Effect of slaughter age and sex on the production output of South African Black ostriches.

1. The effects of different slaughter ages and sex on the yield and quality of economically important end-products of slaughtered ostriches was examined to determine the most economic slaughter age for growing/finishing ostriches. Two batches of 4- and 6-month-old ostriches were assigned to 10 treatment groups and fed ad libitum up to slaughter ages of 8·5, 10·5, 12·5, 14·5 and 16·5 months. Slaughter weight, cold carcase yield, skin surface area, dry skin grade, feather yield and feed intake of ostriches were measured for each age. 2. Cold carcase yields and total feather yields of males were higher than females but yields of other products were similar. 3. Slaughter weight, cold carcase yield, skin surface area, dry skin grade, feather yield and feed intake increased with age with significant differences between most age groups. Cold carcase weight increased by approximately 2·2 kg and skin surface area increased by 3·1 dm³ with each additional month of growth but the quality (grade) of skins and the proportion of first grade skins decreased with increasing age. This, together with an increase in feed intake associated with age to slaughtering should be taken into account when determining the optimal slaughter age. 4. The set of biological variables established in this study can be used to determine the most economical slaughter age under varying market conditions.