No abstract

MATT'N, P., ADELAK''w, V. eNo Duroun, J. lgg7. Corpus

AorrexouN, V., MATroN, P. eNo Dupoun, J. J. 1978. Steroid

Twenty-nine DLS (l/2 Dorset, 1/4 Leicester, 1/4 Suffolk) ewes selected for extended breeding season, were involved in this study which lasted for 18 mo. According to their lambing date relative to January first, 15 ewes had a high lambing index whereas the others had a low index, the difference being 33 days (P<0.01). Half the ewes were assigned at random to remain nonpregnant throughout the study, whereas the other half was mated in July and August. From I May to 15 July, 20 ewes (69%') were cycling of which 817o were from the high and 54Vo from the low index group (0.05>P<0.10). Two ewes (7Va)

Plasma steroids (cortisol, progesterone, estrone and estradiol) were studied during the peripartum period in cows with three different types of parturition: unifoetal normal (VUN), unifoetal with retained placenta (VRP), multifoetal with or without retained placenta (VG). In the control group, cortisol rose gradually from 8 ng/ml on day -7 to 1 1 ng/ml on the day of parturition and thereafter came back to the level of day -7. In the VRP group, cortisol was slightly lower than in the control on day -1 and it did not vary significantly before or after parturition. In the group of cows with multiple births, where retained placenta was encountered in 3/a cases, cortisol was much higher than in control animals. Plasma progesterone decreased gradually from 5.5 ng/ml to less than I ng/ml on the day of parturition in the control group. In the group VRP and VG, it was significantly higher than in the control on the 2 days before and on the day of parturition. The patterns of estrone and estradiol were similar in the groups VUN and VRP until the first day following parturition, but much higher in the cows giving birth to twins. During the postpartum period, the drop in estrogens was much slower in the VRP and VG groups than in the VUN control group. These results suggest that Can.