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The nutrition of artificially reared lambs. 3. The effect of sex on the performance and carcass composition of lambs subjected to different nutritional treatments

Published online by Cambridge University Press:  02 September 2010

J. A. Morgan
Affiliation:
Department of Applied Biology, University of Cambridge
J. B. Owen
Affiliation:
Department of Applied Biology, University of Cambridge
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Summary

Forty-eight Suffolk cross lambs were reared artificially from 2 days of age. Sixteen entire males, 16 castrates (castrated by rubber ring at 2 days) and 16 female lambs were allocated at random to a set of 2×2×2 factorial treatments in which feeding was ad libitum or restricted for each of three growth periods—from 2 days old to 15 kg, from 15 to 25 kg and from 25 to 40 kg live weight.

The results showed no apparent interaction of sex and feeding treatment and differences due to sex were apparent only in the period after 25 kg live weight. Entire males grew faster and were more efficient at this stage although there was little difference in voluntary feed intake. Carcasses of the males were lower in fat and energy content and higher in protein content than those of females and castrates.

The feeding treatments in the main had similar effects to those shown in other studies in the series. Restricted milk feeding was compensated for by increased solid food consumption during the milk-feeding stage but in this experiment there was no tendency for restricted lambs to eat more and grow faster when fed ad libitum in the following period. Restricted feeding in the last period, particularly if preceded by restricted feeding, gave higher killing-out percentage, higher fat content and lower protein content in the carcass than feeding ad libitum. This finding was partly explained by the higher weight of the carcasses of the restricted lambs.

Type
Research Article
Copyright
Copyright © British Society of Animal Science 1973

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References

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