Genetic components of potential and actual growth

Abstract

1. It is shown how the growth of an animal in non-limiting conditions can be predicted from the values of a small set of animal variables. The functions used are derived from a small set of simple, and reasonable, assumptions.2. Growth may be limited by intakes of nutrients and energy which are less than those needed. The prediction of growth where such limitation occurs calls for the prediction of the intakes. There may be genetic variation in the abilities of animals to deal with the relevant constraints which are, commonly, feed bulk or hot environments.3. Breeders need to pay more attention to giving sufficient descriptions of their stocks.