Effects of clover in the diet of grazed lambs on production and carcass composition

Abstract

The effect of grazing clover on ewes and lambs was studied using nitrogen-fertilized grass (G) and grass/white clover pastures (GC) containing proportionately 0-18 clover. Carcasses of lambs grazed on GC were significantly heavier than carcasses of lambs grazed on G pastures. An interaction with weaning occurred. Carcasses from lambs grazed on GC for 53 days post weaning were 2-3 kg heavier (F < 0-01) but lambs slaughtered at weaning had similar carcass weights. Diet had no effect on relative joint components of carcasses. The effect of clover in the diet on carcass weight was attributed to higher levels of protein retention. Analysis of the fatty acid composition of intramuscular and subcutaneous and perirenal lipids indicated small but significant effects of diet. Lean tissue lipids of lambs grazing clover showed significant increases in C18:2 and reduced C20 : 5 fatty acids. In tissue fats there were small increases in C14 : 0, C16 : 0 and C18 : 2 with reduced C18:1 content. Twin suckled lambs grazing GC for 94 days from turn-out in early April showed increased live-weight gain over lambs on G of 336 v. 287 glday (s.e.d. 84; P < 0-001). Post weaning live-weight gain of lambs was 173 and 221 g/day on G and GC respectively. Sward height was maintained at 5-18 and 5-24 (s.e.d. 0-075) cm on G and GC paddocks by adjusting ewe numbers. GC pastures carried proportionately 0-82 of the stock on G pastures but output of lamb was similar at 1289 and 1247 kg/ha for G and GC respectively. Results shoioed that the production penalty of lower stocking rate associated with grass/clover v. grass fertilized with 190 kg nitrogen per ha was ameliorated by higher lamb live-weight gain and carcass weight without change in joint composition or nutritionally significant change in fatty acid composition of carcass tissues.

Effect of dietary fatty acids on incorporation of long chain polyunsaturated fatty acids and conjugated linoleic acid in lamb, beef and pork meat: a review

“…Including clover decreased the intramuscular content of EPA while the deposition of LA, LNA and ARA were significantly increased. Similar results were reported by Vipond et al (1993) finishing lambs on swards containing white clover compared to grass finished lambs.…”

Addition of white clover to orchardgrass pasture improves the performance of grazing lambs, but not herbage production

“…These values are much higher than those repeated in ryegrass/white clover swards in the UK (Hopkins 1986;Vipond et al 1993;Orr et al 1995). The increasing clover concentration offsets the decline in nutritive value observed in grass monocultures.…”

“…However, considering the stocking density and DM yield in this study, it is apparent that intake could not have been higher for the Kay/Huia pasture. Increased utilization of legumes by livestock compared with grasses of similar digestibility is demonstrated with both grazed (Beever et al 1986;Vipond et al 1993) and ensiled forages (Stewart and McCullough 1985;Wilman and Williams 1993). This result is due to better N utilization in the rumen (Beever et al 1986;Broderick 1995).…”

“…Dry matter (DM) yield is generally less from mixtures than from pure grass that has received fertilizer N (Stewart and McCullough 1985), but individual animal performance is superior from legumes than grasses due to increased DM intake and increased digestibility (Beever et al 1986;Broderick 1995). Vipond et al (1993) show lamb weight gains increasing from 287 to 336 g d -1 pre-weaning and from 173 to 221 g d -1 post-weaning when grazing perennial ryegrass/white clover swards rather than pure swards of perennial ryegrass. This weight gain is attributed to increased N retention in lambs grazing the grass/clover mixture.…”

Produção de gado de corte e de pastagem de aveia em sistema de integração lavoura-pecuária em presença e ausência de trevo e nitrogênio

“…Corroborando as hipóteses apontadas, Vipond et al (1993) relatam que pastagens de trevos com gramíneas contendo não mais de 20% (neste ensaio foi de 10,5%) de trevo, a produção animal total é semelhante a uma pastagem apenas de gramíneas que recebem de 150 a 180 kg de N/ha.…”