Abstract

The Awassi is a fat-tailed sheep breed from the Middle East that has recently been imported into New Zealand for live-sheep export and for milk production. The aim of the current trial was to compare the carcass and meat quality of Awassi-cross and Texel-cross ram lambs. There were 36 lambs in each sire-breed group with an equal number from Romney and Poll Dorset ewes. Lambs were allocated at random within breed-cross groups to groups of 9 that were slaughtered in either May or August to give an overall mean carcass weight of 19.7kg. The Awassi-sired group had a lower dressing-out percent (44.4 vs 44.8; P<0.01), similar GR tissue depths (7.6 vs 8.4 mm) but more weight-adjusted leg fat (537 vs 446g. P<0.001). The most clear-cut difference was in carcass shape with Awassi-cross lambs having longer carcasses (1068 vs 1013 mm), longer legs, and longer, heavier leg bones at a constant carcass weight (all P<0.001). The shape difference at a common carcass weight was also reflected in the Awassi-cross lambs having lower leg muscle to bone ratios (3.49 vs 3.88), muscle weight (2047 vs 2172 g), and muscularity values (0.436 vs 0.488) than the Texel-cross lambs, and shallower longissimus muscle depths (28.0 vs 29.8 mm)(all P<0.01). Differences between Awassi and Texel-sired lambs in tenderness (shear values) and colour (L*,a*,B* values) of the semimembranosus muscle were not significant. Differences between dam-breed groups were generally small, although, relative to the Poll Dorset, the Romney-cross group had lower weight-adjusted longissimus depths (28.2 vs 29.6 mm) and leg muscle to bone ratios (3.57 vs 3.80(both P<0.01). When adjusted to the same carcass weight, lambs slaughtered in August had lower dressing-out percentages (42.6 vs 46.6), lower GR depths (6.7 vs 9.3 mm, longer carcasses (1063 vs 1018 mm), and poorer leg muscularity (0.450 vs 0.474) than those slaughtered in May (all P<0.02). In this study Awassi-cross carcasses were inferior to those of Texel-cross lambs in terms of composition and shape, but differences in meat quality not apparent.

IJ, Holloway, RW Purchas, MT Power, and NA Thomson

Proceedings of the New Zealand Society of Animal Production, Volume 54, , 209-214, 1994