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Twenty-four multiparous Holstein-Friesian dairy cows were used in a replicated 4 x 4 Latin square changeover design experiment to test the effects of changing from ryegrass (Lolium perenne) silage to red clover (Trifolium pratense) silage in graded proportions on feed intakes, milk production, milk organoleptic qualities, and whole-body nitrogen partitioning. Four dietary treatments, comprising ad libitum access to 1 of 4 forage mixtures plus a standard allowance of 4 kg/d dairy concentrates, were offered. The 4 forage mixtures were, on a dry matter (DM) basis: 1) 100% grass silage, 2) 66% grass silage: 34% red clover silage, 3) 34% grass silage: 66% red clover silage, and 4) 100% red clover silage. In each of 4 experimental periods, there were 21 d for adaptation to diets and 7 d for measurements. There was an increase in both DM intakes and milk yields as the proportion of red clover in the diet increased. However, the increase in milk yield was not as great as the increase in DM intake, so that the efficiency of milk production, in terms of yield (kg) of milk per kg of DM intake, decreased. The concentrations of protein, milk fat, and the shorter chain saturated fatty acids decreased, whereas C18 polyunsaturated fatty acids (PUFA) and long-chain PUFA (C20+) increased as the proportion of red clover in the diet increased. There was little effect of dietary treatment on the organoleptic qualities of milk as assessed by taste panel analysis. There were no effects on the aroma of milk, on aftertaste, or overall liking of the milk. Milk was thicker and creamier in color when cows were fed grass silage compared with red clover silage. The flavor of milk was largely unaffected by dietary treatment. In conclusion, increasing the proportion of red clover in the diet of dairy cows increased feed intakes and milk yields, decreased the concentration of fat and protein in milk, increased PUFA for healthiness, and had little effect on milk organoleptic characteristics.

Management systems for finishing beef cattle, designed to meet environmental goals in the Less Favoured Areas (LFAs) of the UK, often rely on the integration of grazing of semi-natural pastures with sown permanent pasture. In this experiment, three management options were compared: (i) permanent pasture for grazing and silage production (treatment PP), (ii) permanent pasture for grazing and silage and grazing of Molinia-dominant semi-natural pasture in summer from June to August inclusively (treatment PP + SNP) and (iii) permanent pasture for grazing and silage and red clover (RC) silage for 0·25 of the silage requirement in winter (treatment PP + RC). The performance of spring-born Welsh Black steers was measured from turnout in spring 2002 until finishing in summer 2003. During summer 2002, the liveweight gain of steers grazing the semi-natural pasture was significantly lower than that of steers grazing the permanent pasture. There was a trend for the liveweight gains of the steers on the PP + SNP treatment to be higher from housing in autumn 2002, and live weights on all treatments were similar at the start of the red clover-feeding phase. Steers offered red clover silage had a significantly higher liveweight gains than those offered grass silage, but there was only a trend for a higher live weight at the end of the winter-feeding period. During summer 2003, liveweight gains were again higher on the permanent pasture. Finishing system significantly affected the fatty-acid profile of the meat produced, but there was no difference in the colour of meat in relation to shelf-life. Lipid oxidation was less for the meat from steers on the PP + SNP treatment than on the PP treatment, which, in turn, was less than for meat from the steers on the PP + RC treatment, and was in inverse proportion to the vitamin E concentration in the loin muscle. There were no significant differences in sensory panel scores for texture, juiciness or flavour of the meat. [ABSTRACT FROM AUTHOR]

Simmental x Holstein-Friesian steers were offered four forage diets. These comprised grass silage (G);proportionately 0.67 grass silage, proportionately 0 .33 maize silage (GGM); 0.33 grass silage, 0.67 maize silage (MMG); maize silage (M) from 424 (s.d. = 11.5)kg to slaughter at a minimum weight of 560 kg. Forages were mixed and offered ad libitum. Steers were offered 2 kg of a concentrate daily, the concentrate being formulated such that all steers had similar crude protein intakes across dietary treatments. A sample of steers was slaughtered at the beginning of the experimental period to allow the calculation of the rate of gain of the carcass and its components. Carcass dissection of a sample of steers allowed the development of a prediction equation of carcass composition based on thoracic limb dissection of all carcasses. Forage dry matter intake and live-weight gain increased linearly as maize silage replaced grass silage in the forage mixture, resulting in improvements in food conversion ratio (all P = 0.001). Killing-out proportion increased with maize silage inclusion (P < 0.001)but fat and conformation scores did not differ significantly between diets. However, increasing maize inclusion in the diet resulted in a greater weight (P = 0.05) and proportion (P = 0.008)of fat in the carcass, and significant increases in internal fat deposition. The inclusion of maize led to a progressive increase in the daily gains of carcass (P < 0.001), and significant increases in the daily gains of both fat (P < 0.001) and lean tissue (P < 0.001). Fat colour was more yellow in cattle given diets G and GGM than diets MMG and M (P < 0.001)and colour intensity was lower on diet M than the other three diets (P < 0.001).There were no significant differences in any aspects of eating quality between diets. Therefore, maize silage has the potential to reduce the time taken for finishing beef animals to achieve slaughter weight with no apparent detrimental effects on subsequent meat quality. [ABSTRACT FROM AUTHOR]