Laparoscopic intra-uterine insemination of fallow deer with frozen-thawed or fresh semen after synchronisation with CIDR devices

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Abstract
This study investigated the efficacy of fixed-time laparoscopic intra-uterine insemination of farmed fallow deer (Dama dama) with frozen-thawed or fresh semen. In the trials with frozen-thawed semen, a total of 547 mature non-lactating does across five New Zealand farms were used. For oestrous synchronisation and artificial insemination, a standard control regimen was applied to at least 30% of the does on each farm, involving the insertion of single CIDR type-G devices intravaginally for 14 days, deposition of 50 × 106 frozen-thawed spermatozoa at 65 hours after withdrawal of the CIDR device and the continuous presence of vasectomised bucks from the insertion of the CIDR device until 10 days after insemination. Various aspects of this protocol were changed for the remaining does on each farm, including inseminations at 60 or 70 hours, the absence of vasectomised bucks, insemination with 25 × 106 or 10 × 106 spermatozoa, synchronisation with CIDR type-S devices and synchronisation with prostaglandin. The conception rate, based on rectal ultrasonography at 45 days after insemination, was 67% across all treatments (n=547). Corrected conception rates (± s.e.), calculated following between-farm adjustments, were 67± 3% for the control regimen, 67 ± 9% and 73 ± 8% for inseminations at 60 and 70 hours respectively, 61 ± 9% for absence of bucks, 80 ± 8% and 74 ± 9% for inseminations with 25 × 106 and 10 × 106 spermatozoa respectively, 62 ± 10% for CIDR type-S device synchronisation, and 49 ± 10% for prostaglandin synchronisation Despite apparent differences, none of the treatments resulted in adjusted conception rates that were significantly different from the control regimen (P>0.10). In the trials with fresh semen, 216 does in the USA were inseminated at 69–71 hours after withdrawal of the CIDR device using either cryopreserved semen from New Zealand (n=158; 25 × 106 spermatozoa per inseminate) or fresh semen (n=58; 7.5 × 106 to 20 × 106 spermatozoa per inseminate) collected less than 10 hours earlier. The overall conception rates were 77% and 81% respectively, with no significant differences between semen type (frozen v. fresh) or fresh spermatozoa number per inseminate (P>0.10). A further 102 does in New Zealand similarly received fresh semen from a 3/4 Mesopotamian buck. Doses of 10 × 106 (n=35), 5 × 106 (n=32) or 2.5 × 106 (n=35) spermatozoa per inseminate were delivered at 69–71 hours after withdrawal of the CIDR device. The conception rates were 77%, 66% and 51% respectively, reflecting a dose effect (P<0.05). However, 1/4 Mesopotamian does in the group (n=19) exhibited higher conception rates (95% overall) irrespective of semen dose, possibly indicating a semen/recipient genotype interaction. It is concluded that laparoscopic intra-uterine insemination of fallow deer with frozen-thawed or fresh semen at fixed intervals after removal of a CIDR device can give acceptable conception rates under a range of on-farm management options and semen doses.