The effect of level and type of concentrate and type of conserved forage on dry matter intake and milk production of lactating dairy cows

Abstract

SummaryBetween weeks 3 and 16 of lactation 191 British Friesians received a basal ration ad libitum of either grass silage (GS), grass and maize silage (GS/MS) blended in a ratio of 1:2 or grass silage and 4% NaOH-treated barley straw (GS/TS) blended in a 4:1 ratio. The grass silage, which was not well preserved, had an estimated metabolizable energy (ME) content of 9–9 MJ/kg D.M., while corresponding values for the GS/MS and GS/TS mixtures were 106 and 9–5 MJ/kg D.M., respectively. A conventional concentrate (CC) based on barley and soyabean meal was fed at three levels (9, 6 and 3 kg fresh weight/day). Although the 9 kg level was only used in conjunction with GS, the two lower levels were fed with all three forage types. Concentrate composition was also varied at the 6 and 3 kg levels by replacing, in each case, 2 kg CC with a special concentrate (SC) which, in addition to barley, wheat and soyabean meal contained, on an air-dry basis, 25 % fishmeal and 25 % protected fat in the form of Megalac