Two growth models to estimate economic values for food intake capacity in pigs

Abstract

Abstract Economic values for average ad libitum food intake capacity (FIC) were estimated with two different linear-plateau models. One model based on a constant minimum fat to protein deposition ratio (Rmin). The other model relied on a constant minimum marginal ratio between fat and protein deposition (MR). Economic values were used to define aggregate genotypes where the driving variables of the growth models were considered as traits. The consequences of a possible implementation of such aggregate genotypes were evaluated with a comparison of the expected selection responses for the different traits. Economic values for the traits under the two models indicated the same direction of selection and differed only slightly in their magnitude. For a FIC below its optimum, FIC had a positive and Rmin or MR a negative, economic value. In this situation the maximum protein deposition rate Pdmax had no influence on the production costs and therefore an economic value of zero. Selection emphasis is then mainly put on FIC which leads to an increase in average daily gain (ADG). If FIC is above its optimum, economic values for FIC were negative, positive for Pdmax and equal to zero for Rmin or MR. Practically no differences between the selection responses under the two growth models were observed. The use of growth models to estimate economic values for FIC allowed to attribute a positive economic value to this trait if it is below its optimum. This is not possible when economic values are estimated with an economic production model.