Influence of progestagen treatment length and of PGF sub (2alpha) administration time on ovulatory response and reproductive performances in meat sheep
2001
Gambacorta, M. | Maiorano, G. | Filetti, F. | Manchisi, A. (Universita del Molise, Campobasso (Italy). Dipartimento di Scienze Animali, Vegetali e dell'Ambiente)
Ovulatory response and reproductive performances in 60 cyclic and dry Gentile di Puglia ewes, subjected to hormonal treatments of oestrus synchronization, was evaluated in relation to progestagen treatment length (FGA, 30 mg, in pessary) and time of prostaglandin administration [PGF sub (2a), 125 microng - cloprostenol]. Therefore, in early autumn the animals were divided into three groups, homogeneous for number, age and weight, corresponding to the following treatments: a) FGA (14 days) + PMSG (400 IU, at pessary removal); b) PGF sub (2a) (12 days before the beginning of the progestagen treatment) + FGA (7 days) + PMSG (400 IU, at 5th d); c) FGA (7 days) + PGF sub (2a) and PMSG (400 IU, at 5th d). All the ewes were mated naturally. The ovulation time and the rate were detected by laparoscopy, while the occurrence of oestrus was monitored with harnesses equipped rams. The onset of oestrus occurred earlier (P0,01) in b) and c) groups than in a). The ovulation time following treatment c) was earlier (P0,01) than that of a). The hormonal treatments did not affect significantly the ovulation rate and reproductive performances. However, prolificacy and fecundity were the most satisfactory in ewes of the group b). The combined treatment with a shorter progestagen phase provided an efficient alternative to the FGA+PMSG treatment for the synchronization of oestrus
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