Abstract :
Twenty-four Boer goat does were used to compare three superovulation protocols, with 8
does allocated per treatment during the natural breeding season. In Group 1 (Day 0 protocol),
the oestrous cycles of does were synchronised for 7 days with CIDR’s and injected
PGF2 at CIDR insertion. Does were then superovulated with pFSH in 7 dosages at 12 h
intervals, starting 88 h following CIDR removal. Concurrently with the 6th dosage, does
were injected PGF2 . Cervical inseminations were performed 24 h and 36 h following the
last superovulatory treatment. For Groups 2 and 3, the oestrous cycles of the does were
also synchronised for 17 days using CIDR’s. On day 14 of CIDR insertion, Group 2 does
were injected with PGF2 . A superovulation treatment similar to Group 1 was administered
in Groups 2 and 3, starting 48 h before CIDR removal. All does in these groups were
also cervically inseminated with fresh undiluted Boer goat semen 24 h and 36 h following
CIDR withdrawal. Embryos from all 3 treatment groups were flushed on day 6 following
AI. Does in Group 1 responded to the short oestrous synchronisation protocol before
the administration of a superovulation treatment (71.4% response), with time to onset of
oestrus of 37.2±0.7 h and duration of an induced oestrous period of 36.4±0.5 h being
recorded. Following superovulation only two does exhibited signs of oestrus in Group 1,
while Groups 2 and 3 exhibited a 100% oestrous response. Groups 1 and 2 recorded similar
intervals to the onset and durations of the induced oestrous period. The number of ovulations
per donor was significantly lower in Group 1 (4.0±0.7), compared to Groups 2 and
3 (14.5±0.6 and 16.5±0.8, respectively), with no significant difference between Groups 2
and 3. The Day 0 protocol (Group 1) also resulted into a significantly lower total number
of structures recovered, compared to Group 3. Groups 2 and 3 recorded a relatively similar
number of structures recovered. The number of embryos recovered was significantly lower
(P < 0.01) in Group 1 (0.2±0.1) than in Group 2 (13.2±0.5) and Group 3 (11.5±1.1), with
the mean number of unfertilised ova and degenerated embryos being similar for all 3 treatment
groups. Groups 2 and 3 also produced a similar number of transferable embryos. The
blood progesterone concentrations followed a similar trend in the 3 treated groups, from
CIDR insertion to embryo flushing. However, the mean serum progesterone concentration
was significantly lower on day 4 in the Day 0 group, compared to Groups 2 and 3. The inclusion
of PGF2 treatment in the superovulation protocol for Boer goats had no beneficial
effect, while the Day 0 protocol engaged in this trial, resulted in a lower superovulation
response. Further research is warranted, focusing on synchronisation, time when initiating
superovulatory treatment and AI to improve the embryo yield in goats
