Milk production from diets of silage and dried forage. 1. Effects of methods of processing dried grass and of including barley in the supplementation of grass silage given ad libitum

Abstract

SUMMARY1. Young adult and adult British Friesian female cattle (heifers and cows) which were lactating were individually fed on diets of grass silage ad libitum with supplements of dried grass, dried grass/barley or barley/groundnut in two randomized block experiments.2. In Experiment I, equal quantities of dry matter (DM) as dried grass in the form of a wafer (W), cob (C) or pellet (P) were given with the silage during weeks 8 to 18 of lactation, to three groups of 12 heifers. Silage DM intakes were respectively 14·2, 14·3 and 15·8 ± 0·43 g/kg live weight per day (P<0·05). Milk yields were 14·0, 15·6, 16·7 ± 0·35 kg/day (P< 0·001). Milk composition and live-weight change did not differ significantly.3. In Experiment II, five treatment groups of heifers and cows were offered silage with equal amounts of a supplement of either dried grass pellets (treatment 1) or dried grass/barley in the ratios of 2: 1 (treatment 2), 1: 2 (treatment 3), or a barley/groundnut supplement (treatment 4). In treatment 5 the cattle received the same supplement as in treatment 4, but at a 10% higher level. Silage DM intakes for treatments 1 to 5 during lactation weeks 6 to 22 were 8·64, 8·94, 7·96, 6·96, 7·63 kg/day (1, 2>4, P<0·01; 2>5, P<0·05). The intake of digestible organic matter, milk yields and live-weight changes over the whole experimental period were not influenced significantly by treatments 1 to 4, but in treatment 5 the milk was significantly higher in fat, protein and energy content than in treatments 1 to 4. Blood composition was normal and did not differ markedly between treatments.