INFLUENCE OF THE NUMBER OF SUCKLING YOUNG AND THE FEED LEVEL ON FETALSURVIVAL AND GROWTH IN RABBIT DOES

This study was undertaken to determine the influence of various degree s of nutritional deficit on foetal survival and growth in pregnant and lactating does. All females were mated within 12 h of parturition (d 0) and slaughtered at d 28. For around half of them, lactation was ter minated at parturition and does were fed ad libitum throughout gestati on (CNL group, n = 28) or feeding was restricted from d 15-28 (RNL gro up, n = 27). Other females were allowed to nurse 4 (FL group, n = 27) or 10 young (TL group, n = 27), and were fed ad libitum. Live-weight v ariation between d 14 and 28 (deltap1428) varied highly between groups (CNL: +194 g; RNL: +112 g; FL: -1 13 g; TL: -1 97 g; P < 0.01). Late foetal mortality (> d 15) was significantly increased in lactating gro ups (FL: 10.4%, TL: 15.5%) compared with non-lactating groups (CNL: 5. 4%; RNL: 3.6%) without any influence of deltap1428. The weight of the foetuses was significantly lower in the lactating groups (CNL: 39.7 g; RNL: 39.3 g; FL: 37.5 g; TL: 34.9 g; P < 0.001) and was negatively re lated to deltap1428 (r = 0.47; P < 0.001). The concentrations of proge sterone were lower in lactating than in non-lactating does (TL + FL vs CNL + RNL; P < 0.01) on d 7 and 17, but similar on d 28. These result s suggest that the detrimental effect of lactation on foetal survival and growth can be decreased by reducing the number of suckling young.