ABSTRACT
Distribution of fat, muscle and bone tissues was studied in bucks, wethers and doe Jebel Akhdar (JA) Omani goats raised under intensive management and slaughtered at 11, 18 or 28 kg body weight (BW). Weight of individual tissues was expressed as percentage of total respective tissue weight in the half carcass. Weight of total body fat in the empty body weight (EBW) ranged between 7.6% in bucks at 11 kg BW and 23.5% in does at 28 kg BW. At 18 kg BW, JA goats had higher TBF, carcass and non-carcass fat than those slaughtered at 12 kg BW (P<0.001). Does and wethers had a faster rate of deposition of carcass and non-carcass fat relative to EBW. Therefore, they had higher fat content (P<0.001) than bucks at 28 kg BW. The highest proportion of fat in the body was deposited intermusculary whereas the omentum constituted the highest non-carcass fat proportion. About 55% of the musculature in JA goat carcasses was found in muscle groups of the proximal hind leg, around the vertebral column and in the proximal forelimb (expensive muscle groups). Bucks had higher proportions of musculature in the forequarter (P<0.001) and intrinsic muscles of the neck but lower proportions of muscles at the proximal hind limb (P<0.001) than does and wethers. About 51% of the total skeleton was found in the axial skeleton, 22-23% in the forelimb and 22-23% in the hind limb of JA goats. There were few sex or slaughter weight effects on proportions of bone weight in the skeleton. In general, slaughter weight and sex effects on tissue distribution were more pronounced in the fat tissue. The magnitude of these effects on muscle and bone tissues was small and is unlikely to have economic impact on meat production from goats.
ABSTRACT
There is a history of copper deficiency in grazing Omani livestock and the copper status of three economically important goat breeds, Jabal Akhdar (JA), Batina (B) and Dhofari (D) were therefore compared in October/November (cool season) and June (dry season) in a penned flock given a plentiful dietary supply of copper. In the cool season, 62 lactating does (5 JA, 12 B and 33 D), their 0-5-day-old kids (17 JA, 19 B and 22 D) and 25 dry does (17 JA, 5 B and 3 D) were blood sampled. In the dry season, the does sampled were either barren (15 JA, 16 B and 13 D) or pregnant (9 JA, 13 B and 33 D). The samples were analysed for total copper (TCu) and trichloroacetic acid (TCA)-soluble copper (TCA-sol Cu). There were no effects of breed on TCu or TCA-sol Cu in the cool season, the overall means being 0.75 (SE 0.049) and 0.59 (SE 0.052) mg/L. The mean TCu was low in kids at birth (0.59 mg/L) but had increased to 0.86 mg/L by 4 days of age (p < 0.001); breed differences were found (p < 0.002), the pooled values for JA, B and D being 0.77, 0.59 and 0.68 (SE 0.033-0.044) mg/L, respectively. By the dry season, the mean TCu had risen in barren does to 0.96 (0.045) mg/L but not in pregnant does (0.76 (0.047) mg/L: p < 0.002) and breed differences had emerged, the mean for D being 20% lower than those for JA and B (p < 0.05). The highest TCu values were found in the 7-month-old kids in June ( 1.17 (0.039) mg/L) but the breeds did not then differ. Some effects on TCA solubility were found but were considered unreliable. Breed effects may have been diminished by the generous supply of copper and early stage of lactation studied.
