Comparison of a straw/concentrate mixture with silage as a buffer feed for grazing dairy cows |
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| Authors: | D J ROBERTS E F KELLY† |
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| Institution: | West of Scotland College, Crichton Royal Farm, Dumfries, UK |
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| Abstract: | Over a 24-week period during the 1986 summer, three groups of January- to March-calving dairy cows were either grazed conventionally (G) or grazed between morning and afternoon milkings and housed overnight and offered grass silage (Si) or a straw/concentrate mixture (St) ad libitum. The straw/concentrate mixture contained proportionately, 0-33 long barley straw, 0·28 ground barley, 0·12 soya bean meal, 0·25 molaferm and 0·22 minerals. The metabolizable energy (ME) and crude protein (CP) contents of the silage fed in weeks 1-8 and weeks 9-24 were 9-5 and 10?6 MJ kg MD?1 and 160 and 191 g kg DM?1 respectively. The straw mix had an ME content of 10?1 MJ kg DM?1 and CP content of 134 g kg DM?1. Partial storage feeding with silage or a straw/concentrate mixture led to a decrease in estimated herbage DM intake. The feeding of the straw/concentrate mixture increased total DM intake, but the estimated total ME intake was similar for treatments G and St. The intakes (kg DM d?1) for treatments G, Si and St were respectively, herbage 11·7,6·8,4·1; total l3·5,13·6,15·0; total ME intake (MJd?1) 163, 155, 163.
Animal performance was, for treatments G, Si and St respectively: milk yield (kg d?1) 19·2, 17·5, 19·1 (s.e.d. 0-87); milk fat content (g kg?1) 36·9, 37·6, 37.1 (s.e.d. 1.22); milk protein content (g kg?1) 35·3, 32·9, 33·4 (s.e.d. 0·76). |
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