This question was recently received:
“So far I have been using standard growth curve of ostrich from the data of Cilliers and Van Schalkwyk, 1994. If you have any better standard ostrich growth curve, please let me know.”
We pointed the nutritionist in the direction of this paper “Potential Meat Yield of Ostrich”. The question emphasises the need to keep reinforcing the message that paper discussed as it is key to understanding what is required for the commercial success of ostrich production.
During the early and mid 1990s work was carried out by a few people to understand the growth curve of ostrich. When examining the evidence during the research for that paper, there is one paper of concern. The paper was presented at the 1996 European Ostrich Conference, co–written by a number of the scientists from Stellenbosch University entitled: “Nutrition of the Ostrich for Meat and Leather.” The reason for the concern is a discussion on reducing the potential rather than asking searching questions “if current production was not achieving that potential, what was required to achieve that potential”?
The aim in commercial livestock production is to enable the animal to achieve commercial slaughter weights as quickly as possible whilst maintaining optimum health and providing products the customer wants to buy. Of course it also necessary to achieve this at a price the consumer can afford and the farmer and processor can make a fair profit. The following graphic is taken from the paper "The Potential Meat Yield of Osrich".
The following are details of the different growth curves:
1. Gompertz A:
This is the abstract taken from a paper published in 1991 and available on line here:
"The Gompertz equation was used to compute growth curves for three groups of ostriches (Struthio camelus), from Oudtshoorn in South Africa, the Namib desert in Namibia and from Zimbabwe. All were reared under typical intensive farm conditions with ad libitum feeding. There were no significant differences in mature mass between regions but the maximum daily weight gain for males occurred later (day 163) for Oudtshoorn birds, compared with day 121 for Namibian and day 92 for Zimbabwean. Oudtshoorn females reached maximum rate of gain on day 175 compared with day 115 for Namibian and day 114 for Zimbabwean. Comparisons might prove important when planning programmes for the genetic improvement of commercial flocks, but possible influences of food composition and environment should be investigated."
At the 1996 European conference there was another paper that reported growth results from a trial carried out in Israel using turkey rations. When comparing these results one can see that they achieved improved growth rates over the reduced targets set by these scientists from Stellenbosch .
3. Blue Mountain Farmer Bench Mark Study
The full details of this study are available here.
When reviewing all data then available one has to include the Blue Mountain Farmer weight gain benchmark recordings. As a farmer the major aspect that set this data apart was the fact that the information was published monthly as the birds were recorded. It was presented in such a fashion that the outcome was clearly known; it was an exercise to simply record the data for other’s to see and carried out to enable farmers to have sound benchmark figures.
4. Gompertz B
The paper “Nutrition of the Ostrich for Meat and Leather” referenced above, suggested that the estimated growth rates as determined in 1991 may not be possible, so reduced the targets to the levels illustrated in this curve..
After plotting all the published date – the message they tell is compelling. One as to question just why one would downgrade that Gompertz A to a level lower than results published by birds fed on rations designed for a totally different species? Why did the scientists not ask the question “what is required to achieve the estimated potential of ostrich"?