Estimation of genetic parameters for growth, carcass and overfeeding traits in a white geese strain.
In an experimental strain of white plumage geese created in 1989, 2 experiments were carried out during 1993-95 in order to estimate genetic parameters for growth, and carcass composition traits in non-overfed animals, and genetic parameters for growth and fatty liver formation in overfed animals. 431 non-overfed animals were bred and slaughtered at 11 weeks of age; they were measured for forearm length, keel bone length, chest circumference and breast depth before and after slaughtering. The carcasses were partly dissected in order to weigh breast, breast muscle and skin + fat, and abdominal fat. 477 overfed animals were slaughtered at 20 weeks of age; they were measured for 'paletot' (breast meat, bone and meat from wings, bone and meat from thigh and legs) weight and liver weight. In the 2 experiments, the weights had moderate to high heritability values. Breast depth measured on live animals showed a low heritability value. In overfed animals, liver weight showed a high heritability value. Liver weight could be increased by selection without a great effect on 'paletot' weight. Thus, obtaining a white plumage geese strain for fatty liver production by selection would be difficult because only 20% of overfed animals had fatty liver. No conclusion could be reached on the influence of selection on liver weight or carcass traits such as muscle or fatty tissue weight.