Twenty-four adult hinds, treated with intravaginal progesterone (CIDR), received a daily intramuscular injection of either 0, 4, 7.5 or 11 mls of dextra-charcoal treated bFF (n = 6 per group) on days -1, 0 and +1 from the time of CIDR withdrawal.
After CIDR removal, plasma progesterone concentrations declined in all animals. In control hinds, oestrus occurred 2-3 days later and mean plasma progesterone concentrations began to increase thereafter. In bFF-treated hinds, oestrus was delayed by 3-5 days, and plasma progesterone concentrations remained low for at least 7 days after CIDR withdrawal. Plasma LH concentrations were 2-3 fold higher in the bFF- treated groups, relative to the control hinds, for at least 6 days after the end of bFF treatment. Twin ovulations were recorded in 1/6 control and 5/17 treated animals. At pregnancy diagnosis, 10/23 hinds were pregnant having conceived at the treated oestrus (3/6 control and 7/18 treated), but none had more than one foetus. There was no evidence of a dose-response to bFF treatment.
These results indicate that in the hind, bFF can be used to manipulate the timing of oestrus and ovulation rate. A component(s) of bFF may thus have the potential to regulate fecundity in deer.
Keywords: NZSAPAB; Follicular fluid; red deer; oestrus; progesterone; LH; ovulation rate