Superovulation in goats during the second follicular wave, with or without exogenous progesterone

The objective of this study was to evaluate a protocol for superovulation in goats designed to use the animals’ endogenous progesterone production, compared to a common protocol that utilized exogenous progesterone. The numbers of non-ovulated follicles, ova ovulated, and ova collected for each protocol were compared. In addition, the effect on these parameters of the day of first FSH administration, relative to the second follicular wave was investigated in the endogenous progesterone group. Forty alpine goats were divided into two groups. The +CIDR group (n = 20) received PGF2α 7 days prior to CIDR® insertion (CIDR insertion = day 0). The CIDR® was inserted for 14 days, and during this period PGF2α was injected on day 7 and FSH given in 8 equal doses over 4 days, starting on day 12. For the −CIDR group (n = 20), estrus was checked daily after an initial dose of PGF2α to allotted females that were approximately 7 days (range: 6–9 days) from estrus, when the first dose of FSH was administered. FSH (8 equal doses over 4 days) was administered, and PGF2α given on the second day of FSH administration. In both groups GnRH was given approximately 15–17 h after the last dose of FSH and surgery to collect early ova was performed 27–30 h later, to evaluate the superovulatory response. No significant differences in the mean numbers of non-ovulated follicles (+CIDR: 5.4 ± 0.8, −CIDR: 5.6 ± 1.0) and ovulation points (+CIDR: 13.8 ± 1.0, −CIDR: 13.7 ± 1.4) per doe were observed, nor in the total number of ova collected per female (+CIDR: 9.6 ± 1.2, −CIDR: 9.3 ± 1.4). In addition, no relationship of these parameters with the day of initial FSH administration in the −CIDR group was found. In conclusion, it was shown that if the time of estrus can be identified, superovulation can be reliably produced in goats, without the need for an exogenous source of progesterone.