and Nutrition
PRACTICAL FEED-FLOW PROGRAMMES
Due to the nature of ostrich farming, various feed-flow programme approaches are encountered (e.g. Table 5.10) and husbandry practices vary from intensive zero-grazing systems to extensive farming on pastures or in arid areas (Verwoerd
et al., Chapter 8). Choice of diets is determined by: (i) stage of marketing; (ii)
final aim in slaughter or breeder birds; (iii) slaughter age; (iv) purpose of slaugh- ter bird, i.e. for meat, feather or hide production; (v) availability of ingredients, pastures and silage; and (vi) economy. The majority of birds in South Africa are slaughtered at 14 months of age with a mature feather plucking. Ideal body size for leather production is 95 kg, and any gain above this results in unnecessary deposition of fat for which farmers are occasionally penalized. Furthermore, no additional money is paid for hides exceeding 145 dm3 which corresponds to a
body mass of 95 kg. With recent changes in the ostrich market (Deeming, Chapter 1), there has been a rapid change to a younger slaughter age (8–10 months) as a result of changed demand for the type of product. This will allow a substantial saving in production costs due a reduction in feed requirements because the post-finisher diet will be omitted.
CONCLUSIONS
The ostrich is well adapted to its natural diet of vegetation, and because of post- gastric microbial fermentation it is very efficient at extracting nutrients and energy. Our understanding of ostrich nutrition for farmed birds is, by contrast, still in its infancy. Considerable further research is needed to validate require- ment information for major dietary components, and there is an urgent need to establish vitamin and mineral requirements for different ages. In light of work on fatty acid profiles of ostrich egg yolks by Noble et al. (1996), basic information on nutrient requirements of breeders is needed. A large and focused study on the effect of age on hide quality is lacking at this time.
As the industry focuses on production feeding, guidelines will have to be developed for each specific end point. Development of cost-effective feeding methods in different areas of the world will have to be a primary focus of research if this industry is to survive in the long term. As genetic improvements generate an ostrich with greater growth capacity and better feed conversion potential, nutrient requirements will change and thus feeding guidelines will need to follow.
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Reproduction
J.T. Soley and H.B. Groenewald
Department of Anatomy, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
The increasing demand for ostrich products experienced in recent years and the resultant pressure on breeders for accelerated production have focused attention on the reported low productivity in the industry (Table 7.1). Reports on the extent of the problem vary and although certain individual operations claim high fertility and hatchability rates, the industry in general is beset by a poor repro- ductive performance. This aspect is described in more detail by Deeming and Ar (Chapter 7).
Whereas intensive studies on the reproductive system of domestic poultry have been carried out and reported on in the literature, very little information is currently available on reproduction in ostriches. Many basic questions remain unanswered and certain avenues of research are hampered by a lack of elemen- tary data, particularly with respect to female reproduction. Here the current understanding of reproductive biology is reviewed with the exception of behav- iour which is described by Deeming and Bubier (Chapter 4).