Meat quality of Boer goat kids and Mutton Merino lambs 1. Commercial yields and chemical composition

Carcass measurements, commercial cuts and chemical composition of the meat of 32 Boer goat (BG) kids and 32 South African Mutton Merino (MM) lambs were investigated. Two pelleted diets (offered to 16 animals per species) with either a low (LE, 9.9 MJ/kg dry matter (DM)) or a high (HE, 12.1 MJ/kg DM) metabolizable energy level were offered, ad libitum, for either 28 or 56 days. Thereafter the animals were slaughtered and the carcasses dissected into South African commercial cuts. The 8-9-10-rib cut of each carcass was dissected and used for chemical analysis. MM had heavier carcasses (LE:19.87 v. 15.28 kg; HE:24.01 v. 17.05 kg), and proportionally heavier ribs and buttocks than BG and therefore one can expect higher prices for sheep carcasses than for those of goats. BG had significantly more moisture and protein and lower fat and energy values than MM. DM, fat and energy values increased with an increase in slaughter age in both species. BG had significantly higher concentrations of 11 of the 18 measured essential amino acids in their 8-9-10-rib cuts than the MM. Goat carcasses had higher Ca, K, Mg, Na and P levels than sheep carcasses, regardless of the diet offered. BG had a lower carcass cholesterol content than lamb (66.77 v. 99.28 mg/100g, respectively). Palmitic (C16:0), stearic (C18:0) and oleic (C18:1n9) acids comprised the greatest proportions of the fatty acids in the 8-9-10-rib cut. On both diets there was a significantly higher saturated to unsaturated (SFA:UFA) fatty acid ratio in lamb than in goat meat (LE:0.30 v. 0.845; HE 1.407 v. 0.892). It can be concluded that chemically the meat from young feedlot goats is not inferior to that of lamb, and since it has a higher protein percentage and lower fat, cholesterol and SFA it can be considered as a healthy food commodity. Since diet had little or no significant influence on the carcass weight distribution or chemical composition of the goats, BGs can be finished on a LE-diet in the feedlot. This may decrease the food cost significantly