The reproductive success of bovine sperm after sex-sorting: a meta-analysis

Reese, S. and Pirez, M. C. and Steele, H. and Kölle, S.

Sci Rep (2021) 11: 17366

DOI: 10.1038/s41598-021-96834-2

Abstract

In the three decades since its inception, the sex-sorting technology has progressed significantly. However, field studies report conflicting findings regarding reproductive outcomes. Therefore, we conducted this meta-analysis of all trials published between 1999 and 2021. Non-return rates after 24 or 60 d (NRR 24/60), pregnancy, calving, abortion, and stillbirth rates were compared after AI with sex-sorted vs non-sorted sperm. Additionally, the impact of recent developments in the sex-sorting technology was assessed. Of 860 studies found, 45 studies (72 trials) provided extractable data and were included. Overall, the results of this meta-analysis provided evidence that the NRR 24/60 was diminished by 13%, pregnancy rates were reduced by 23% (25% cows, 21% heifers) and calving rates were reduced by 24% when using sex-sorted sperm. Enhancing the dosage to 4 million sex-sorted sperm/straw (including recent improvements, high vs low dose) as well as using fresh sex-sorted sperm (sorted vs non-sorted) increased pregnancy rate ratios by 7 percentage points. The refinement of the sex-sorting technology after 2015 resulted in a lowered reduction of pregnancy and calving rate of 19% and 23%, respectively. Whereas abortion rates were similar, the stillbirth of male calves was increased by 6.3%.

Citation

Reese, S., Pirez, M. C., Steele, H., & Kölle, S. (2021). The reproductive success of bovine sperm after sex-sorting: a meta-analysis. Sci Rep, 11(1), 17366. https://doi.org/10.1038/s41598-021-96834-2

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