Effects of clover and milk in the diet of grazed lambs on meat quality

Abstract

AbstractThe eating quality of lambs slaughtered at weaning or 8 to 9 weeks later off pastures of diploid grass (D), tetraploid grass (T) and tetraploid grass/white clover (TC) was studied. Samples of lean from grilled chops and roasted leg joints were assessed by members of a group of 36 sensory panellists for texture by rating juiciness and tenderness on an eight-point scale. Lamb and abnormal flavour were assessed in lean and fat samples. Lean from lambs slaughtered off the mother at weaning was significantly more tender than from lambs slaughtered 8 to 9 weeks later (5·8v. 5·0, s.e.d. 0·18; P < 0·001). There was a tendency for lambs slaughtered off TC to be more juicy and tender. Lean from chops was significantly more juicy and tender and of superior flavour to lean from leg and overall acceptability was higher for chops. Acceptability of lamb slaughtered at weaning was higher than of lamb slaughtered 8 to 9 weeks later (5·3v. 4·9, s.e.d. 0·14; P < 0·001).In further studies a trained sensory panel of 12 judges formed a consensus flavour profile for 10 attributes of lean and five attributes of fat. Univariate analysis revealed only small differences between treatments. Multivariate statistical procedures however identified significant treatment effects that appeared favourable to the flavour of lamb slaughtered off the mother although only around a third of the variation was explained.Analysis of weight loss on cooking showed less wastage when lambs were slaughtered off the mother (0·209 v. 0·225, s.e.d. 0·0043; P < 0·001) and when grazed on grass/clover (TC)v.grass (D, T) (0·206v. 0·222, 0·223; s.e.d. 0·0053;P < 0·01). Weight loss on cooking was negatively correlated with texture and overall acceptability.The results obtained provide evidence for enhanced eating quality from production systems involving the sale of lambs off the mother. Incorporation of grazing of clover pastures into production systems showed some small benefits.