Alvarez RL, Ducoing WAE, Zarco QLA, Trujillo GAM

Language: English/Spanish
References: 26
Page: 25-31
PDF size: 88.64 Kb.

ABSTRACT

The purpose of this study was to establish the effect of estrous goats on the ovarian activity of their seasonally anestrous herdmates. Thirty adult female goats were studied during the anestrous season, and were randomly divided in three groups: Group I was formed with ten goats that were induced to estrous using melengestrol acetate (MGA) and pregnant mare serum gonadotrophine (PMSG); Group II included ten goats without any treatment but maintained in direct contact with the animals of Group I during the time of the experimental trial, and Group III, formed with ten goats that were untreated and mantained away of the other two groups. Estrous detection was carried out daily and blood samples for progesterone determination were taken twice per week in order to assess the occurrence of ovulation. Besides, blood samples for LH determination were taken in all the animals every two h from 36 to 72 h after the injection of PMSG to the animals in Group I. Ovulation was considered to have occurred when progesterone concentrations were increased above 1 ng/ml. All the goats in Group I ovulated after the hormonal treatment, whereas 80% of the goats in Group II and 40% of those in Group III ovulated during the following 13 days. The value in Group III was significantly lower (P‹0.05) than those in Groups I and II. Preovulatory peaks of LH were observed in Group I at 54.5 ? 9 h and in Group II at 64 ? 6 h after the end of the treatment of Group I. No peaks of LH were observed in Group III. Data obtained in this study indicate that goats in estrous are capable of inducing estrous, preovulatory peaks of LH and synchronized ovulation in seasonally anestrous goats. Thus, this is a real induction of ovarian activity and not a simple imitation of behaviour.

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