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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Genetic and phenotypic parameters of lifetime performance traits in Canadian Holsteins

Jairath, Lalit Kumar January 1992 (has links)
Estimates of genetic and phenotypic parameters of lifetime performance traits and estimates of correlations between these and first lactation traits were obtained using multitrait mixed model and Restricted Maximum Likelihood (REML) methodologies, and accounting for all known additive genetic relationships amongst animals in sires pedigree. Part-lifetime performance traits, i.e. two-, three, and four-parity totals of yield and profit, were also included in the analysis. Data were on 82,835 Holstein cows, daughters of 703 sires, calving first between September 1979 and December 1984 in the herds enrolled in Quebec Dairy Herd Analysis Service (QDHAS). Lifetime performance records, however, continued through December 1989. / Results of analysis indicated low estimates of heritability for lifetime performance traits, e.g., lifetime production and profit (.11$ sim$.13) and longevity (.07$ sim$.09). However, production per day of productive life traits had moderate heritability (.28$ sim$.32). Estimates of genetic and phenotypic parameters decreased from part-lifetime to total lifetime performance because residual variances increased at a greater rate compared to rate of increase in sire variances. Both genetic and phenotypic correlations amongst lifetime production, lifetime profit and longevity traits were very high and approached unity in all cases. / Estimates of genetic and phenotypic correlations of first lactation production and profit traits with all measures of part and total lifetime performance were positive and high. These correlations decrease from part-lifetime to total lifetime performance due to part to whole relationships. / Estimates of parameters of lifetime performance traits were mostly free of the effects of selection on milk production. Positive and high genetic correlation of first lactation milk yield with all lifetime performance traits indicated that selection on first lactation milk yield alone will improve all measures of lifetime performance. However, some consideration should be given to measures of reproduction and health which may help in improving the longevity of dairy cattle. (Abstract shortened by UMI.)
32

Identification of variants within the coding region and 5'-flanking region of the k-casein encoding gene in Holsteins using PCR-RFLP and PCR-SSCP analyses

Masoudi, Mehrnoush January 1996 (has links)
Single-strand conformation polymorphism analysis (SSCP) and restriction fragment length polymorphism analysis (RFLP) were used to determine the genotype of Holsteins at the $ kappa$-casein ($ kappa$-CN) locus. A 432-bp fragment within exon IV containing nucleotide substitutions diagnostic of the A- and B-variants of $ kappa$-CN was amplified using the polymerase chain reaction (PCR). The sires from the earliest years of the AI industry had a significantly higher (p $<$ 0.01) frequency of allele than sires in modern usage. These data indicate that selection or milk production parameters may discriminate against the B-allele. SSCP analysis was also used for detecting polymorphisms within the regulatory region of $ kappa$-CN gene. A 640-bp fragment within the 5$ sp prime$-flanking region of bovine $ kappa$-CN gene which contained the TATA box, CAAT box, and exon I was amplified using PCR. The SSCP analysis of this fragment revealed no variation, possibly due to the lower detection efficiency of SSCP with large fragment size. Nested primers were, therefore, designed to amplify fragments of 234- and 486-bp. Polymorphism was detected only in the 486-bp fragment and the two variants were designated M$ sb1$ and M$ sb2.$ The allelic frequencies of M$ sb1$ and M$ sb2$ in bulls used by AI industry before 1970 were 0.67 and 0.33, and in bulls used by AI industry after 1980 the frequencies were 0.68 and 0.32, respectively. The frequency of these alleles were not significantly different in Holsteins used by AI industry before 1970 and after 1980. Unlike the apparent change in frequency of the A- and B-variants noted within exon IV, this polymorphism seems to have not responded to selection. However, a higher frequency of M$ sb1$ allele appeared to be associated with B-variant (exon IV) genotypes. The presence of these variants within the regulatory region may possibly be involved in the quantitative expression of $ kappa$-CN gene. (Abstract shortened by UMI.)
33

Effect of naloxone on serum luteinizing hormone concentrations during the early postpartum period and the estrous cycle in primiparous and multiparous holstein cows /

Ahmadzadeh, Amin, January 1994 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 93-104). Also available via the Internet.
34

Effects of inbreeding and age at first calving on milk yield and failed services in first lactation of bST and non-bST treated Holstein cows

Geha, Makram J. January 2009 (has links)
Thesis (Ph.D.)--University of Nebraska-Lincoln, 2009. / Title from title screen (site viewed June 26, 2009). PDF text: v, 114 p. : ill. ; 1.05 Mb. UMI publication number: AAT 3352316. Includes bibliographical references. Also available in microfilm and microfiche formats.
35

Heritabilities and phenotypic and genetic correlations between type ratings and milk and butterfat production in Holstein-Friesian cattle

Mitchell, Ralph Gerald, January 1959 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1959. / Typescript. Abstracted in Dissertation abstracts, v. 19 (1959) no. 7, p. 1496-1497. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 60-63).
36

Studies of pulmonary function in the Holstein calf

Kiorpes, Anthony Lloyd, January 1977 (has links)
Thesis--Wisconsin. / Vita. Includes bibliographical references.
37

Connections between mastitis and climate a study of holsteins on pasture in Northampton County, Pennsylvania /

Drake, Dawn M. January 2008 (has links)
Thesis (M.S.)--University of Delaware, 2008. / Principal faculty advisor: Tracy DeLiberty, Dept. of Geography. Includes bibliographical references.
38

Variations in heritability and repeatability of milk, fat and percentage of fat yield in stratified Holstein-Friesian herds

Duckwall, James Ward, January 1963 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1963. / Typescript. Vita. With this is bound: Production performance of artificially and nonartificially sired herd-mates in Wisconsin / E.L. Corley, J.W. Duckwall, and E.E. Heizer. Reprinted from Journal of dairy science, vol. XLVI, no. 1 (Jan. 1963), p. 50-56. Includes bibliographical references (leaves 53-54).
39

Immunogenetic studies of cattle transferrins and blood groups

Datta, Surinder P. January 1963 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1963. / Typescript. Vita. With this is bound: The J substance of cattle : VII. Production of immune anti-J in rabbits / A, G. Bednefoff, S.P. Datta and W.H. Stone. Reprinted from Journal of immunology, vol. 89, no. 3 (Sep. 1962), p. 408-413. Includes bibliographical references.
40

Reliability of A.I. Holstein sire provings

Lindstrom, Ulf Bruno, January 1966 (has links)
Thesis (M.S.)--University of Wisconsin--Madison, 1966. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

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