The Effect of Dietary Energy and Protein Levels During a Breeding Season of Ostriches (Struthio cemelus domesticus) on Production the Following Season.

In a study on ostrich nutrition that spanned three breeding seasons, we assessed the effect of different energy and protein levels in the previous breeding season on production in the following breeding season. During the first breeding season, groups of breeding ostriches were fed diets with energy levels of 8.5, 9.5 and 10.5 MJ metabolisable energy (ME)/kg dry matter (DM) and protein levels of 13.5, 15.0 and 16.5%. Amino acid profile was balanced and was related to the protein content in all cases. In the second breeding season, groups were fed diets with levels of 7.5, 8.5 and 9.5 MJ ME/kg DM and 10.5, 12.0 and 13.5% protein, and during the third breeding season all the breeding birds were fed a single diet of 9.5 MJ ME/kg DM and 12% protein. Different levels of dietary protein in previous years had no effect on egg production, egg weight, fertility, hatchability and initial chick weight in subsequent years of production. Different levels of dietary energy in previous years had no significant effect on the body weight of breeding females, initial egg weight or the percentage of infertile eggs produced over the three seasons, but females fed diets containing only 7.5 MJ ME/kg DM during the second year produced significantly fewer eggs in the third breeding season, resulting in fewer chicks being hatched. It was concluded that there are potential carry-over effects of dietary energy levels from one year to the next and that an energy level of less than 8.5 MJ ME/kg DM in the diet may have an adverse effect on egg production in breeding female ostriches in following breeding seasons.