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, two exper iments were carried out from 1993 to 1995 in order to estimate genetic para meters for growth, and carcass composition traits in non-overfed animals, a nd genetic parameters for growth and fatty liver formation in overfed anima ls. Four hundred and thirty-one non-overfed animals were bred and slaughter ed at 11 weeks of age; they were measured for forearm length, keel bone len gth, chest circumference and breast depth before and after slaughtering. Th e carcasses were partly dissected in order weigh breast, breast muscle and skin + fat, and abdominal Eat. Four hundred and seventy-seven overfed anima ls were slaughtered at 20 weeks of age; they were measured for "paletot" (b reast meat, bone and meat from wings, bone and meat from thigh and legs) we ight and liver weight. In these two experiments, the weights had moderate t o high heritability values. Breast depth measured on live animals showed a low heritability value. In overfed animals, liver weight showed a high heri tability value. Liver weight could be increased by selection without a grea t 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. The results did not allow to conclude on the influence of selection on liver weight on carcass traits such as mus cle or fatty tissue weight.