Endocrine responses and conception rates in fallow deer (Dama dama) following oestrous synchronization and cervical insemination with fresh or frozen–thawed spermatozoa
in ReproductionIn Expt 1, 59 mature fallow deer does were allocated to six treatments (n = 9–10 per treatment). Does assigned to treatments 1, 2 and 3 each received an i.m. injection of 500 μg cloprostenol on day 13 of a luteal cycle. Does in treatments 2 and 3 received 50 or 100 iu pregnant mares' serum gonadotrophin (PMSG), respectively, at the time of prostaglandin administration. Does assigned to treatments 4, 5 and 6 each received single intravaginal controlled internal drug release (CIDR) devices for 14 days. Does in treatments 5 and 6 received 50 or 100 iu PMSG, respectively, at the time of CIDR device withdrawal. Incidence of oestrus was higher following treatment with CIDR devices than with prostaglandin (29 of 30 versus 12 of 29, P < 0.001). PMSG induced earlier onset of oestrus (34.6 ± 0.9 h versus 44.7 ± 2.4 h, P < 0.01) and reduced the range in the time to onset of oestrus (from 22 to 8 h for prostaglandin-treated does and from 36 to 14 h for progesterone-treated does). The number of LH surges was higher following treatment with CIDR devices than with prostaglandin (10 of 12 versus 3 of 12, P < 0.01). The overall mean peak LH concentration and time to LH peak were 30.2 ± 3.4 ng ml−1 and 45.2 ± 2.2 h after prostaglandin administration or CIDR device withdrawal. The overall median time of ovulation was 26 h after the onset of oestrus. The administration of 100 iu PMSG stimulated the incidence of luteinized follicles and twin corpora lutea. In Expt 2, 105 does were allocated to four treatments (n = 26–27 per treatment): prostaglandin; prostaglandin with 50 iu PMSG; CIDR devices; or CIDR devices with 50 iu PMSG. The does were inseminated cervically with 200 × 106 frozen–thawed spermatozoa 12 h before the median time of ovulation as calculated for each treatment in Expt 1. The proportion of pregnant does was higher following treatment with CIDR devices than with prostaglandin (38 of 52 versus 28 of 53, P < 0.05). PMSG was beneficial only for does treated with prostaglandin. In Expt 3, 93 does were treated with CIDR devices for 14 days and inseminated cervically with 50 × 106, 25 × 106 or 12.5 × 106 fresh spermatozoa at 12 h before the median time of ovulation. The concentration of spermatozoa had no effect on conception rate. The overall pregnancy rate was 76.3%.
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