Studies in Ruminant Nutrition

The work in this thesis investigates the use of a novel dried sugar beet pulp product manufactured by adding lime before compression to remove water before drying for use as a feed supplement for ruminant livestock. It also investigates the practical use of wheat dark distillers grains arising from fermentation of wheat. In Section 1, the nutrient content of the novel sugar beet pulp was evaluated. In experiment 1, the metabolisable energy was 11 MJ/Kg. DM and about 1 MJ less than for the other normal sugar beet pulp products. The digestible crude protein was determined to be 47g/kg DM, which was lower by about 10g/kg than for the other normal sugar beet products. The limed sugar beet pulp also contained higher levels of calcium and phospohorus than the normal sugar beet pulps. In experiment 2, the crude protein degradability in the rumen was found to be very similar to those of the other normal sugar beet pulp products, i.e. about 25% for the unmolassed and 60% for the molassed products. In experiment 3, the acceptability and palatability of the novel sugar beet product was assessed in trials involving ruminant livestock in different physiological states and ages. It was observed that intermixing of this product with other readily acceptable and palatable feed supplements could in general enhance palatability and hence intake. In Section 2, the nutritive value of the limed sugar beet product was assessed in production trials involving pregnant and lactating ewes and beef cows. In experiment 1, with lactating ewes given about 1 kg DM each of hay and concentrate supplement made up of about 60% sugar beet products and 40% wheat dark distillers grain and soya, the mean daily liveweight loss was about 0.26 kg over a three week trial period. The daily mean liveweight gain of their lambs over the same period was about 0.25 kg. In a comparative trial involving sets of twin and triplet lambs, individual twin lamb outgrew individual triplet lamb very significantly but the total daily liveweight gain of the triplets (570g) was greater than that for the twins (504g). In experiment 2 in which the variations in the probable colostrum intake on the growth performance of twin lambs was studied, the daily mean liveweight gain of males (0.27 kg) rather than females (0.25 kg) and for Texel was (0.28 kg) rather than Suffolk cross (0.26 kg) . In experiment 3, the daily mean liveweight loss to suckler cows given about 6 kg fresh hay and 3 kg fresh concentrate based on limed sugar beet pulp and wheat dark distillers grains daily was 0.19 kg and the daily mean liveweight gain of the suckler calves was 1.1 kg over the first six weeks of lactation. In section 3, the feeding of a novel wheat dark distillers grains as concentrate feed supplement to lactating dairy cows was compared with a high nutritional quality dairy concentrate compound feed devoid of distillers grain with respect to milk yield and milk fat and protein constituents. The wheat dark distillers grains compared favourably with the compound feed and it could replace the compound feed as a source of concentrate supplement to lactating dairy cows when substituted for 4 kg/day (fresh matter) at mean milk yield of about 9 l/day. It is concluded that limed sugar beet pulp could be fed as a concentrate feed supplement to productive ruminant livestock especially when incorporated with readily acceptable and palatable feeds with high crude-protein and phosphorus contents without any detrimental effect on the animals or their products. Similarly, supplementing the diet of lactating dairy cows with wheat dark distillers grains could economically replace a more expensive compound feed without loss of milk yield or reduction in quality