Published online by Cambridge University Press: 27 February 2018
In an effective animal breeding programme the objectives are appropriate, the population structure is good, suitable records are collected, and these records are used in an optimal way so that animals likely to have the best offspring are chosen.
Estimates of genetic parameters such as heritabilities and correlations influence the design of the programme: for example, the optimal number of daughters to progeny test per dairy sire or, more fundamentally, whether to adopt performance or progeny testing, whether to record food conversion efficiency or simply growth rate, and whether or not to collect records on some indicator trait such as blood urea nitrogen level. The estimates of parameters also influence the weightings given to different traits and to individuals and relatives' performance in breeding value estimation and selection. Methods for estimating parameters have become much more sophisticated as a result of advances in theory, particularly, restricted maximum likelihood (REML), in computer power, and in development of special computer programs.