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Viljoen M.,Cape Institute for Agricultural Training | Viljoen M.,University of Pretoria | Brand T.S.,University of Pretoria | Brand T.S.,Elsenburg Animal Production Institute | And 3 more authors.
Poultry Science | Year: 2012

This study was performed to obtain information on yolk utilization in fasted and fed ostrich chicks posthatching. The fasted trial lasted for 7 d, whereas the fed trial continued for 16 d. Fasted ostrich chicks showed a decrease of 31.3 g of BW, with yolk weight decreasing by 28.9 g daily after hatching. Yolk weight comprised 28% of 1-d-old ostrich chick BW and decreased to 12% at 7 d of age. Only 44.4% of the fasted ostrich chick yolk was assimilated over the trial period. Crude protein content of the yolk decreased by 13.2 g daily. Fat content increased by 1.77% daily, whereas total yolk fat weight decreased with 8.91 g daily. Slaughter weight of fed ostrich chicks increased, with yolk weight decreasing by 16.3 g daily. Yolk content for fed ostrich chicks was 26% of BW at 2 d of age. Ostrich chicks absorb 30% of yolk over the first 4 d, 67% after 8 d, and only deplete the yolk after 14 d posthatch. Fasted ostrich chicks absorbed the yolk content at a rate of 28.9 g/d, compared with 22.3 g/d over the first 8 d and 16.3 g/d over the 16 d for fed ostrich chicks. The CP content of the yolk decreased by 6.84 g daily in fed ostrich chicks, whereas fat content of the yolk increased by 1.39% daily, although total yolk fat weight decreased by 6.61 g daily. Yolk weight and total CP decreased faster over the first 7 d in the fasted ostrich chicks compared with the fed ostrich chicks, which indicated that the decrease in yolk weight could be attributed to absorption of protein from the yolk. Fat content decreased faster over the first 8 d from the yolk of the fed ostrich chicks compared with that from the yolk of the fasted ostrich chicks, which could indicate that external feed has a positive influence on the absorption of fat from the yolk content. © 2012 Poultry Science Association Inc.

Brand T.S.,Elsenburg Animal Production Institute | Brand T.S.,Stellenbosch University | Tesselaar G.A.,Stellenbosch University | Hoffman L.C.,Stellenbosch University | Brand Z.,Elsenburg Animal Production Institute
British Poultry Science | Year: 2015

Abstract: South Africa currently produces 70% of the world’s ostrich products. The profit margin of South African producers from the sale of ostrich meat, leather and feathers currently stands at 20%, 65% and 15%, respectively. Local producers want to increase the production of ostrich products but keep production costs as low as possible. Maintaining optimal nutrition of breeding stock is necessary to increase the production of ostrich chicks, thereby decreasing the fixed costs per chick. This research examined the impact on ostrich reproduction of replacing soya oilcake (SOC) as a protein supplement with cheaper cottonseed oilcake (CSOC). Although there are no data available on the impact of CSOC feed on ostrich reproduction, it is well known that gossypol, a naturally occurring toxin in cotton plants, negatively affects male reproduction in other monogastric species and that it may also reduce appetite. Ninety-six breeding ostrich pairs were divided into two groups to compare the effects of diet (CSOC and SOC) during the breeding season on ostrich-breeding parameters. The replacement of SOC with CSOC had no significant effect on the number of total eggs produced (47.8 ± 5.3 versus 48.3 ± 5.1 per breeding pair, respectively) or infertile eggs (31.5 ± 3.9 versus 38.0 ± 5.2, respectively). Also, the number of dead-in-shell chicks did not differ significantly between groups (20.2 ± 3.3 versus 26.8 ± 3.8, respectively). Even though none of these breeding parameters differed, the replacement of SOC with CSOC in the diets of breeding birds led to significantly more chicks hatching per hen from breeding birds fed on the SOC (36.1 ± 4.8) than the CSOC diet (17.2 ± 3.8). Although it would thus seem that feeding breeding ostriches CSOC instead of SOC as a protein supplement will have a detrimental effect on chick production, more data are required to deliver a definitive answer. © 2015 British Poultry Science Ltd.

van der Westhuizen E.J.,Stellenbosch University | Brand T.S.,Stellenbosch University | Brand T.S.,Elsenburg Animal Production Institute | Hoffman L.C.,Stellenbosch University | Aucamp B.B.,Elsenburg Animal Production Institute
South African Journal of Animal Sciences | Year: 2010

The goal of this study was to determine the effect of gender on visceral and subcutaneous fat distribution of Merino lambs finished off under feedlot conditions. The diet (16% protein, 10MJ ME/kg feed) was fed ad libitum and animals had free access to water. A total of 108 lambs (58 wethers, 50 ewes) were divided into six groups. Groups of lambs were slaughtered every three weeks at respectively 90, 111, 132, 153, 174 and 195 days of age. The visceral fat was removed, weighed and expressed as a percentage of carcass mass, while the subcutaneous fat thickness was measured at the 13th rib. A growth curve was calculated for each gender, and the effect of age on the different fat parameters determined. The growth rates of male and female lambs did not differ and were respectively 45.2 g and 43.2 g per day. Age had a positive effect on % visceral fat with an increase of 0.029% for wethers and 0.032% for ewes per day. Similarly, fat thickness increased at a rate of 0.070 mm for wethers and 0.053 mm for ewes per day, indicating that gender had an influence on the rate of fat deposition. However, the inverse rate of deposition between the genders (visceral fat versus subcutaneous fat) warrants further discussion. © South African Society for Animal Science.

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