COMPOSITION OF WEIGHT CHANGE IN THE PREGNANT EWE

Abstract

Mature ewes were allotted to 10 groups of 11 each. The groups were subdivided into four pairs, each of one pregnant (P) and one nonpregnant (NP) ewe, plus three ewes to provide initial slaughter data (I). One pair from each group was slaughtered 35, 75, 105, and 140 days after the P ewe was bred. Both P and NP ewes received a submaintenance feed allowance based on body weight. Relative to the I group, NP ewes lost weight during the first 10 wk and then tended to plateau, whereas P ewes gained weight from about wk 5. Initially, the gain of P ewes equated with weight of concepta, but by day 140 weight of concepta exceeded total gain, indicating maternal loss during the final 35 days. Pregnant ewes had significantly (P < 0.05) more fat than did NP ewes at day 35, whereas at subsequent stages there were no significant differences, although there was a tendency for P ewes to have less fat than NP ewes by day 140. In energy terms, P ewes appeared to lose about 11% more from the body than did NP ewes.