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1
Edvantoro, Bagus Bina. "Bioavailability, toxicity and microbial volatilisation of arsenic in soils from cattle dip sites." Title page, Contents and Abstract only, 2000. http://web4.library.adelaide.edu.au/theses/09A/09ae24.pdf.
Повний текст джерела
2
Deresz, Fermino. "Effect of different cooling systems on concentrations of certain hormones and free fatty acids at varying times during lactation of Holstein cows." Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/184260.
Повний текст джерелаАнотація:
In experiment 1, fourteen cows were blocked for milk yields and balanced for days in lactation. Treatments were: (1) Air conditioning (AC), five cows; (2) Evaporative cooling (EC), four cows; and (3) Conventional shade (S), five cows. Sequential samples were taken for 8 h at 12 min intervals starting at 2200 and then at hourly intervals for 13 h. Serum was assayed for insulin, thyroxine (T4), triiodothyronine (T3) and cortisol using a double-antibody radioimmunoassay procedure. Free fatty acids (FFA) were determined in serum by an enzymatic method. In experiment 2, ten cows were blocked for milk yields and days in lactation. Treatments were: (1) Evaporative cooling (EC), five cows; and (2) conventional shade (S), five cows. Blood was drawn at 60 and 90 d of lactation. Blood sampling, hormone and FFA assays were carried out as in experiment 1. Sequential samples were taken for 8 h at 12 min intervals starting at 2300 and then at hourly intervals from 1030 to 1830. In experiment 1, insulin was depressed (P <.05) treatment effects for T3 in either experiment. There were significant treatment differences (P <.05) in respiration rates and body temperatures in experiment 1. Shade were higher than AC or EC cows. These studies demonstrated that summer heat stress depressed insulin and increased FFA with variable effects on T4 and cortisol but no effect on T3.
3
Higginbotham, Gerald Ernest. "Influence of protein level and degradability on performance of lactating cows during hot and cool environmental temperatures." Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/184265.
Повний текст джерелаАнотація:
One hundred and twenty lactating Holstein cows in mid-lactation were offered diets varying in protein level and degradability at two locations during hot and moderate weather. Treatments were: (1) High protein (19%), high degradability (65%); (2) High protein (19%), medium degradability (40%); (3) Medium protein (15.5%), high degradability (65%); (4) Medium protein (15.5%), medium degradability (40%). Diets were individually fed during hot weather at the University of Arizona Dairy Farm and contained 38.4% alfalfa hay, 12.4% cottonseed hulls, 9.8% whole cottonseed, and 39.4% concentrate (dry matter). Diets were group fed during moderate weather at the Brigham Young University Dairy Farm, Provo, Ut, and contained 31.3% corn silage, 14% alfalfa haylage, 9.4% whole cottonseed and 45.3% concentrate (dry matter). Average daily ambient temperatures were 35.1°C for hot and 26.8°C for moderate weather locations. Fat-corrected milk (3.5%, 2 x milkings) and milk persistency were lower for treatment 1 than other treatments. For the respective treatments during hot weather means were: 23.4, 26.6, 28.5, 28.4 kg/d; 83.2, 91.2, 90.9, 90.3%; and for moderate weather means were: (3 x milkings): 34.7, 31.8, 32.2, 32.4 kg/d; 97.0, 93.4, 92.1, 90.3%. Dry matter intakes during hot weather were 21.5, 21.9, 23.3, and 23.1 kg/d. Respiration rate and rectal temperature during hot weather were: 90.1, 87.9, 90.9, 94.7 counts/min; 39.0, 39.3, 39.3, 39.5°C and for moderate weather: 61.2, 58.2, 55.5, 67.4 counts/min; 38.8, 38.6, 38.7, 38.8°C. Serum T₃,T₄ and cortisol were generally unaffected by treatment, but were depressed during hot weather. Serum glucose was not significantly affected by treatments at either environmental locations. Animals consumed more water with highly degradable protein diets at each location along with consuming more water during thermal stress. These data show that 3.5% fat-corrected milk and milk persistency are significantly affected (P <.01; P <.025) by rations high in protein of high degradability during heat stress.
4
Jiao, You 1966. "Phosphorus sorption and release as influenced by fertilizer sources in conventional and no-tillage agroecosystems." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=100631.
Повний текст джерелаАнотація:
Eutrophication resulting from phosphorus (P) accumulation in water systems has been a worldwide concern for three decades. Agricultural soils are known to be an important non-point source of P in waterways. The objectives of this research are to identify agricultural management practices that reduce the risk of P loss from soils, and to investigate the underlying mechanisms of P retention and loss from soils. In the short term (4 years), dissolved P loads were not affected by tillage and were similar in corn (in a continuous corn rotation) and soybean (in a soybean/corn rotation) production systems. Soils amended with composted cattle manure had a greater P load than chemically fertilized soils. On average, 30% of the total P leached was in organic P forms, indicating that organic P compounds could also be problematic to water systems. Although manure application improved soil aggregation and thus may increase P retention by avoiding soil erosion, P loss through subsurface flow by leaching may be substantial. A simple soil test, either Mehlich-3 P or P saturation ratio can predict the P leaching potential, but water ponding on the surface of agricultural land could significantly affect the accuracy of the prediction.The P adsorption data was fit with the Langmuir 2-surface model, which predicted that up to 90% of the native adsorbed P was distributed on the high-energy surface. Native adsorbed P in manured soils was weakly retained, as the binding strength coefficient was 50 times less in manured than chemically fertilized soil. This findings was confirmed by measuring P desorption, which showed that P desorption rate was almost 3 times greater from manured soils than from chemically fertilized soils. Manuring alters soil particle surfaces by increasing negative charge. This is the direct reason for less P adsorption and greater P desorption by manured soils.
The Langmuir 2-surface model and the adapted non-ideal competitive adsorption (MICA) model were equally good at modeling P adsorption data. However, the NICA model is more robust and can predict phosphate adsorption with changing soil solution pH. The simultaneously modeling of P adsorption and hydroxyl adsorption with the NICA model makes it a promising tool for analyzing competitive adsorption among anions in soils.
5
Blackburn, Lynda G. "Quantification and estimation of nitrous oxide emissions from dairy manure applications in a western Quebec pea-forage and an eastern Ontario alfalfa-forage cropping system : by Lynda G. Blackburn." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=100771.
Повний текст джерелаАнотація:
Agricultural systems are known to emit nitrous oxide (N2O)---a potent greenhouse gas. The roving flux tower measuring system of Agriculture and Agri-Food Canada was used to make continuous measurements of N2O fluxes in an edible pea field in Western Quebec in 2003-04 and then in an alfalfa-timothy forage field in Eastern Ontario in 2004-05. The experiment was designed to capture, at the field scale, the expected large N2O emissions occurring as a result of fertilizer application for a year, in relation to both large precipitation events and spring thaw.Growing season N2O emissions averaged 0.5 to 5 mg N2 O-N m-2 d-1 with peaks following snow melt (between 5 and 8 mg N2O-N m-2 d-1) and manure applications (8 to 37 mg N2O-N m-2 d -1). Although generally small (<0.25 mg N2O-N m -2 d-1), emissions were detectable during the fall and winter, indicating the importance of including them in annual emission totals.
The measurements were used to verify the performance of the simulation model DNDC (DeNitrification-DeComposition) in estimating N2O emissions from legumes and in response to dairy manure application. Sensitivity tests were also carried out in which baseline input values were modified. Results suggest that the current model version (DNDC8.9) requires further modification prior to application for estimating greenhouse gas emissions in national accounting systems.
6
Borucki, Castro Sylvia Irene. "Altering electrolyte balance of diets for lactating dairy cows to reduce phosphorus excretion to the environment." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=78324.
Повний текст джерелаАнотація:
The study was designed to test the hypothesis that P excretion in manure of dairy cattle could be reduced by manipulating electrolyte balance of the diet. Feces was the main route of P excretion, but fecal P was not affected by dietary cation-anion (DCAB) (P > 0.05). Plasma concentration of P tended (P < 0.10) to be higher at lower DCAB levels, implying that DCAB may have influenced P homeostasis. The overall P balance was not affected by the different DCAB levels. The range of DCAB where both P excretion and animal performance could be optimised is very narrow (+250 to +350 mEq/kg DM), so using DCAB to control P excretion in dairy cattle requires caution. (Abstract shortened by UMI.)
7
Cantin, Jean. "The environmental risks linked to different manure application periods /." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99326.
Повний текст джерелаАнотація:
More intensive production of hogs and cattle in Quebec during the past decade has benefited local economies, but led to over-fertilization of agricultural soils and eutrophication of waterways. Provincial ministries responded to this issue by developing regulations to control manure applications. The objective of this thesis was to determine the environmental risk associated with applying farm manure in the late fall. Spreading manure in fall after harvesting corn was a common practice for many agricultural producers in Quebec, but this period is now viewed as very risky, having more negative environmental consequences than other manure application periods. This two-year study used common diagnostic tools to compare the fertilization efficiency of solid dairy farm manure (DFM) spread in early fall, late fall and spring on a heavy clay soil used for corn production. In the first year, when DFM was the only nutrient source, there was no difference in corn yield that could be attributed to the manure application period. In the second year, each DFM plot was split and six levels of inorganic fertilizer (from 55 to 240 kg N ha-1) were applied ("Strip Split Plot") after planting. Corn tissue analysis (chlorophyll content, leaf N content at silking, cornstalk NO3 concentration) indicated that more residual N was supplied from late fall manure application than other manure application periods. Monitoring of soil NO3-N concentrations indicated that most of the NO3-N migration through the soil profile occurred after the early fall manure application. Late fall manure application appears to be the most efficient at supplying N for corn production, without deleterious environmental impacts, when DFM is applied to a heavy clay soil.
8
Fouty, Suzanne Catherine. "Current and historic stream channel response to changes in cattle and elk grazing pressure and beaver activity." Thesis, view abstract or download file of text, 2003. http://wwwlib.umi.com/cr/uoregon/fullcit?p3080584.
Повний текст джерелаАнотація:
Thesis (Ph. D.)--University of Oregon, 2003.Typescript. Includes vita and abstract. Includes bibliographical references (leaves 634-646). Also available for download via the World Wide Web; free to University of Oregon users.
9
Franz, Simone, and University of Lethbridge Faculty of Arts and Science. "The effect of cattle grazing in riparian areas on winter biodiversity and ecology." Thesis, Lethbridge, Alta. : University of Lethbridge, Dept. of Biological Sciences, c2009, 2009. http://hdl.handle.net/10133/2516.
Повний текст джерелаАнотація:
Livestock grazing in riparian habitats alters the vegetation structure, which has a detrimental effect on wildlife. This study examined the effect of cattle grazing in riparian habitats on winter bird biodiversity, small mammal biodiversity, and microclimate. Study sites were ungrazed, moderately grazed, and heavily grazed riparian habitats along the Oldman River, Alberta during winter 2005 and 2006. Bird species richness, individual abundance, and diversity indices were higher in ungrazed habitats than in grazed habitats. Deer mouse population sizes were not different except during spring 2006, when populations were larger in ungrazed sites. Microclimate data were collected in riparian sites and upland sites in winter 2006. Temperatures were higher and wind speeds were slower in riparian sites than in upland sites. Wind speeds were faster in heavily grazed riparian sites than in lightly grazed sites. Faster winds in heavily grazed sites may account for the decreased winter biodiversity in these habitats.x, 118 leaves ; 29 cm
10
Gill, Nicholas Geography & Oceanography Australian Defence Force Academy UNSW. "Outback or at home? : environment, social change and pastoralism in Central Australia." Awarded by:University of New South Wales - Australian Defence Force Academy. School of Geography and Oceanography, 2000. http://handle.unsw.edu.au/1959.4/38728.
Повний текст джерелаАнотація:
This thesis examines the responses of non-indigenous pastoralists in Central Australian rangelands to two social movements that profoundly challenge their occupancy, use and management of land. Contemporary environmentalism and Aboriginal land rights have both challenged the status of pastoralists as valued primary producers and bearers of a worthy pioneer heritage. Instead, pastoralists have become associated with land degradation, biodiversity loss, and Aboriginal dispossession. Such pressure has intensified in the 1990s in the wake of the native Title debate, and various conservation campaigns in the arid and semi-arid rangelands. The pressure on pastoralists occur in the context of wider reassessment of the social and economic values or rangelands in which pastoralism is seen as having declined in value compared to ???post-production??? land uses. Reassessments of rangelands in turn are part of the global changes in the status of rural areas, and of the growing flexibility in the very meaning of ???rural???. Through ethnographic fieldwork among largely non-indigenous pastoralists in Central Australia, this thesis investigates the nature and foundations of pastoralists??? responses to these changes and critiques. Through memory, history, labour and experience of land, non-indigenous pastoralists construct a narrative of land, themselves and others in which the presence of pastoralism in Central Australia is naturalised, and Central Australia is narrated as an inherently pastoral landscape. Particular types of environmental knowledge and experience, based in actual environmental events and processes form the foundation for a discourse of pastoral property rights. Pastoralists accommodate environmental concerns, through advocating environmental stewardship. They do this in such a way that Central Australia is maintained as a singularly pastoral landscape, and one in which a European, or ???white???, frame of reference continues to dominate. In this way the domesticated pastoral landscapes of colonialism and nationalism are reproduced. The thesis also examines Aboriginal pastoralism as a distinctive form of pastoralism, which fulfils distinctly Aboriginal land use and cultural aspirations, and undermines the conventional meaning of ???pastoralism??? itself. The thesis ends by suggesting that improved dialogue over rangelands futures depends on greater understanding of the details and complexities of local relationships between groups of people, and between people and land.
11
Edvantoro, Bagus Bina. "Bioavailability, toxicity and microbial volatilisation of arsenic in soils from cattle dip sites." Thesis, 2000. http://hdl.handle.net/2440/110365.
Повний текст джерела
12
Mandleni, Busisiwe. "Impact on climate change and adaptation on cattle and sheep farming in the Eastern Cape Province of South Africa." Thesis, 2011. http://hdl.handle.net/10500/5477.
Повний текст джерелаАнотація:
This study focused on the impact of climate change and adaptation on small-scale cattle and sheep
farming in the Eastern Cape province of South Africa. Using information from 500 livestock farmers
between 2005 and 2009 farming season, three methods of analysis were used to determine impacts of
climate change and adaptation. They were Principal Component Analysis (PCA), Binary Logistic
Regression Model (BLRM) and Heckman Probit Model (HPM). Findings revealed that cattle
production decreased during the study period 2005 to 2009. Preliminary descriptive statistics results
indicated that farmers had different perceptions on climate change and adaptation measures between
the periods 2005 and 2009. Further analysis using PCA showed that the different perceptions could
be grouped into: (i) drought and windy weather patterns; (ii) information and adaptation; (iii) climate
change extension services; (iv) intensive cattle and sheep production; and (v) temperatures. The
results of the BLRM indicated that the most significant factors that affected climate change and
adaptation were: (i) non-farm income per annum; (ii) type of weather perceived from 2005 to 2009;
(iii) livestock production and ownership; (iv) distance to weather stations; (v) distance to input
markets; (vi) adaptation strategies and (vii) annual average temperature. From the HPM the results
indicated that marital status, level of education, formal extension, temperatures and the way in which
land was acquired, significantly affected awareness on climate change. Variables that significantly
affected adaptation selections were gender, formal extension, information received on climate
change, temperatures and the way in which land was acquired.It was concluded that in the area of study, change in climate was already perceived by small-scale
cattle and sheep farmers. Households that perceived differences in seasonal temperatures during the
survey period were less likely to adapt to climate change. Having access to extension services
increased the likelihood of adaptation to climate change. Information on climate change to improve
livestock production appeared to play a significant role in the selection of adaptation measures. The
recommendation was that government should consider cattle and sheep farmers’ perceptions on
climate change when deciding on programmes for cattle and sheep production. It further suggested
that the most significant factors that affected climate change, adaptation, and awareness and
adaptation selections be considered when adaptation programmes are planned.Agriculture Animal Health and Human Ecology
D.Phil. (Environmental Management)
13
Chipfupa, Lukas. "The effects of weather variability on growth potential of Afrikaner cattle in a semi-arid region in Zimbabwe." Diss., 2012. http://hdl.handle.net/10500/10198.
Повний текст джерелаАнотація:
Only part of the abstract could be included due to the rest having renderable textThe abiotic environment plays an important role in cattle production. Key abiotic elements evaluated in this study are rainfall and temperature. This study was carried out to assess the effect and contribution of rainfall and temperature, amid other factors, on pre- and post-weaning growth traits of Afrikaner cattle at Matopos Research Institute from 1958 to 1997. Historical data generated from a genotype x environment interaction study at Matopos Research Institute was used to identify factors associated with the average daily weight gain of calves of Afrikaner cattle breed. A total of 10 700 records were retrieved comprising of birth weight (BW), 90 day weight, 205 day weight and early post-weaning weight as well as additional corresponding rainfall and temperature data from 1958 to 1997. The rainfall and temperature data was computed asrainfall and temperature variability. The data was corrected for heteroscedasticity using the generalized least squares approach (GLS) before running an ordinary least square regression (OLS) analysis to determine the association between growth rate and potential explanatory factors for average daily weight gain, pre-weaning weight gain and early post-weaning weight gain.
Agriculture and Animal Health
M. Sc. (Agriculture)
14
Walburger, Kenric. "The effects of timber harvest and herbivory on understory vegetation and composition of beef cattle diets on forested rangelands." Thesis, 2005. http://hdl.handle.net/1957/29756.
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15
Mukhuba, Mashudu. "Ecological guild of microbes that drive production of biogas from multiple feedstock." Diss., 2017. http://hdl.handle.net/10500/24518.
Повний текст джерелаАнотація:
Anaerobic digestion (AD) is becoming a widely adopted technology for conversion of organic waste and nutrient-rich fertiliser production due to its cost-effectiveness and sustainability. In this study, a batch experiment was conducted using five different types of food waste and cow dung (CD). No significant difference was observed among the four substrates that produced the highest methane (P<0.05). Based on the batch experiment results, two substrates were selected for semi-continuous digestion and the highest methane yield (67%) was obtained from co-digestion (CO). PCR-DGGE results revealed higher bacterial and archaeal diversity indices in CO as compared to mono-digestion of CD and mixed food waste. The high-throughput sequence analyses revealed that the Operational Taxonomic Units (OTUs) belonging to the phyla Bacteroidetes, followed by Firmicutes, Actinobacteria and Proteobacteria, were dominant in all treatments. The enhanced methane production in CO could be attributed to the neutral pH and partial shift of archaea from Methanosaeta to Methanosarcina. The digestate and fresh CD were screened for plant growth promoting bacteria (PGPB), nutrient and heavy metal content. The dung contained higher concentrations of heavy metals (P<0.05) and potential pathogens in comparison to the digestate. The use of digestate may, therefore, enhance soil fertility with minimal negative environmental effects.School of Agriculture and Life Sciences
M. Sc. (Life Sciences)