the present study was conducted to estimate genetic parameters and genetic, environmental and phenotypic trends of milk production traits in holstein cattle of hamedan province. in this study 11986 305-d records of first three parities of hamedan province holstein cattle, which were gathered during 1990-2011, were used. variance-covariance components and breeding values were estimated using ani...

Estimates of (co)variance components and genetic parameters were obtained for birth, 205-d, and 365-d weight for Nelore cattle in Brazil, using single and multiple-trait animal models. Data were from the Brazilian Zebu Breeders Association (ABCZ). Records of 27,549 calves sired by 587 bulls and raised on pasture in 57 herds were analyzed by restricted maximum likelihood fitting an animal model ...

Estimating (co)variance parameters of a random regression model for test day yields of dairy cattle has been proven to be a challenging task due to the complexity of (co)variance structure of the test day yields. Two common approaches have been practised so far for the estimation of parameters: direct random regression model approach and indirect covariance functions (CF) approach. Animal genet...

(Co)variance components and genetic parameters were estimated for body weights of a Romosinuano herd located in Sinú Valley, Cordoba, Colombia. Restricted maximum likelihood methods were used with a univariate animal model for birth weight, weaning weight (270 days), 16-month weight (480 days), weaning daily gain, and post-weaning daily gain. Models included random animal direct and maternal ge...

Data from a multibreed composite beef cattle population, managed under intensive irrigated grazing conditions, were used to estimate direct additive heritabilities (ha), maternal heritabilities (h 2 m) and maternal permanent environmental effects (c) for birth weight (BW) and weaning weight (WW) of the calf and cow efficiency of the dam (CE: WW/dam weight x 100). Calves born between 1968 and 19...

Lactation means of somatic cell scores from sample days were used to estimate the components of variation for additive genetic, permanent environmental, and herd-sire interaction effects. Data included records of 4314 Ayrshire, 7845 Brown Swiss, 18,115 Guernsey, 1,135,752 Holstein, 67,862 Jersey, and 787 Milking Shorthorn cows from across the US. Records were preadjusted for length of lactation...

Estimates of genetic parameters were obtained from two samples of weights and heights of mature cows provided by the American Angus Association. The first sample consisted of 23,658 records for mature weight (MWT) and 13,012 for mature height (MHT) and the second sample consisted of 23,698 records for MWT and 13,310 for MHT. The four-generation pedigree file included 43,105 animals for the firs...

Data from the slaughter of 24,001 chickens that were part of a selection program for the production of commercial broilers were used to estimate genetic trend for absolute carcass (CW), breast meat (BRW), and leg (LW) weights, and relative carcass (CY), breast meat (BRY), and leg (LY) weights. The components of (co)variance and breeding values of individuals were obtained by the restricted maxi...

Data on litter production traits of does, involving 1120 litters, was collected over a 10-year period (1984 to 1994) and analyzed to estimate heritability and repeatability. Locally adapted does and bucks of predominantly New Zealand White breeding were involved. Traits studied were total litter size born and born alive, and litter size and weight at 21 days, 28 days (weaning) and 84 days (mark...