אסיף מאגר המחקר החקלאי

Two methods of inducing low plasma progesterone concentrations have different effects on dominant follicles in cows

Year:

2000

Source of publication :

Authors :

Volume :

83

Co-Authors:

Shaham-Albalancy, A., Department of Animal Science, Faculty of Agriculture, Hebrew University, Rehovot 76100, Israel
Rosenberg, M., Institute of Animal Science, Agricultural Research Organization, Bet Dagan 50250, Israel
Folman, Y., Institute of Animal Science, Agricultural Research Organization, Bet Dagan 50250, Israel
Graber, Y., Department of Animal Science, Faculty of Agriculture, Hebrew University, Rehovot 76100, Israel
Meidan, R., Department of Animal Science, Faculty of Agriculture, Hebrew University, Rehovot 76100, Israel
Wolfenson, D., Department of Animal Science, Faculty of Agriculture, Hebrew University, Rehovot 76100, Israel

Facilitators :

Link :

Abstract:

The effects of two methods of inducing low progesterone concentrations on the shape of the plasma progesterone curve and on follicular characteristics in lactating cows were studied. A low ascending progesterone curve was elicited by three PGF2α injections on d 3 to 4 of the estrous cycle; a low constant curve by induction of corpus luteum regression on d 6 and insertion of two progesterone-containing intravaginal devices from d 6 to 15 of the cycle. Plasma progesterone concentration was highest in the untreated control group, intermediate in low ascending group, and lowest in the low constant group. On d 15, both control and low ascending groups had one large healthy and one large atretic follicle, suggesting a turnover of follicular waves; in the low constant group, the presence of only one very large healthy follicle indicated follicular persistence. Estradiol concentration in the follicular fluid and its production by granulosa cells were highest in the low constant, intermediate in the low ascending, and lowest in the control group. Androstenedione concentration in the follicular fluid and its production by theca cells were higher in the low constant than in the low ascending and control groups. The results indicate that the low ascending progesterone curve affected follicular development and steroidogenesis differently from the low constant curve. We suggest that the low ascending curve mimics the effects of naturally occurring low plasma progesterone concentrations better, and it might, therefore, be used as a model for studying the effects of low plasma progesterone on fertility.

Note:

Related Files :

תוכן קשור

More details

You may also be interested in