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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 242 for “"herds"”.
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Production changes related to labor management in Virginia dairy herds
… of 321 randomly selected Virginia dairy herds was analyzed and labor data were combined with DHI records to determine for Holstein herds the relationship of labor management with subsequent enrollment in the Dairy Herd Improvement program, and the effect of labor management variables on …
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Relationships among financial and production records between and within dairy herds
… and farm profit between and within dairy herds. Herd effects were the largest source of variation (>45%) for most financial variables whereas year effects were smaller (<10%). Regressions within herds and years accounted for .7 to 8.5% and residual effects 8.6 to 56.8% of variation in …
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Abnormal Milk Evaluations in Eastern South Dakota Milk Plants and Dairy Herds
… in Eastern South Dakota and to identify those herds which were producing abnormal milk. However, there was no attempt made to define the causes related to the production of abnormal milk. The second part of this thesis presents the results of research with thirteen herds in Eastern South Dakota …
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Factors Influencing the Reproductive Efficiency of Dairy Herds in the Dominican Republic
… may help increase estrus detection efficiency in herds currently only relying on visual observation. Assigning 1-2 people primarily to estrus detection and increasing the frequency of hormone usage may also improve estrus detection efficiency. The main emphasis for Dominican dairy producers, …
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Health Surveillance of Thinhorn Sheep (Ovis dalli) Herds in British Columbia and Alaska
… assessments of thinhorn sheep in five study herds across their range that included both subspecies, Dall’s sheep (O. dalli dalli) and Stone’s sheep (O. dalli stonei). We used a broad definition of health and surveyed exposure to multiple pathogens common to domestic small ruminants and other …
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Factors affecting the accuracy and stability of sire proofs from progeny test herds
… of first crop and non-first crop cows in 3449 herds participating in the AI stud's young sire sampling program from 1971 to 1987 were used to characterize the sampling program, to estimate genetic trend across and within the progeny test herds, and to compute within herd means and standard …
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Transmission Dynamics Of Mycobacterium Avium Subspecies Paratuberculosis In Closed Dairy Herds In The Us
… played an important role in MAP persistence in herds undergoing intervention attempts. Adding age- and dose-dependent early shedding created a forward feedback loop in which MAP can persist in populations which would not support introduction.
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Development of tropical-adapted herds facilitated by the use of dominant follicle removal technique
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2023-12-04 without embargo terms
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The herds shot round the world : native breeds and the British Empire, 1800-1900
This dissertation explores the relationship between types of livestock and place in the context of Great Britain's expanding agro-pastoral empire. Specifically, it examines how the distribution and circulation of breeds of livestock native to the British Isles influenced understandings of kind and …
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Comparison of Neospora seroprevalence in Virginia dairy herds with high and low abortion rates
… outbreaks with rates exceeding 30% in some herds. Cows infected with this organism exhibit no other clinical signs. While this disease has been reported in other parts of the country, no assessment of Neospora seroprevalence has been undertaken in the Southeast. This study sampled commercial …
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Surveillance in contemporary swine herds - the case of porcine reproductive and respiratory syndrome virus (PRRSV)
… but not in samples collected in commecial herds. In contrast, IgG was readily detected at diagnostically useful levels in both experimental and field samples for up to 126 days (duration of the study). Estimates of the IgG oral fluid ELISA performance were based on results from testing …
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Characteristics of progeny test herds and their effects on the genetic evaluation of young sires
… was to examine characteristics of progeny test herds and their effects on the genetic evaluation of young sires. Data for a study of response to pedigree selection by stud were evaluated from 6238 Holstein sires in four USDA animal model evaluations from January 1995 to February 1997. When data …
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An Investigation of Risk Factors for the Spread of Pseudorabies (Aujeszky's Disease) in Illinois Swine Herds
… of the spread of pseudorabies virus among swine herds were examined: a spatial analysis at two levels (the county level and the individual farm level) and a case-control study of pseudorabies virus (PRV) in Illinois swine herds.
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Two Layers of Selfish-Herds in Spawning Aggregations of Chub (Nocomis Sp.) and its Nest Associates
Many species have evolved to live in groups. Gregarious behavior was believed to be adaptive for whole-population survival and predator evasion until selfish-herd theory was introduced. It proposed that individuals congregate not as a method of protection for the entire population, but instead to …
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Prevalence and risk factors of GIARDIA infections in Dairy Cattle Herds in Lusaka and Chilanga Districts of Lusaka
… the prevalence of Giardia infections in dairy herds on farms in Chilanga and Lusaka districts of Lusaka Province, Zambia, and to evaluate risk factors associated with the infections. Farms were grouped into smallholder and commercial farms. A total of 377 calves aged one day to one year were …
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Prevalence and risk factors associated with Trypanosomosis in Cattle Herds in Kilwa District of Lindi Region of Tanzania
… from 420 cattle randomly selected from 86 herds from ten villages. A maximum of ten herds per village and at maximum six animals from each herd were selected for sampling. At the same time a questionnaire was administered. Individual animal samples were analysed using microscopy and pooled …
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Prevalence and risk factors of GIARDIA infections in Dairy Cattle Herds in Lusaka and Chilanga Districts of Lusaka
… the prevalence of Giardia infections in dairy herds on farms in Chilanga and Lusaka districts of Lusaka Province, Zambia, and to evaluate risk factors associated with the infections. Farms were grouped into smallholder and commercial farms. A total of 377 calves aged one day to one year were …
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Prevalence and risk factors associated with Trypanosomosis in Cattle Herds in Kilwa District of Lindi Region of Tanzania
… from 420 cattle randomly selected from 86 herds from ten villages. A maximum of ten herds per village and at maximum six animals from each herd were selected for sampling. At the same time a questionnaire was administered. Individual animal samples were analysed using microscopy and pooled …
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Development of a plant-made immunoassay for the detection of Porcine circovirus infections in South African swine herds
… to be able to test for PCV infection in pig herds. Production of PCV-2 CP in Nicotiana benthamiana via transient Agrobacterium-mediated expression was optimised by comparing two expression vectors, pEAQ-HT and pCBP2, and VLPs were also expressed in Escherichia coli. VLPs produced in plants …
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Effects of using an enzyme-linked immunosorbent assay to monitor the control of Staphylococcus aureus mastitis in dairy herds
… preserved milk samples in 10 Virginia cooperator herds. Herds were classified as high (>10% infected) or low prevalence (<10% infected). There were six high prevalence herds after the first test. Average prevalence of cows scoring Ab +2 and +3 was 11.9% ± 7.9. Over the seven month study, …
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