Abraham V Ferreira

The effects of region and gender on the fatty acid, amino acid, mineral, myoglobin and collagen contents of impala (Aepyceros melampus) meat

The effects of sex and region on the fatty acid profile, mineral contents, collagen and myoglobin contents of impala (Aepyceros melampus) meat were investigated. The study was conducted in the Limpopo Province of South Africa where impala were sampled from two separate regions. Female animals at Mara showed higher levels (P<0.05) of saturated (SFA), and mono-unsaturated fatty acids (MUFA) in their tissues than the male animals. The females at Musina also showed a tendency (P<0.10) towards higher levels of SFA and MUFA than the males. Males from both regions showed higher levels (P<0.05) of poly-unsaturated fat than the females. Myristic, palmitic and stearic acid made up the greatest proportion of the SFA component for the males and females from both regions. Oleic acid represented the largest component of the MUFA, with the Mara animals showing higher levels than the Musina animals. α-linoleic, γ-linoleic, and linolenic acid made up the largest proportions of the poly-unsaturated component for both of the regions. Neither region nor sex had any influence on the amino acid content of the meat. The male animals at Mara had lower (P<0.05) myoglobin contents than the females for that region. Region had no effect on the myoglobin content of the meat. No significant sex or regional differences were found in the hydroxyproline and collagen contents of the meat (P>0.05). Regional differences (P<0.05) were found in the amounts of phosphorous and calcium present in the meat. The male animals at Mara were found to have higher levels of zinc than the females.

Meat quality of Boar 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.

Meat quality of Boer goat kids and Mutton Merino lambs 2. Sensory meat evaluation

The meat palatability, water-holding capacity, colour and shear force values 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 given to the animals for either 28 or 56 days. Thereafter the animals were slaughtered, the meat cooked and presented to a trained sensory panel. Organoleptically, a difference between goat and lamb was noted. Each one had a specific species flavour, which was not influenced by energy level of the diet. BG meat was perceived to be stringier than that of the MM, but there was no significant difference in Warner-Bratzler shear force values. Tenderness declined with age in both species and there was also a tendency for goat meat to be less juicy than lamb. Chevon had a more pronounced after-taste than lamb. No objective difference could be distinguished between the colour of the cooked goat and lamb, but there was a tendency for fresh lamb to have a higher a*-value (redness) than goat. Although diet did not influence drip loss, drip loss increased with an increase in slaughter age. Only after 56 days did the m. semimembranosus of MM have a significantly higher drip loss than that of BG (LE:4.84 v. 3.43%; HE:4.72 v. 3.23%). In the m. semimembranosus of both species cooking loss increased with an increase in slaughter age. It can be concluded that goat meat compares favourably with lamb in terms of water-holding capacity, colour and shear force values. If goats are finished in the feedlot, it can be done on a LE diet, since diet does not influences any of the mentioned characteristics. This may render a direct economic advantage for BG feedlot finishing.

Water intake of Boer goats and Mutton merinos receiving either a low or high energy feedlot diet

Individual water consumption and intake per unit body mass gain of 16 castrated Boer goat (BG) kids and 16 South African Mutton merino (MM) wether lambs were investigated. Two pelleted diets (fed to eight animals per species) with either a low (8.9 MJ ME kg DM) or a high (10.9 MJ ME kg DM) metabolisable energy level were fed individually, ad libitum for 56 days. The BG had a 49% lower (P < 0.01) water intake per kilogram mass gain than the MM on both the high and low energy diets. Both species had a lower (P < 0.01) intake on the high than on the low energy diet. Furthermore, the BG had a daily water intake of only 171 ml kg compared to the 302 ml kg of the MM.