Effects of pattern of concentrate feeding on milk production of dairy cows offered silage ad libitum.

Abstract

In three 24-wk experiments beginning at wk 4 post partum, a system of concentrate feeding at a flat level was compared with feeding concentrates to milk yield (experiments 1 and 2), or with a high-low 2-step system in which the rate was reduced after wk 12 (experiment 3). Roughage was offered ad lib. In experiment 1 two types of concentrates were involved whereas in experiment 3 two levels of concentrates were applied. The systems were evaluated using high levels of concentrates and with Friesian and Holstein-Friesian cows producing about 7000 kg milk/lactation. Experiments 1 and 3 involved 64 and experiment 2 32 cows. In the comparison between feeding strategies, differences in yield and composition of milk were of minor importance except for milk protein content on the moderate-quality grass silage diet (experiment 1). Milk production tended to be higher for concentrates including fish meal, in contrast to soyabean meal, particularly in the first half of the experimental period. However, milk fat content was significantly lower, resulting in similar productions of 4%-FCM. Extra concentrates in experiment 3 had significant positive effects on the production of milk, fat and protein, and also on milk protein content and liveweight gain. Feeding strategy however, was without any significant effect. It was concluded that with the high-yielding cows, offered roughages to appetite, there is no need to feed concentrates strictly to their estimated individual energy requirements. This may be of increasing importance when forage allowances/cow increase as a consequence of smaller numbers of cows/farm. (Abstract retrieved from CAB Abstracts by CABI’s permission)