Variation in the complete diet composition given during the winter period to an autumn-calving herd

Abstract

SUMMARYAutumn-calving cows on a complete diet system were given a similar amount of concentrates over two winter periods in the years 1980–1 and 1981–2. Two feed allocation systems were examined: step (different diets given at different stages of lactation) and uniform (one single diet given over all the winter period).The yield of fat-corrected milk (FCM) was similar (P > 0·05) in both systems with 5·32 and 5·37 t/cow for the step and uniform system respectively in the 1st year and 4·75 and 4·35 t/cow in the 2nd year.There is an indication that adult cows or cows with a higher potential for yield can respond to the higher energy concentration diet given in early lactation but with the main effect on milk, not in FCM yield.No effect of diet distribution was found on overall weight gain but cows given the uniform system lost less weight in early lactation and this may lead to better conception for cows in such a system.