Six Different Models for Estimation of Genetic Parameters and Breeding Values for Pre-weaning and Post-weaning Weights in Suckler Cattle

Authors : Zafer ULUTAŞ

Pages : 179-184

View : 12 | Download : 4

Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :Estimates of insert ignore into journalissuearticles values(co);variance components and breeding values for pre-weaning insert ignore into journalissuearticles values(100-day); and post-weaning insert ignore into journalissuearticles values(300-day); weights were obtained for a commercial herd of Welsh Black cattle recorded from 1976 to 1996. Estimates were obtained from six animal models ranging from a model with only an additive direct effect to a model that also included an additive maternal effect, a maternal permanent environmental effect and a covariance between additive direct and additive maternal effects. The most appropriate model for 100-day weight, based on a likelihood ratio test, was a model with additive direct and additive maternal effects with no covariance between them, yielding estimates of 0.25 insert ignore into journalissuearticles values(0.053); and 0.07 insert ignore into journalissuearticles values(0.025); for h2 and m2 respectively. For 300-day weight, the model with only an additive direct effect was the most appropriate with an h2 of 0.27 insert ignore into journalissuearticles values(0.050);. Trends in additive direct breeding values for 100-day and 300-day weights were 0.39 insert ignore into journalissuearticles values(0.029); and 0.96 insert ignore into journalissuearticles values(0.077); kg per annum respectively. Additive maternal breeding values for 100-day weight increased by 0.08 insert ignore into journalissuearticles values(0.008); kg/annum. A correlation of 0.77 insert ignore into journalissuearticles values(0.066); was estimated between additive direct effects for 100- and 300-day weight.
Keywords : Welsh Black cattle, genetic parameters, maternal effects, genetic trend