A study was conducted to determine the effect of serving capacity (SC) on sexual behavior of yearling bulls during single- and double-sire pasture matings. Approximately 60 crossbred virgin bulls were subjected to 3 SC tests, and 20 bulls were selected that were similar in age, BW, testes size and semen quality. Ten bulls were high SC (greater than or equal to 3 services/test) and 10 bulls were...

Theoretical weights for prediction of a son's genetic evaluation from genetic evaluations of his sire and dam are derived. Weights for sire and dam are equal and depend on number of daughters of the son when the bull evaluation is from his daughters alone and cow evaluation is from her records alone. Mixed model procedures which incorporate records of other relatives change theoretical weights....

Twelve Hereford bulls were used to sire calves in each of three locations in North Carolina over 6 yr. Three bulls were bred artificially to a random one-third of the cows at each location each year. Locations represented the Mountain, Piedmont and Coastal Plain regions of the Southeast. As yearlings, steer progeny were fed a concentrate diet in a feedlot or grazed on pasture and then slaughter...

Gestation length, birth weight calving difficulty, calf mortality rate at birth, calf mortality rate from birth to weaning, preweaning calf growth rate and calf 200-d weight were evaluated in a biological type study in which four sire breeds were bred by AI to Hereford dams. Angus and Red Poll sires represented breeds of medium size, and Pinzgauer and Simmental sires represented large breeds. A...

The objective of this study was, by means of simulation, to quantify the effect of ignoring individual heterogeneity in Weibull sire frailty models on parameter estimates and to address the consequences for genetic inferences. Three simulation studies were evaluated, which included 3 levels of individual heterogeneity combined with 4 levels of censoring (0, 25, 50, or 75%). Data were simulated ...

The genetic model for fetal effect on production of the dam is described, and studies on genetic and economic implications are reviewed. The effect on production from the sire of the cowhas 1.58 to 3.02 times as much economic value as the effect from the sire of the fetus. The use of mate records in evaluating a sire in addit ion to daughter records could increase economic gain from selection b...

The objectives of this study were to estimate genetic parameters and sire breeding values for average daily gain (ADG) and carcass traits using sire-maternal grandsire model with REML approach, sire model with REML approach, sire model without relationships among sires and with REML and ANOVA approach, and to investigate advantages and disadvantages of these methods. Data were collected from 42...

the main objective of this study was to estimate the genetic parameters for multi-trait evaluation of birth weight (bw), gestation length (gl) and calving difficulty (cd) in first-parity iranian holstein dairy cattle. the data included 29,950 calving records collected during 1995 to 2014 by the animal breeding and improvement center of iran. a threshold-linear sire-maternal grandsire model was ...

The nature of the heterogeneity of variance for 200- and 365-d weights by sex, sire breed, and dam breed subclasses was studied. Data consisted of records for weaning (n = 7,829) and yearling (n = 7,367) weights of progeny from 673 and 672 sires, respectively, from 22 breeds that have been evaluated in the Germ Plasm Evaluation Program at the U.S. Meat Animal Research Center, Clay Center, NE. S...