Economic value of residual feed intake in dairy cattle breeding goals

In the Nordic countries of Denmark, Finland, and Sweden, a breeding value for Saved feed is targeted. Saved feed consists of two sub-traits, maintenance and metabolic efficiency, which are evaluated as residual feed intake. This study evaluated residual feed intake in relation to calculated economic values to set breeding goal. Residual feed intake typically is derived using phenotypic or genetic regression. However, when calculating economic value (EV) for residual feed intake, phenotypic and genetic residual feed intake save feed, and so are not relevant; yet, EV is important for the genetic progress of such traits. Thus, phenotypic regression coefficients were used to obtain the economic value of residual feed intake in the current simulation. The SimHerd model was used in this study to quantify the EV of RFI. The economic value of phenotypic residual feed intake ranged from 0.16 to 0.18 euro/kg dry matter, corresponding to 0.16 to 0.18 euro/Scandinavian feed unit (SFU - 1 SFU corresponds to 0.97 kg dry matter and 6.7 mega joule net energy) in the SimHerd simulation. Thus, the economic value of feed efficiency corresponded to the applied feed price in the simulations (0.18 euro/SFU). By splitting phenotypic residual feed intake into two periods (before and after 84 days in milk), we showed that the simulation of biological changes during early lactation showed that the economic value was not dependent on (P 0.05) residual feed intake being modelled as one or two periods. However, profit per annual cow differed significantly between simulations using one or two residual feed intake periods (P < 0.001). In conclusion, it is very important to select the appropriate the method to estimate breeding values for residual feed intake.