Economic optimum nutrition of growing pigs.
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Date
2022
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Abstract
In two trials, a total of 504 boars and 504 gilts were used to determine the most profitable
feeding strategy for the Topigs TN60 strain under current economic circumstances, using margin
over feed cost as the objective function. The trials started when the pigs were 10 weeks old and
were terminated after a 12-week trial period in each case. In the first trial the EFG Pig Model and
Optimiser was used to assess the current feeding strategy used on the Baynesfield Estate, and to
determine how the optimum strategy might change under different economic scenarios. An
added objective was to evaluate the Pig Growth Model by comparing the predictions made by the
model with the actual outcomes of the trial. Significant differences in gains, feed intake and
carcass parameters were measured across sexes and feed treatments, and hence margin over
feed cost, under the different economic scenarios applied. The Growth Model accurately predicted
the optimum feeding strategy although the predicted feed intakes were marginally lower than
those measured in the trial.
The response to a series of feeds differing in balanced protein was measured in the second trial,
the main objective being to develop equations that would describe the response of boars and gilts
of this strain to dietary protein. These equations could then be used in the future to calculate the
optimum economic level of dietary protein as economic circumstances on the farm changed. The
results of both the simulation exercise and the trial provided strong evidence that the optimum
economic level of dietary protein differs for gilts and boars, and that this difference widens as
profitability in the enterprise is reduced, either through an increase in the cost of feed ingredients
or when pork prices decline. Uniformity in body and carcass weight was increased with dietary
protein content. The results of both trials provide convincing evidence that gilts and boars should
be reared separately, and fed different dietary protein levels, if margin over feed cost is to be
maximized, and that the economic optimum feeding strategy is not static but varies with economic
circumstances.
Description
Masters Degree. University of KwaZulu-Natal, Pietermaritzburg.