Influence of progesterone supplementation on foetal survival in concurrently pregnant and lactating does

Abstract

Summary &horbar; An experiment was conducted to assess the influence of progesterone levels on late foetal mortality (second half of gestation) in concurrently pregnant and lactating does. All the females were mated within 12 h of parturition (d 0), and slaughtered on d 28 to study reproductive performance and body composition. Females were allowed to lactate 10 young and received either 2 progesterone implants (group P, n = 29) or 2 empty implants (group C, n = 29) on d 7. The feed intake, the live-weight variations of females during gestation, the growth of suckling litters, as well as the foetal weight and body composition of the does at slaughter, were similar in both groups. The concentration of progesterone was higher in group P than in C on d 16 and 25 (P < 0.01 The ovulation rate and late foetal mortality were similar in both groups but the early mortality was lower (12.3 vs 21.2%; P < 0.05) and the total number of foetuses on d 28 (live + resorbed + dead) was higher (9.8 vs 8.7; P < 0.05) in group P. These results indicate that progesterone supplementation improves early foetal survival but cannot increase late foetal survival in concurrently pregnant and lactating does.

Follicular, Oocyte and Embryo Features Related to Metabolic Status in Primiparous Lactating does Fed with High-Fibre Rearing Diets

“…As a consequence, in this study, NEFA concentrations were higher at parturition than at day 11 pp in both nutritional groups; yet, serum leptin and protein concentrations were enhanced at day 11 pp in contrast to the results observed in cattle (Leroy et al. 2005) but in agreement with previous reports in rabbits (Fortun 1994). Consistently, we observed lower body lipid depot, energy and protein content at parturition time compared with day 11 pp .…”

Les effets de la lactation sur les performances de reproduction chez la lapine

“…Par ailleurs, la mamelle et l'utérus étant utilisateurs des mêmes nutriments, certains d'entre eux peuvent devenir limitants pour la croissance foetale. Enfin, l'étude de l'état corporel des lapines allaitantes au 28, jour de gestation montre que le poids des tissus adipeux dissécables (périrénal et interscapulaire) est beaucoup plus faible que chez les lapines gravides non allaitantes (-70 niveau observé chez des lapines non allaitantes ne modifie pas le poids des foetus ni la production laitière, estimée d'après la croissance des lapereaux allaités (Fortun 1994 Une supplémentation en prolactine chez des lapines gravides entraîne une diminution significative de l'ingestion spontanée d'aliment pendant la période de supplémentation (-26 %) qui est accompagnée d'une réduction du poids des foetus (-7,2 % ; Fortun et al 1994a). A l'inverse, les foetus sont significativement plus lourds chez les lapines dont le pic de prolactine qui suit la tétée a été supprimé par des injections de bromocriptine (+9,5 % ; Fortun et al 1994a).…”