The prediction of the voluntary feed intake of dairy cows

Abstract

SUMMARYInformation on the total dry-matter intake (TDMI), concentrates supplied (C), live weight (LW), week of lactation (WL), milk yield (MY) and composition, quality of forage fed to, and parities of, 385 cows from five different sources were assembled to develop appetite prediction equations. The equations were based on multiple regression and least squares constants and were calculated using the data from each source and the data pooled from all sources. The major factors affecting total dry-matter intake (TDMI) were C, LW, WL and MY and for the pooled data these factors explained 73–76% (R2) of the total variation in TDMI. The predictive values of some of the equations were tested against independent sets of data and for groups of cows and individual cows, the equations predicted TDMI within ±1·1 and 1·6 kg, respectively. The application of the equations in the field is discussed and some suggestions made for increasing the R2 of future appetite equations.