Browsing by Author "Brand, M. M."

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    Carcass and muscle yields of ostriches as influenced by genotype
    (South African Society for Animal Science, 2007) Hoffman, L. C.; Brand, M. M.; Muller, M.; Cloete, S. W. P. (Schalk Willem Petrus van der Merwe)
    ABSTRACT: Live, carcass, leg and muscle weight (kg) as well as dressing percentage were compared between South African Black (Struthio camelus var. domesticus) ostriches, purebred Zimbabwean Blue Neck (Struthio camelus australis) ostriches and the progeny of Zimbabwean Blue Neck males crossed with South African Black females, commercially slaughtered at 14 months of age. South African Black ostriches had the lowest live (84.9 kg) and carcass (43.3 kg) weights, compared to Zimbabwean Blue Necks (100.9 and 51.2 kg, respectively). In general, crossbred birds resembled Zimbabwean Blue Necks more closely for the quantitative meat traits. However, dressing percentage (51.1%) and yields of different carcass components (bone, leg) did not differ between genotypes. Six of the major muscles present in the ostrich leg (M. gastrocnemius, M. femorotibialis accessorius, M. iliotibialis cranialis, M. iliotibialis lateralis, M. iliofibularis and M. iliofemoralis) showed significant weight differences between genotypes, with South African Black ostriches yielding the lowest values.
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    The fatty acid composition of muscles and fat depots of ostriches as influenced genotype
    (South African Society for Animal Science, 2012) Hoffman, L. C.; Brand, M. M.; Cloete, S. W. P. (Schalk Willem Petrus van der Merwe); Muller, M.
    Three genotypes of ostrich (South African Black, Zimbabwean Blue Necks and crosses between Zimbabwean Blue Neck males x South African Black females) were used to investigate the influence of genotype on the fatty acid composition of the musculus gastrocnemius and musculus iliofibularis, and abdominal and breast fat depots. Total saturated fatty acids in both the m. gastrocnemius and m. iliofibularis were higher in crosses (36.4% and 35.9%) than in South African Black ostriches (32.9% and 30.4%), whereas mono-unsaturated fatty acids were highest in South African Black ostriches. Total polyunsaturated fatty acids in the m. gastrocnemius were lowest in South African Black ostriches (26.5%) compared with the Zimbabwean Blue Necks (33.2%). Neither the ratio of polyunsaturated to saturated (0.73 to 0.99) nor n-6 to n-3 (1.6 to 2.2) fatty acids were influenced by genotype, although the ratio of polyunsaturated to saturated fatty acids in Zimbabwean Blue Necks was higher in the m. gastrocnemius (0.99) than in the m. iliofibularis (0.73). Differences in individual fatty acids were prominent in the breast fat, and total saturated and mono-unsaturated fatty acids differed between genotypes in both breast and abdominal fat. Only the ratio of polyunsaturated to saturated fatty acids in the fat depots differed between South African Black (0.48) and Zimbabwean Blue Neck ostriches (0.42). The latter ratio was higher in the breast (0.50) than abdominal (0.42) fat in Zimbabwean Blue Necks. These results indicate that crossbreeding of different genotypes of ostriches reared under similar conditions does influence the overall fatty acid profiles of meat and fat.
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    Live weight and reproduction performance of Zimbabwean blue and South African black ostriches
    (South African Society for Animal Science, 2008) Cloete, S. W. P. (Schalk Willem Petrus van der Merwe); Brand, M. M.; Hoffman, L. C.; Muller, M.
    Data obtained from a pair-mated ostrich flock located at Oudtshoorn in South Africa were used to derive line differences for live weight and reproduction performance in sexually mature ostriches of the Zimbabwean Blue (ZB) and South African Black (SAB) strains during 2003 to 2006. At the commencement of breeding ZB breeding stock were, on average, between 9 and 13% heavier than SAB contemporaries. At the cessation of breeding the superiority of ZB birds was reduced to between 4 and 8%, expressed relative to SAB breeding stock. Live weight at the commencement of breeding was complicated by an interaction between sire line and year. The interaction resulted from no line differences between SAB and ZB males in 2003, contrasted to marked differences in subsequent years. Egg production was affected by dam line, but not by the line of the sire or the interaction between dam line and sire line. Egg production of SAB females was almost twice that of ZB contemporaries, at respectively 43.3 and 23.3 eggs per season. The number of infertile eggs was not affected by any of the independent variables considered. The number of shell deaths was affected by both sire line and dam line. Overall, SAB females sustained lower levels of shell deaths than ZB females, while the eggs produced by mates of SAB males had higher shell deaths than mates of ZB males. Chick production was affected by dam line; the effects of sire line and the dam line x sire line interaction being non significant. Overall, SAB females produced more than double the number of chicks produced by their ZB contemporaries, at respectively 23.1 and 10.6 chicks per season. Both egg production and chick production were affected by a dam line x year interaction. No dam line difference was observed during 2003, whereas SAB females clearly outperformed ZB females in subsequent years. Further studies on the ostrich bloodlines and their crosses are needed to devise a selection and crossbreeding strategy for improving production and profitability in the industry.