Progesterone profile response to exogenous FSH, PMSG or GNRH-PGF_(2#alpha#) in non-cycling buffalo cows and effect of FSH or PMSG on early pregnancy

摘要

Nineteen non-cycling buffalo cows with extended postpartum period were utilized to determine effects of FSH, PMSG or GnrRH- PGF_(2#alpha#) on ovarian activity, in non-cycling buffalo cows. The experiment was designed into 2 stages; in the first stage. 9 cows received 1000IU PMSG and 10 cows received 37.5IU FSH. The cows which did not respond to these treatments were reutilized in the second stage, in which a regimen of GnRH-PGF_2 was applied. Cows were visually observed for estrous behavior by the aid of an intact revile bull, and those which showed estrous were naturally mated twice on a 2h-interval after onset of estrus. Blood samples were collected via Jugular vein in the first stage, four blood samples were collected on a weekly interval before the hormone injection at days -28, -21, -14, -7 and 0, in addition to seven samples at days 3, 10, 13.20.27, 34 and 42 after treatment. In the second stage, blood samples were collected at days -26. 0. 3.8. 13.17, 21, 25 and 30 where 0 was the day of GnRH injection At the time of palpation before initiation of the treatment, embedded CLs were found in 3 and 4 cows in the PMSG and FSH treatment, respectively These 7 cows were diagnosed as having smooth ovaries. In the PMSG group. 2 cows revealed a possession of short-lived CL with P_4 level > lng/ml for about 15 days without showing estrous symptoms, l cow had elevated P_4 (>5ng/ml) for 42 days post-treatment without estrous behavior, 3 cows did not ovulate (P_4<0.1ng/ml) throughout the term of the experiment and 3 cows had elevated P_4 levels (>lng/ml) and diagnosed as pregnant. However, in the FSH group. 4 cows each had an embedded CL before treatment, 3 cows developed short-life CL, 2 cows did not ovulate (P_4<0.1 ng/ml) and 1 cow showed estrus, ovulated, bred and became pregnant. FSH increased pregnancy rate by 10% however, PMSG did not. Regardless of the type of hormonal treatment. P_4 concentrations were significantly (P<0.01) higher in pregnant than non pregnant cows. No differences (P>O. 10) in P_4 levels between cows with a CL existing before or after either hormone treatment.