The effect of weight stasis on the dissected carcass composition of crossbred sheep

Abstract

A study was made of the dissected carcass composition of crossbred wethers (progeny of Dorset Horn rams and Border Leicester x Merino ewes) maintained at 30 kg liveweight for either 0, 25, 50 or 75 days. Animals were individually penned and fed a pelleted ration of 80% lucerne chaff and 20% cereal grain (89.3% dry matter, I4.8To crude protein and 18.27 kJ/g gross energy). Cold carcass weight showed a significant increase (P < 0.05) in animals during weight stasis, although dry matter intake of animals during weight stasis decreased. All dissected carcass fat depots increased during weight srasis, although only subcutaneous fat showed a significant increase (P < 0.05) in weight. Neither the weight of total dissected side muscle nor total dissected side bone was affected by weight stasis. Only the weight of Standard muscle group 1 showed a significant response to weight stasis, and it increased (P < 0-05). Weight stasis had no effect on the weights of separate bones. Results for fat, muscle and bone distribution are reported. Subcutaneous fat formed a significantly increasing proportion of total side fat weight (P < 0.05) as duration of weight stasis increased, while intermuscular fat showed a trend to form a decreasing proportion. Weight stasis had no effect on the proportion of total side muscle formed by each of the Standard muscle groups, except group 4 which decreased (P < 0.05). Bone distribution was not influenced by weight stasis.