Day 0 Protocol: Superstimulatory treatment initiated in the absence of a large follicle improves ovarian response and embryo yield in goats

A new superstimulatory protocol (Day 0 Protocol) to initiate FSH treatment in the absence of a large follicle was compared to a traditional protocol in goats. The Day 0 Protocol (n = 44) consisted of pre-treatment with progesterone and eCG to synchronize ovulation and the emergence of Wave 1, with FSH starting 84 h after the end of progesterone exposure (i.e., soon after ovulation). The traditional protocol (n = 46) consisted of 11 d of progesterone exposure, with FSH treatment beginning 2 d before the end of progesterone exposure. Treatment with FSH was initiated in the absence of a large follicle in 37/44 and in 6/46 goats in the Day 0 Protocol and traditional protocol, respectively (P < 0.01). There was more CL in the Day 0 Protocol than in the traditional protocol (breeding season: 9.6 ± 0.6 and 6.3 ± 0.8, P < 0.05; non-breeding season: 14.3 ± 1.5 and 10.7 ± 1.5; P < 0.05). More Grades 1 and 2 embryos were recovered in the Day 0 Protocol than in the traditional protocol (breeding season: 4.8 ± 0.7 and 1.8 ± 0.5, P < 0.05; non-breeding season: 5.6 ± 1.1 and 3.5 ± 0.7, P = 0.07). Similarly, the proportion of embryos that were Grades 1 and 2 was higher for the Day 0 Protocol than for the traditional protocol (breeding season: 81/114, 71%, versus 16/43, 37%, P < 0.05; non-breeding season: 118/203, 58% versus 95/205, 46%, P < 0.05). In summary, the Day 0 Protocol, was effective in initiating superstimulatory treatment in the absence of a large follicle, and compared to the traditional protocol, induced a higher ovulation rate and better embryo yield in goats.