The latest analysis undertaken by the Irish Cattle Breeding Federation (ICBF), Teagasc, and partner AI companies, Dovea Genetics, Eurogene/AI Services, Munster Bovine, and Progressive Genetics, has revealed that the overall pregnancy rate for sexed semen on Irish dairy farms is currently at 59%, compared to conventional artificial insemination (AI) at 64%. This indicates a relative pregnancy rate for sexed semen of 92%, which is a significant improvement from previous studies of sexed semen performance undertaken on Irish dairy farms in 2013, 2018, and 2019. These studies had all indicated that the relative pregnancy rate for sexed semen was approximately 84% of that achieved with conventional semen. However, it should be noted that each of these former studies was based on structured field trial data, whereas the current analysis is based on a statistical analysis of commercial field data, according to the ICBF.
The analysis was based on over 1.82 million conventional inseminations and 86,000 sexed semen inseminations completed over a five-year period (2018-2022). It is reportedly the most comprehensive analysis of the performance of sexed semen in a commercial field setting ever undertaken. All inseminations were completed by AI technicians from the partner AI companies, and pregnancy outcomes were validated against a subsequent birth event. No do-it-yourself (DIY) AI inseminations were included in the analysis. Statistical analyses were undertaken of the field data, with important factors such as year, herd, parity, days in milk, and cow genetic merit all accounted for in the model.
The results indicate that the relative performance over the five years was 92%, with incremental improvements in the technology also evident based on 2022 inseminations only (at 95% relative performance). This positive time trend is evident within the overall dataset, according to the ICBF, which highlights the ongoing improvements that there has been in the technology over the past five years. These include improvements in the technology (i.e., sexed ultra), increases in the sperm concentration per straw (most straws now contain 4 million sperm cells), and the establishment of two dedicated sexed semen laboratories in Ireland. The labs have helped ensure greater uniformity of the sexed semen product and markedly increased the number of high EBI bulls available, according to the federation.
Another outcome from the analysis was that when the raw phenotypic pregnancy rate was compared, then there was no difference in the pregnancy rates achieved by the sexed semen product compared with conventional AI (i.e., both had the same pregnancy rate). This occurred because sexed semen is being used selectively on heifers and the best fertility cows, with adherence to the strict protocols being promoted by Teagasc and the partner AI companies.
While the results from the current analysis were positive, they also highlighted the need for strict adherence to the protocols associated with the use of sexed semen. The federation said that the product will deliver good fertility performance, but only when used on heifers and/or dairy cows that are suitable for breeding (i.e., in good body condition, with sufficient days calved, etc.), and after strict adherence to all handling/AI protocols. Commenting on the analysis, Dr. Stephen Butler, Teagasc noted that the results were an important outcome for dairy farmers using (or planning to use) sexed semen this spring.
“In the past, the relative performance of sexed semen compared to conventional was seen as a big barrier to its potential usage by Irish farmers,” Butler said. “The fact that the relative performance is now 92% and improving, should hopefully encourage more dairy farmers to consider using the product in their breeding programmes this spring”. Dr. Margaret Kelleher, ICBF (who undertook the overall analysis), noted that the analysis had once again highlighted the significant herd-to-herd variation in the performance of the technology. “Like 2013, the difference in herd performance was striking with the top 10% and bottom 10% of herds achieving pregnancy rates for sexed semen of 73% and 40% respectively, with an average of 59%.”
Commenting on the results, Dr. Bernard Eivers, National Cattle Breeding Centre (NCBC), echoed the comments of Stephen and Margaret, noting that while the results were positive, it was critical that dairy farmers do not get complacent about the technology. “Yes, the results are good, but as an industry, we need to continue to ensure that the technology gets applied correctly on farms, otherwise there will be disappointments,” he said. “Our experience is that dairy farmers starting with the technology generally will try 10-15 straws, depending on their herd size, and we would encourage more farmers to adopt this approach this breeding season.”
Dr. Andrew Cromie, general manager for Sexing Technologies Europe, added: “It is a fantastic endorsement of the collaborative nature of the Irish cattle breeding industry that this sort of comprehensive analysis, incorporating almost two million insemination records, could be undertaken. The fact that dairy farmers can now have access to a technology that will help them address future challenges regarding dairy male calves, including also carbon inventories, is a significant step forward.” Cromie said he looked forward to continuing to work with ICBF, Teagasc, and the partner AI companies in the further roll-out of the technology across more dairy and beef farms in the future, including opportunities to look at fresh sexed dairy semen and sexed beef semen.