot conditions, with air temperatures ranging from -24 to 39°C. Static flux chambers were used to collect gas samples from pen surfaces at 0, 15, and 30 minutes. Gas samples were analyzed with a gas chromatograph and from the measured concentrations, fluxes were calculated. Median emission flux from the moist/muddy surface condition was 2.03 mg m−2 hour−1, which was about 20 times larger than the N2O fluxes from the other pen surface conditions. In addition, N2O peaks from the moist/muddy pen surface condition were six times larger than emission peaks previously reported for agricultural soils.
33
Erickson, Sarah, Calvin Booker, Jiming Song, Eugene Janzen, Murray Jelinski, and Karen Schwartzkopf-Genswein. "Epidemiology of Digital Dermatitis in Western Canadian Feedlot Cattle." Animals 14, no. 7 (March 29, 2024): 1040. http://dx.doi.org/10.3390/ani14071040.
Full textAbstract:
Digital dermatitis (DD) is an emerging disease in feedlot cattle. Our objective was to identify animal- and feedlot-level risk factors for DD by analyzing individual animal health records (n = 1,209,883) and feedlot-level records from western Canadian feedlots (n = 28) between 2014 and 2018, inclusive. The risk of a DD diagnosis was higher (incidence rate ratio (IRR) = 2.08, 95% CI 1.52 to 2.86) in cattle sourced from confined background operations (CB) versus cattle sourced from auction markets (AM). Conversely, ranch direct (RD) cattle were (IRR = 0.02, 95% CI 0.04 to 0.30) lower risk than AM cattle of being diagnosed with DD. The risk of being diagnosed with DD was higher in females than in males. The magnitude of the risk in females over males was influenced by annual DD incidence in low morbidity years (2014, 2017, and 2018) (IRR = 2.02, 95% CI 1.27 to 3.19), medium morbidity years (2016) (IRR = 2.95, 95% CI 1.64 to 5.33), and high morbidity years (2015) (IRR = 5.41, 95% CI 3.27 to 8.95). At the feedlot-level, the risk of a diagnosis of DD was lower in small capacity (SCF) versus large capacity feedlots (LCF) (IRR = 0.24, 95% CI 0.05 to 0.76). Future research should focus on identifying factors that may propagate disease transmission between cattle of different sexes and from different acquisition sources.
34
Borshch, O. O., S. Yu Ruban, and B. V. Gutyj. "Comfort and cow behavior during periods of intense precipitation." Ukrainian Journal of Ecology 10, no. 6 (December 28, 2020): 98–102. http://dx.doi.org/10.15421/2020_265.
Full textAbstract:
The purpose of this work was to study the influence of prolonged precipitation as rain on the behavior and comfortable resting place of cows by housing on open feedlots with and without shelters. It was found that the duration of lying down was longer by 47 minutes for the variant of housing on open feedlots with shelters and eating feed by 8 minutes in compared to open feedlots without shelters. Concerning to the indicators of standing and motion behaviour, the duration of these behavioural act by the variant of housing on open feedlots without shelters was slightly longer compared to housing on open feedlots with shelters: by 29 and 18 minutes, respectively. The skin temperature of cows was 0.4 °C higher by housing on open feedlots without shelters than that cow by housing on open feedlots with shelters. The temperature of resting place under lying cow was also higher by housing on open feedlots without shelters (by 0.6 °C). At the same time, the temperature in recreation areas under the shelters prevailed by 0.2 °C, the same indicator by housing on open feedlots without shelters. The average values of daily energy consumption for basic metabolism and heat exchange were 1.50 MJ higher by housing on open feedlots without shelters. The best scores on the indices of hygienic assessment and comfort housing conditions were by the variant of housing on open feedlots with shelters. The cows were slightly less polluted on their flanks, udders and limbs by housing of this technology than by housing on open feedlots without shelters.
35
Larney, Francis J., Andrew F. Olson, Paul R. DeMaere, Brian P. Handerek, and Bonnie C. Tovell. "Nutrient and trace element changes during manure composting at four southern Alberta feedlots." Canadian Journal of Soil Science 88, no. 1 (February 1, 2008): 45–59. http://dx.doi.org/10.4141/cjss07044.
Full textAbstract:
Interest in composting as a means of handling the large volumes of manure generated by southern Alberta beef cattle feedlots has increased in recent years. We measured concentrations of 19 elements (C, N, P, Na, Ca, Mg, K, S, Al, Fe, Mn, Zn, Cu, Cr, Ni, P b , Co, Mo and Cd) in fresh manure, interim-composted manure and finished compost, at four commercial feedlots. Thirteen elements showed increased concentrations (by 26–73%) with composting, while four (C, Cr, Ni and Mo) showed concentration declines. Of the remaining two, the trend in N concentration was feedlot dependent, while Pb was largely unaffected. Total mass loss during composting averaged 54%, which represents a substantial decrease in haulage requirements. Overall average C losses were 61% and N losses 33%. On an equivalent wet weight basis ("as-is"), composting allowed haulage of 56% more N, 84% more P, 91% more Zn, and 76% more Cu than fresh manure, which is advantageous in terms of moving nutrients and trace elements from high to low-loading areas. Our study quantifies nutrient and trace element behaviour during composting, provides comparative data with fresh manure, and helps tailor end-use decisions (e.g., haulage distance, application rate) on the compost product. Key words: Manure, compost, beef cattle feedlots, nutrients, trace elements
36
Basarab, J. A., D. Milligan, and B. E. Thorlakson. "Traceback success rate of an electronic feedlot to slaughter information system for beef cattle." Canadian Journal of Animal Science 77, no. 3 (September 1, 1997): 525–28. http://dx.doi.org/10.4141/a97-047.
Full textAbstract:
The traceback success rate of an electronic feedlot to slaughter information system was evaluated using 4186 yearling cattle from three Alberta feedlots. Each animal was identified with an external Allflex electronic identification (EID) eartag before the end of the feeding period. The EID number was scanned with stationary Allflex TIRIS readers at the abattoir and electronically linked to its carcass data. The traceback success rate was 39.8% from abattoir to feedlot and 46.4% from abattoir to herd of origin. Key words: Allflex, electronic identification, reliability, transponder, cattle
37
XIE, YICHENG, JEFFREY W. SAVELL, ASHLEY N. ARNOLD, KERRI B. GEHRING, JASON J. GILL, and T. MATTHEW TAYLOR. "Prevalence and Characterization of Salmonella enterica and Salmonella Bacteriophages Recovered from Beef Cattle Feedlots in South Texas." Journal of Food Protection 79, no. 8 (August 1, 2016): 1332–40. http://dx.doi.org/10.4315/0362-028x.jfp-15-526.
Full textAbstract:
ABSTRACT Asymptomatic Salmonella carriage in beef cattle is a food safety concern, and the beef feedlot environment may function as a reservoir of this pathogen. The goal of this study was to identify and isolate Salmonella and Salmonella bacteriophages from beef cattle feedlot environments in order to better understand the microbial ecology of Salmonella and identify phages that might be useful as anti-Salmonella beef safety interventions. Three feedlots in south Texas were visited, and 27 distinct samples from each source were collected from dropped feces, feed from feed bunks, drinking water from troughs, and soil in cattle pens (n = 108 samples). Preenrichment, selective enrichment, and selective/differential isolation of Salmonella were performed on each sample. A representative subset of presumptive Salmonella isolates was prepared for biochemical identification and serotyping. Samples were pooled by feedlot and sample type to create 36 samples and enriched to recover phages. Recovered phages were tested for host range against two panels of Salmonella hosts. Salmonella bacteria were identified in 20 (18.5%) of 108 samples by biochemical and/or serological testing. The serovars recovered included Salmonella enterica serovars Anatum, Muenchen, Altona, Kralingen, Kentucky, and Montevideo; Salmonella Anatum was the most frequently recovered serotype. Phage-positive samples were distributed evenly over the three feedlots, suggesting that phage prevalence is not strongly correlated with the presence of culturable Salmonella. Phages were found more frequently in soil and feces than in feed and water samples. The recovery of bacteriophages in the Salmonella-free feedlot suggests that phages might play a role in suppressing the Salmonella population in a feedlot environment.
38
Mancke, M., B. White, E. Bortoluzzi, B. Depenbusch, P. Schmidt, P. Lancaster, and R. Larson. "Frequency of concurrent lesions in feedlot mortalities at necropsy." American Association of Bovine Practitioners Conference Proceedings, no. 56 (May 10, 2024): 231. http://dx.doi.org/10.21423/aabppro20238943.
Full textAbstract:
Feedlot mortalities continue to be a major economic issue for cattle producers. Necropsies have been utilized to help diagnose disease processes in commercial feedlots. However, identification of concurrent diagnoses and multiple-affected organ systems have been rarely recorded. The study objective was to determine the frequency and most common combinations of concurrent lesions and multiple-affected organ systems in feedlot mortalities.
39
de Andrade, Thiago Sérgio, Tiago Zanett Albertini, Luís Gustavo Barioni, Sérgio Raposo de Medeiros, Danilo Domingues Millen, Antônio Carlos Ramos dos Santos, Rodrigo Silva Goulart, and Dante Pazzanese Duarte Lanna. "Perception of consultants, feedlot owners, and packers regarding the optimal economic slaughter endpoint in feedlots: a national survey in Brazil (Part I)." Canadian Journal of Animal Science 100, no. 4 (December 1, 2020): 745–58. http://dx.doi.org/10.1139/cjas-2019-0219.
Full textAbstract:
Little information exists regarding the optimal economic slaughter endpoint (OSE) for feedlot-finished cattle in Brazil. This study investigated the perceptions of Brazilian feeders regarding the optimal time for slaughter. A total of 52 interviews were conducted involving nutritionist-consultants (n = 23), feedlot owners (n = 21), and packer-owned feedlots (n = 8). The results showed that 65% of the interviewees used weight and fat cover, both estimated visually, to determine the moment for slaughter. Identifying the ideal time for slaughter was considered a challenge for respondents, and 85% of them recognized that their current slaughter endpoint identification method needed improvements. Regarding decision support systems, 58% of respondents reported they would purchase a computer program to help identify OSE, and 73% would be interested in incorporating a prototype of such a system into their feedlots. Carcass dressing (38%) and price (25%) were the main factors driving the feeder’s choice of meatpacker, followed by carcass premiums (10%). Meat quality was found to be an irrelevant criterion for Brazilian meatpackers in awarding both premiums (5%) and deductions (3%). Slaughter endpoint is determined subjectively by the Brazilian feeders, based on a visual evaluation of both weight and fatness.
40
Storz, J., L. Stine, A. Liem, and G. A. Anderson. "Coronavirus isolation from nasal swab samples in cattle with signs of respiratory tract disease after shipping." Journal of the American Veterinary Medical Association 208, no. 9 (May 1, 1996): 1452–55. http://dx.doi.org/10.2460/javma.1996.208.09.1452.
Full textAbstract:
Objective To monitor the prevailing viral respiratory tract infections in cattle after transportation to feedlots. Animals 100 cattle with signs of respiratory tract disease on arrival at 2 feedlots. Procedures Nasal swab samples were obtained from each animal and were used for inoculation of defined cell culture systems that detected bovine viruses known to cause respiratory tract infections, as well as viruses previously not recognized as respiratory pathogens for cattle. Results Bovine respiratory coronaviruses were isolated from 38 of the 100 cattle, including 6 of 50 cattle from California, 22 of 31 cattle from Oklahoma, 6 of 11 cattle from Texas, and 4 of 8 cattle of unknown origin. Parainfluenza 3 viruses also were isolated from 4 California cattle, but other bovine viruses were not detected. Clinical Implications The high rate of coronavirus isolations from feedlot cattle with signs of respiratory tract disease implied wide distribution and high susceptibility among cattle to this infection, which had not been detected by use of viral isolation systems in previous etiologic evaluations of feedlot cattle affected with bovine respiratory disease complex. (J Am Vet Med Assoc 1996; 208:1452-1455)
41
Schatz, T. J. "A comparison of the growth of Brahman and F1 Senepol × Brahman steers in an Indonesian feedlot." Animal Production Science 57, no. 10 (2017): 2096. http://dx.doi.org/10.1071/an16211.
Full textAbstract:
This study compares the performance of F1 Senepol × Brahman steers (F1 SEN) to Brahman (BRAH) steers in an Indonesian feedlot. The focus was to address concerns that crossbred cattle are discriminated against by live export cattle buyers due to a perception that they do not perform as well as Brahmans in Indonesian feedlots. F1 SEN (n = 54) and BRAH (n = 32) steers that had grazed together since weaning at Douglas Daly Research Farm (Northern Territory) were exported to Indonesia and fed for 121 days in a feedlot near Lampung (Sumatra, Indonesia). The average daily gain of the F1 SEN steers over the feeding period was 0.17 kg/day higher (P < 0.001) than the BRAH steers (1.71 vs 1.54 kg/day). As a result the F1 SEN put on an average of 21.6 kg more over the 121-day feeding period and they did not have a higher mortality rate. Consequently, F1 SEN steers performed better than BRAH in an Indonesian feedlot and these results should encourage live export cattle buyers to purchase this type of cattle (Brahman crossed with a tropically adapted Bos taurus breed) with confidence that they can perform at least as well as Brahmans in Indonesian feedlots, although it should be noted that growth rates are usually higher in F1 crosses than in subsequent generations.
42
Fernandes, Arthur Francisco Araujo, Joao R. Dorea, Thais B. Amaral, and Guilherme J. M. Rosa. "169 Investigating relationships between weather variables and dry matter intake of beef cattle in feedlot." Journal of Animal Science 98, Supplement_4 (November 3, 2020): 124–25. http://dx.doi.org/10.1093/jas/skaa278.227.
Full textAbstract:
Abstract Currently, the amount of feed delivered daily in feedlots is based on the previous day’s consumption and the estimated animal growth. Nevertheless, factors such as weather variables may influence feed consumption. The objective of this study was to evaluate the effect of weather on dry matter intake (DMI) in beef cattle finished in a commercial feedlot facility in South America. A total of 8.388 animals (Nellore and crossbreed Nellore x Angus) divided across 55 pens were evaluated from July 2018 to April 2019. The animals entered the feedlots with average body weight (BW) of 337 ± 28 kg and had a harvest BW of 517 ± 33 kg, with an average of 125 ± 25 days in feedlot. Daily feed consumption in each pen was estimated by subtracting any morning leftover feed from the total feed amount delivered on the previous day. Data on 16 weather variables for the farm location (latitude and longitude) was acquired using the Dark Sky API and processed in R. The weather variables were clustered via hierarchical cluster into groups given by: G1) humidity, cloud cover, and precipitation; G2) dew point, temperature (max, min, apparent max and apparent min), and day length; G3) atmospheric ozone and pressure; G4) UV index and visibility; G5) wind speed and gust; and G6) moon phase. Variables in G3 were positively correlated with DMI, while G2 and G4 presented negative correlations. The most important correlations were for day length (r = -0.74, P < 0.01), apparent max temperature (r = -0.65, P < 0.05), dew point (r = -0.65, P < 0.05), ozone (r = 0.62,P < 0.05), and pressure (r = 0.61, P < 0.05). In conclusion, several weather variables presented potential as candidate for the development of predictive models of DMI of beef cattle in feedlots.
43
Lawrence, John D., Zhi Wang, and Dan Loy. "Elements of Cattle Feeding Profitability in Midwest Feedlots." Journal of Agricultural and Applied Economics 31, no. 2 (August 1999): 349–57. http://dx.doi.org/10.1017/s1074070800008622.
Full textAbstract:
AbstractConventional wisdom and earlier research have concluded that cattle feeding profitability is more determined by feeder and fed cattle prices than by animal performance. This study examined cross-sectional and time-series data from over 1600 pens of cattle in more than 220 feedlots in the upper Midwest where weather and lot conditions are thought to influence feedlot profitability. In addition to input and output prices and animal performance, other factors found to significantly impact cattle feeding profitability were sex, placement weight, facility design, and to a lesser extent placement season.
44
Wang, Erda, and Ed Sparling. "Economics of widespread manure application to irrigated crops: Raw and composted feedlot manure in eastern Colorado." American Journal of Alternative Agriculture 10, no. 4 (December 1995): 167–72. http://dx.doi.org/10.1017/s0889189300006421.
Full textAbstract:
AbstractWe used linear programming to simulate adoption of manure disposal technologies in eastern Colorado. Manure, either raw or composted, is assumed to be applied to irrigated cropland within 20 miles of feedlots in five subregions of eastern Colorado. We constrained the application so that total N application is no more than the amount used by the crop. N, P and K contents are taken into account, but no benefits are assigned to organic matter or trace minerals and no costs are assigned to soil compaction, weed seed propagation, or inconvenience. Irrigated land within 10 miles of feedlots can easily absorb all manure generated under this scenario. Manure is found to be an economical substitute for chemical fertilizers, assuming N content to be at least 50% that of fresh manure. Composted manure is either more or less profitable than raw manure, depending on its N content. Hauling costs are lower for compost, but composting costs are between $1 and $2 per finished ton. The model does not allow for mixed application of compost and chemical fertilizers, which would increase the value of compost significantly. A feedlot waste sector that composted all feedlot manure in eastern Colorado is predicted to create between 80 and 200 additional jobs.
45
Quimby, W. F., B. F. Sowell, J. G. P. Bowman, M. E. Branine, M. E. Hubbert, and H. W. Sherwood. "Application of feeding behaviour to predict morbidity of newly received calves in a commercial feedlot." Canadian Journal of Animal Science 81, no. 3 (September 1, 2001): 315–20. http://dx.doi.org/10.4141/a00-098.
Full textAbstract:
The objective of this study was to use feeding behavior of newly received steers (average initial weight 191 kg) to detect morbidity in animals in a commercial feedlot. Two separate 32 d feeding trials were conducted in Wellton, Arizona, in July and November 1996. Radio frequency technology was used to record the total time spent within 50 cm of the feedbunk (animal presence every 5.25 s times 5.25 s) in 3 h intervals from 0600 to 2400 on a daily basis for 103 and 122 male calves in trial 1 and 2, respectively. Statistical procedures based on the cumulative sums (CUSUM) of the 3 h feeding intervals were used to detect morbid animals, compared with detection of animals deemed morbid by experienced pen riders. In trial 1, the CUSUM procedure detected animal morbidity 4.5 d earlier (P < 0.001) than the feedlot personnel. In trial 2, the CUSUM procedure detected animal morbidity 3.7 d earlier (P < 0.001) than feedlot pen riders. Overall accuracy, positive predictive value and sensitivity of the CUSUM prediction method were 87, 91, and 90%, respectively. Combined trial data suggest that feeding behavior during the first 30 d cattle are in a receiving pen, as collected with radio frequency technology and analyzed with CUSUM charts, may be used to detect animal morbidity approximately 4.1 d earlier (P < 0.001) than conventional methods typically employed in commercial feedlots. Key words: Feeding behavior, morbidity, quality control, feedlots
46
Hunnicutt, Lynn, Dee Von Bailey, and Michelle Crook. "Rigidity in Packer-Feedlot Relationships." Journal of Agricultural and Applied Economics 36, no. 3 (December 2004): 627–38. http://dx.doi.org/10.1017/s1074070800026912.
Full textAbstract:
Concentration in beef packing has risen dramatically in the past 25 years. We develop measures used to describe feedlot-packer relations: (1) a statistic based on the proportion of its sales a feedlot makes to a given packer, and (2) a measure of the switching behavior of feedlots. The measures are calculated using a confidential data set from the USDA Grain Inspection, Packers, and Stockyards Administration. Relationships are found to be both exclusive and stable. Causes for this rigidity are then examined using regression analysis. Transaction costs are shown to help explain why this market differs from a perfectly competitive one.
47
Sundman, E., S. Millman, S. Erickson, G. Silva, D. Thomson, A. Johnson, K. Schwartzkopf-Genswein, R. Dewell, and G. Dewell. "Are there opportunities to strengthen animal welfare through improved management of feedlot chronic pens?" American Association of Bovine Practitioners Conference Proceedings, no. 56 (May 10, 2024): 195. http://dx.doi.org/10.21423/aabppro20238907.
Full textAbstract:
In feedlot cattle production systems, there is a population of sick cattle that fail to respond to treatment, are deemed chronically ill, and typically placed in a “chronic pen”. This population of chronic cattle is understudied in the current literature, and the absence of evidence-based protocols and guidance resources may lead to specific cattle welfare risks associated with chronic pens. Anecdotally, management of this population of animals varies widely across feedlots with potential impacts on animal welfare and productivity. The purpose of this descriptive epidemiologic study was to identify and describe key demographic patterns in chronic feedlot cattle populations.
48
Grooms, Daniel L., and Lee Anne K. Kroll. "Indoor Confined Feedlots." Veterinary Clinics of North America: Food Animal Practice 31, no. 2 (July 2015): 295–304. http://dx.doi.org/10.1016/j.cvfa.2015.03.007.
Full text
49
Schake, Lowell M., K. S. Lusby, and F. H. Baker. "Performance of Cattle Fed in Commercial Feedlots and Feedlot Operating Expenses1." Professional Animal Scientist 6, no. 1 (June 1990): 26–32. http://dx.doi.org/10.15232/s1080-7446(15)32241-5.
Full text
50
Bumunang, Emmanuel W., Vinicius S. Castro, Trevor Alexander, Rahat Zaheer, Tim A. McAllister, Le Luo Guan, and Kim Stanford. "In Silico Analysis of Shiga Toxin-Producing Escherichia coli O157:H7 Strains from Presumptive Super- and Low-Shedder Cattle." Toxins 16, no. 2 (February 5, 2024): 86. http://dx.doi.org/10.3390/toxins16020086.
Full textAbstract:
Cattle are the primary reservoir for STEC O157, with some shedding >104 CFU/g in feces, a phenomenon known as super-shedding (SS). The mechanism(s) responsible for SS are not understood but have been attributed to the environment, host, and pathogen. This study aimed to compare genetic characteristics of STEC O157 strains from cattle in the same commercial feedlot pens with SS or low-shedding (LS) status. Strains from SS (n = 35) and LS (n = 28) collected from 11 pens in three feedlots were analyzed for virulence genes, Shiga toxin-carrying bacteriophage insertion sites, and phylogenetic relationships. In silico analysis showed limited variation regarding virulence gene profiles. Stx-encoding prophage insertion sites mrlA and wrbA for stx1a and stx2a, respectively, were all occupied, but two isolates had fragments of the stx-carrying phage in mrlA and wrbA loci without stx1a and stx2a. All strains screened for lineage-specific polymorphism assay (LSPA-6) were 111111, lineage I. Of the isolates, 61 and 2 were clades 1 and 8, respectively. Phylogenetic analysis revealed that pens with more than one SS had multiple distantly related clusters of SS and LS isolates. Although virulence genes and lineage were largely similar within and across feedlots, multiple genetic origins of strains within a single feedlot pen illustrate challenges for on-farm control of STEC.