ECONOMIC VALUES OF TRAITS FOR PIG IMPROVEMENT .2. ESTIMATES FOR NEW-ZEALAND CONDITIONS

A computer model simulating life cycle production of a breeding sow an d growth performance of her offspring was used to estimate economic va lues of reproduction and growth performance traits. The model simulate d digestion and metabolism of dietary nitrogen in growing pigs (20 to 85 kg), based on the linear/plateau relationship between daily protein deposition and digestible energy intake. Economic values (EVs) of rep roduction and growth performance traits were calculated by simulating effects of genetic changes in several biological components, in a farr ow-to-finish production system, assuming ad libitum feeding. Results d emonstrated that economic values of traits depended on the average gen etic merit in the pig herd and its interaction with the management cir cumstances (level of feeding, nature of the diet, life cycle length) o f the production system.