Genomic scans were conducted with 273 markers on 181 sires from a cattle population selected for increased twinning rate to identify chromosomal regions containing genes that influence ovulation rate. Criteria used for selecting markers were number of alleles, ease of scoring, and relative position within linkage group. Markers were multiplexed or multipleloaded on the gels to reduce the costs ...

Group effects are used in sire evaluation models to account for genetic trend. The objective of this paper was to develop definitions of these group effects where sires are related. Definitions were obtained for sire groups from results of a set of modified mixed model equations. Definitions were functions of genetic selection differentials. Definitions were dependent on the matrix of numerator...

(Co)variance component estimates were computed for retail cuts per day of age (kilograms per day), cutability (percentage of carcass weight), and marbling score (1 through 11) using a multiple-trait sire model. Restricted maximum likelihood estimates of (co)variance components were obtained via an expectation-maximization algorithm. Carcass data consisted of 8,265 progeny records collected by U...

Animals with the same lactation breeding value can have different shapes of additive genetic curve, implying differences in persistency lactation. Since environmental conditions change across lactation, animals re-rank through leading to genotype by environment interaction for daily milk yield. The objectives this project is describe curve pattern estimated values and assess extent sire cow re-...

Excellent reviews of cattle breed comparisons or breed-cross comparisons have been previously reported by Franke (1980), Long (1980), and Marshall (1994). However, these reviews do not contain information on the calving ease, performance, carcass characteristics, or beef palatability of crossbred progeny of Holstein dams sired by different beef breeds. In many countries dairy females are common...

Genetic evaluations for milk yield of Holsteins in Mexico were computed from lactation and pedigree information from Holstein de México. The US animal model system for national evaluations was adapted for Mexico. The primary change was in defining unknown-parent groups. Paths of unknown parents of bulls and sires of cows were combined and separate unknown-parent groups defined for parents of US...

_______________________________________________________________________________________ Abstract Pedigree and race run data from Thoroughbreds racing in Southern Africa, covering the period 19862002 (63 146 horses in pedigree data-set and 778 532 race runs), were analysed in order to study genetic and environmental factors affecting the incidence of epistaxis as associated with “exercise-induce...

For modern cattle industry, it is very important to evaluate bull-sires of different breeds by semen quality. The relevance this problem arises in the context development artificial insemination technologies and biotechnology, increasing role sire-bulls genetic improvement herd, which makes possible significantly change breed composition herds large regions a short period time. In breeding, sir...

Postweaning growth, puberty, and pregnancy traits were evaluated for 783 F1 heifers sired by Angus, Hereford, Charolais, Shorthorn, Galloway, Longhorn, Nellore, Piedmontese, and Salers bulls and out of Angus and Hereford dams in Cycle IV of the Germplasm Evaluation (GPE) Program at the U.S. Meat Animal Research Center. The Hereford and Angus sires included a sample of bulls born from 1982 to 19...