Magnitude of correlation between direct and maternal genetic effects for growth traits in ruminants

This is a review paper that looks at the influence of sign and magnitude of the correlation between direct and maternal genetic effects for growth traits in sheep, goats and cattle. Considerable debate exists about the validity of results on the factors which influence the sign and magnitude of the correlation between direct and genetic effects of growth traits in sheep, goats and cattle. The current reports on sign and magnitude of the correlation between direct and maternal effects for growth traits in sheep, goats and cattle show that both positive and negative values are possible. It emerged that the use of an appropriate covariance of direct and maternal genetic effects for growth traits in sheep, goats and cattle has a bearing on the accuracy of selected programs. The importance of correlation between direct and maternal effects for growth traits in sheep, goats and cattle is based on the notion that ignoring the covariance of direct and maternal genetic effects for growth traits in sheep, goats and cattle may distort the ranking of individual animals in a population. The review paper therefore, concludes that the sign and magnitude of covariance of direct and maternal genetic effects for growth traits in sheep, goats and cattle, is dependent on various factors which include management, breed and data preparation process.