Thesis - University Access Only
Master of Science (MS)
Department / School
Donald M. Marshall
Cows producing calves from 1991 to 1995 (n=288) were genotyped (PCR-RFLP) at the κ-casein and β-lactoglobulin loci and evaluated for pre-weaning calf growth traits and cow milk yield. A mixed linear model with fixed effects of κ-casein or, β-lactoglobulin genotype; year; breed-group; calf breeding system; sex; linear covariates of age of cow in years and age of calf in days; and a random sire of cow effect nested within breed was used to evaluate annual milk yield (MY) and calf birth weight (BWT), weaning weight (WWT), and pre-weaning average daily gain (ADG) at 53 days (pre-ADG1), 109 days (pre-ADG2), and 211 days (pre-ADG3) of age as traits of the cow. Sire and error variances were estimated from the data using multiple trait derivative-free restricted maximum likelihood (MTDFREML). κ-casein effects were detected for pre-ADG2 (P < .01), pre-ADG3 (P < .05), and WWT (P < .05). Effects of allele substitution (B alleles replaced by A alleles) approached significance (P < .10) for pre-ADG3 and WWT and was significant for pre-ADG2 (P < .05). Dominance effects were significant for pre-ADG2 (P < .01) pre-ADG3 (P < .05), and approached significance for WWT (P < .10). A breed by κ-casein genotype interaction was significant for MY (P < .01). A breed by genotype interaction was significant for both MY (P < .01) and approached significance for pre-ADGl (P < .10) at the, β-lactoglobulin locus. The cow genotype effect at the, β -lactoglobulin locus was significant for pre-ADG2 (P < .01) and additive and dominance effects were also significant (P < .05 and P < .01, respectively). The effect of cow genotype on pre-ADG3 approached significance (P < .10) for pre-ADG3 at the, β-lactoglobulin locus and the dominance effect approached significance as well.
Library of Congress Subject Headings
Cattle -- Genetics
Calves -- Growth
Number of Pages
South Dakota State University
Henderson, David, "κ-Casein and β-Lactoglobulin Genotype Effects for Milk Production and Maternal Calf Growth Traits in a Crossbred Cattle Population" (1996). Electronic Theses and Dissertations. 170.