Some sources of variation in tenderness and cooking losses in lamb and mutton

Abstract

Six experiments are reported involving 218 Southdown-Romney cross ewe and wether lambs slaughtered at either 15 weeks or 9 months of age, and 136 Romney wethers slaughtered at 16 months of age. The tenderness of the meat of these animals was assessed with a mechanical tenderometer on duplicate samples of the cooked longissimus dorsi muscle of the left side.Differences in tenderness attributable to sire and pasture type were considered. Although sire effects were not consistently significant, the moderately repeatable ranking of sire groups in two consecutive years suggests that selection for tenderness in sheep would be effective. Pasture effects, however, were neither significant nor repeatable.All experiments were characterised by the large proportion of residual variation (83%. 98%. and 72% in Experiments I. 2. and 3. for example) after a number of correction factors had been applied. This was attributed mainly to variations between animals in the way in which they reacted to treatment immediately before and lor after slaughter and to interactions between these treatments and the sources of variation that were considered.The relationship between fatness and cooking losses was examined and it was shown that the greater total cooking loss with increased fatness was due almost entirely to increased loss of drippings.

The tenderness of meat of several breeds of cattle raised under New Zealand pastoral conditions

“…Thus Purchas et al (1969) have reported a significant correlation between slaughter sequence and meat tenderness in lambs, and sarcomere length as a measure of the degree of muscle contraction can Everitt (1972) .…”