The effect of a warmed enema during ovum pick-up on subsequent oocyte maturation in Southern white rhinoceros .

BACKGROUND

Rhinoceros are currently one of the most threatened mammal species globally. Slow population growth, increased poaching and habitat destruction have led to increased conservation efforts for each species. Assisted reproductive technologies (ART) have been implemented in an attempt to aid reproductive outputs for the conservation of these endangered species. Developing species-specific ART programmes for wildlife have been challenging. Temperature control during oocyte recovery is essential for ensuring success.

OBJECTIVE

This study is the first to investigate the effect of enema warming prior to trans-rectal ovum pick-up (OPU) on oocyte maturation in Southern white rhinoceros .

METHODS

OPUs were performed on 20 rhinoceros cows from three different game farms in South Africa; oocytes were transported to one of two fertilisation laboratories for culture. The enema fluid was either warmed to 32 °C or not warmed prior to the OPU. Location of the farm, the different laboratories, ambient temperature, season, aspiration probe temperature, media type and enema temperature were investigated as predictor variables for oocyte maturation success.

RESULTS

After considering all other potential covariates, warming of the enema fluid was the only independent predictor of oocyte maturation success during this study.

CONCLUSION

Oocytes retrieved from rhinoceros cows that received an enema warmed to 32 °C were 2.3 times more likely to mature compared to oocytes from cows that received an unwarmed enema; the findings can be implemented in other rhinoceros ART programmes and in conservation efforts of other endangered mammalian species.