Application of mixed model methodology in breeding strategies for laying fowl

The main objective of this review is to present the advantages and disadvantages of applying the best linear unbiased prediction (BLUP) procedure with an animal model to the evaluation of laying fowl within a breeding programme. Following an outline of the traditional selection index-based procedure there are descriptions of mixed model methodology including modelling and data transformation, genetic parameter estimation and breeding value prediction. Some computer programs for carrying out BLUP animal model algorithms are described and the results of empirical and simulation comparisons involving different livestock species are given. New possibilities arising from the application of the animal model to breeding strategy are discussed. Poultry breeding evaluations using the traditional selection index do not always result in the same conclusions as arise when using BLUP. However it seems likely that, as has happened with other livestock species, the BLUP animal model method will be increasingly applied in breeding programmes to improve egg production.