Genetic and environmental trends in growth performance of a flock of Horro Sheep
2002
Solomon Abegaz (Ethiopian Agricultural Research Organization, Addis Abeba (Ethiopia))
Phenotypic, genetic and environmental trends in birth weight (BW), weaning weight (WW), six-month weight (GMW) and yearling weight (YW) were studied on data collected from a largely closed flock of Horro sheep kept at Bako Research Center during the period 1978-1997. Average Information Restricted maximum Likelihood (AIREML) program was used to solve linear mixed models for breeding value prediction. Regression of annual mean genetic, environmental, and phenotypic values on year was used to estimate trends. Genetic trends over the years showed increase with a slight decline starting in 1994. Environmental and phenotypic trends showed a large decline and fluctuating patterns. The small improvement in genetic level could not compensate for larger decreases in environmental levels suggesting that genetic improvement work should be supported by improved environmental.
显示更多 [+] 显示较少 [-]