Selection intensity and generation interval were evaluated in a Hereford cattle herd made up of 14 inbred lines and 14 linecross groups corresponding to the lines of inbred sires at the Suan Juan Basin Research Center, Hesperus, Colorado. Selection indexes practiced were calculated in retrospect. Analyses of the records collected from 1946 through 1973 involved weaning weight (WW) and postweani...

Hereford cows were randomly bred to Hereford, Angus, Simmental X Hereford and Simmental sires. Each sire breed group was represented by nine or 10 sires. These matings produced approximately 100 calves in each sire breed group over 4 yr. The objective of this study was to determine the effect of calf breed on characteristics of the cow such as milk production, reproduction, measures of conditio...

The proportion of variance for service sire effect was estimated for three litter size traits (numbers of piglets born, born alive, and weaned) in Czech Large White (89 231 litters) and Czech Landrace (28 320 litters) pigs. Each trait in the first parity was considered as one trait and that trait in the second and subsequent parities was treated as a repeated trait. Consequently, three two-trai...

In genetic improvement programmes for beef cattle, the effect of selecting for a given trait or index on other economically important traits, or their predictors, must be quantified to ensure no deleterious consequential effects go unnoticed. The objective was to compare live animal measurements, carcass composition and plasma hormone and metabolite concentrations of male progeny of sires selec...

Parental behaviors involve complex social recognition and memory processes and interactive behavior with children that can greatly facilitate healthy human family life. Fathers play a substantial role in child care in a small but significant number of mammals, including humans. However, the brain mechanism that controls male parental behavior is much less understood than that controlling female...

Records (2,910) of birth (BWT), weaning (WW), and yearling weight (YW) of F1 calves produced in a top-cross experiment involving Angus, Hereford, Pooled Hereford, Charolais, Limousin, Simmental, Gelbvieh, Maine-Anjou, Chianina, Tarentaise, Shorthorn, and Salers bulls mated to Hereford and Angus cows and records (4,592) of WW on three-breed-cross calves out of 986 F1 females of the same breed cr...

Texel sheep were imported from Finland and Denmark for evaluation as a terminal sire population relative to the Suffolk breed. The objective was to estimate effects of sire breed on fitness, growth, and compositional traits of crossbred progeny that were serially slaughtered at 63, 105, 147, and 189 d of age. A total of 325 lambs, sired by 19 Texel and 20 Suffolk rams, were born to mature, half...

The objective of this study was to identify twinning rate quantitative trait loci (QTL) by typing pooled samples in a preliminary screening followed by interval mapping to test QTL effects. Four elite North American Holstein half-sib sire families with high twinning rate predicted transmitting abilities (PTA) were used in this study. Chromosomes 5, 7, 19 and 23 were not genotyped as these chrom...

A joint sire and cow evaluation for selected type traits has been carried out for the Canadian Holstein population using an individual animal model accounting for all known relationships. Only first lactation, first classification linear records were utilized. Linear scores for final class/final score (combined), feet and legs, mammary system, and stature were analyzed. The model of analysis in...

Parentage analysis, employing five hypervariable microsatellite markers, was used to follow spawning patterns of red drum Sciaenops ocellatus broodfish in two spawning tanks through most of a calendar year in a marine fish hatchery dedicated to stock enhancement. Five of six dams and all four sires spawned at least once during the year. Variation in dam and sire spawning incidence and in number...