Fraser, M. D., Speijers, M. H. M., Theobald, V. J., Fychan, A. R., Jones, R. (2004). Production performance and meat quality of grazing lambs finished on red clover, lucerne or perennial ryegrass swards. Grass and Forage Science, 59, (4), 345-356. Sponsorship: DEFRA / MLCThe combined benefits of a high crude protein concentration, and possible protein protection and growth-promoting properties, make forage legumes potentially attractive as a natural means of increasing liveweight gain and time to slaughter of lambs in lamb finishing systems. An experiment was conducted to compare the production performance and meat quality of grazing lambs finished on red clover (Trifolium pratense), lucerne (Medicago sativa) or perennial ryegrass (Lolium perenne) swards. Replicate (n = 2) swards of red clover, lucerne and perennial ryegrass were rotationally grazed by ten ram lambs and ten ewe lambs from weaning until selection for slaughter at UK fat class 3L. Lambs grazing the red clover sward had a significantly higher liveweight gain and required significantly fewer days to slaughter than lambs grazing the lucerne sward (305 g d?1 vs. 243 g d?1; 38 d vs. 50 d), which in turn had a higher liveweight gain and required fewer days to slaughter than lambs grazing the perennial ryegrass sward (184 g d?1; 66 d). Lambs grazing the red clover and lucerne swards had significantly higher herbage intakes than those grazing the perennial ryegrass sward (2?06, 1?72 and 1?16 kg DM d?1 respectively), but in vivo digestibility of herbage was similar. Lambs grazing the red clover and lucerne swards also had significantly higher serum urea concentrations than those grazing ryegrass (12?5, 11?1 and 6?2 mmol L?1 respectively). Killing-out percentage was significantly higher for lambs grazing the red clover sward than for lambs grazing the perennial ryegrass sward (48% vs. 46%). There were no significant effects of finishing system on meat flavour, but meat from lambs finished on the lucerne sward was oxidatively less stable than that from lambs finished on the perennial ryegrass sward. Grazing the forage legume swards significantly increased the proportion of linoleic and linolenic acid in muscle tissue, and therefore the proportion of unsaturated to saturated fatty acids (0?19, 0?16 and 0?12 for the red clover, lucerne and perennial ryegrass swards respectively). However, the n?6/n?3 ratio was significantly lower for the muscle of lambs grazing the perennial ryegrass sward compared with those grazing the forage legume swards (1?13, 1?08 and 0?98 for the red clover, lucerne and perennial ryegrass swards respectively). The results indicate that by grazing lambs on forage legume swards it is possible to increase individual lamb performance without compromising meat quality.Peer reviewe

Winters, A. L., Fychan, A. R., Jones, R. (2001). Effect of formic acid and a bacterial inoculant on the amino acid composition of grass silage and on animal performance. Grass and Forage Science, 56, (2), 181-192. Sponsorship: UK Ministry of Agriculture, Fisheries and FoodAn Italian ryegrass and hybrid ryegrass sward was harvested on 11 May 1994. The mean dry-matter (DM) content of the herbage was 197 g kg?1 fresh matter (FM), and mean nitrogen and water-soluble carbohydrate contents were 20 and 272 g kg?1 DM respectively. Approximately 72% of total nitrogen (TN) was in the form of protein-nitrogen. The herbage was treated with either no additive, formic acid (3?3 l t?1) (Add-F, BP) or inoculant (2?3 l t?1) (Live-system, Genus) and ensiled in 100 t silos. Changes in effluent composition with time showed that silage fermentation and protein breakdown were delayed by treatment with formic acid. Formic acid and inoculant treatments also inhibited amino acid catabolism during ensilage. All silages were well fermented at opening with pH values <4?0 and ammonia-N concentrations of ? 50 g kg?1 TN after 120 d ensilage. Treatment had an effect on protein breakdown as measured by free amino acid concentration, with values of 21?5, 18?2 and 13?2 mol kg?1 N at opening (191 d) for untreated, formic acid-treated and inoculated silages respectively. Amino acid catabolism occurred to the greatest extent in untreated silages with significant decreases in glutamic acid, lysine and arginine, and increases in gamma amino butyric acid and ornithine. The silages were offered ad libitum without concentrate supplementation to thirty-six Charolais beef steers for a period of 69 d (mean live weight 401 kg). Silage dry-matter intakes and liveweight gains were significantly (P <0?05) higher on the treated silages. Silage dry-matter intakes were 7?42, 8?41 and 8?23 kg d?1 (s.e.d. 0?27) with liveweight gains of 0?66, 0?94 and 0?89 kg d?1 (s.e.d. 0?058) for untreated, formic acid-treated and inoculated silage-fed cattle respectively. In conclusion, additives increased the intake of silage and liveweight gain by the beef steers, and it is suggested that this may be caused in part by the amino acid balance in these silages.Peer reviewe

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Fraser, M. D., Fychan, A. R., Jones, R. (2001). The effect of harvest date and inoculation on the yield, fermentation characteristics and feeding value of forage pea and field bean silages. Grass and Forage Science, 56, (3), 218-230. Sponsorship: MAFF/Milk Development CouncilTwo experiments describe the ensiling potential of whole-crop forage peas (Pisum sativum) and field beans (Vicia faba). In Experiment 1, forage peas (cv. Magnus) and field beans (cv. Mayo) were harvested at 10, 12 and 14 weeks after sowing, and ensiled in 10 kg mini-silos either untreated or treated with an inoculant (Lactobacillus plantarum). In terms of yield and ensiling potential, the optimum growth stage for harvesting forage peas occurred at 12 weeks of growth. In contrast, delaying the harvest of field beans until 14 weeks gave the highest yields of dry matter (DM) and crude protein (CP). Changes in crop maturity had little effect on the chemical composition of the fresh forages, but between-harvest date differences were observed in the DM, ammonia-N, CP, water-soluble carbohydrates (WSC), acid-detergent fibre (ADF), neutral-detergent fibre (NDF), lactic acid and volatile fatty acids (VFA) concentrations and pH of the corresponding silages. Fermentation was improved by applying an inoculant. In Experiment 2, forage peas and field beans were harvested at 14 weeks after sowing and ensiled as round-bale silage, either untreated or treated with an inoculant. The yields of the crops were similar, and the only difference in the chemical composition of the wilted forages was a higher CP concentration in the field beans. However, after the ensiling process was complete, the forage pea silages were found to have significantly higher DM, WSC, starch and butyric acid concentrations compared with the field bean silages, and lower ammonia-N, CP, ADF, acetic acid and lactic acid concentrations. Inoculation was found to increase the lactic acid concentration and reduce the pH and ammonia-N and acetic acid concentrations of the silages. Each of the silages produced in Experiment 2 was offered to six Suffolk crossbred wether lambs, aged 10 months. Voluntary DM intakes were similar on all treatments, despite the apparent digestibility of the forage pea silages being significantly higher than that of the field bean silages. Nitrogen retention was higher for lambs offered forage pea silage. Application of an inoculant was found to have a negative effect on the amount of N retained, indicating the necessity for more detailed investigations into proteolytic activity within these crops during the fermentation process.Peer reviewe

Fraser, M. D., Winters, A. L., Fychan, A. R., Davies, D. R., Jones, R. (2001). The effect of harvest date and inoculation on the yield, fermentation characteristics and feeding value of kale silage. ? Grass and Forage Science, 56, (2), 151-161. Sponsorship: UK Ministry of Agriculture, Fisheries and Food and the Milk Development Council.Using new harvesting and ensiling technologies, it is now possible to ensile kale (Brassica oleracea) successfully. However, there is little information available regarding the optimum time for harvest. The aim of this 2-year study was to compare the yield, fermentation characteristics and feeding value of kale harvested at different stages of growth, and ensiled with and without a bacterial inoculant. During Year 1 the crop was harvested after 15, 18 and 20 weeks of growth. The yield at each harvest was similar, but as the crop matured the crude protein (CP) concentration and buffering capacity decreased significantly, and there was a marked increase in the water-soluble carbohydrate (WSC) concentration. During Year 2 the crop was harvested at 14 and 17 weeks of growth. Again, the stage of maturity did not affect yield and, on this occasion, the chemical composition of the crop was unaffected by harvest date. However, the WSC and CP concentrations of the crop were lower in Year 2 than in Year 1, possibly as a result of differences in fertilizer regime. Each of the silages produced in Year 2 was offered to six Suffolk cross wether lambs, aged 10 months, to measure voluntary intake, in vivo digestibility and nitrogen retention. Neither harvesting date nor the use of an inoculant affected voluntary intake or nitrogen retention by the lambs. However, in vivo digestibility was higher in the kale silage harvested after 14 weeks of growth and when an inoculant was applied. The results obtained suggest that harvesting kale after 14 weeks of growth can produce highly digestible silage with a high CP concentration. Although delaying harvest until 18 weeks of growth will probably result in a decrease in the CP concentration of the crop, it should also lead to an increase in the WSC concentration of the crop, ensuring a more reliable fermentation.Peer reviewe