The use of conventional dairy semen has almost halved over the last four years.

Data from ICBF shows that in 2021, approximately 950,000 conventional dairy semen inseminations were carried out in Irish herds while this was down to just over 517,000 in 2024, a 45% reduction.

Overall AI usage in Ireland is stable at 1.35m inseminations in 2024, so the falloff in conventional dairy inseminations is being offset by increases in sexed semen and beef AI usage.

The number of sexed semen inseminations has increased from 60,000 serves in 2020 to reach over 183,000 in 2024. The number of herds using sexed semen continues to grow annually, with almost 5,500 herds using sexed semen last year.

The most recent available data set suggests that best results with sexed semen are achieved with heifers.

Adjusting for EBI and days in milk, sexed semen achieved a 61% pregnancy rate to insemination with maiden heifers and a 50% pregnancy rate to insemination with cows.

The actual results are higher than this but because sexed semen tends to be used on more fertile cows to begin with, the adjusted figure is a better comparison.

On a relative basis, sexed semen was 93% as good as conventional semen on heifers and 87% as good as conventional semen on cows, based on the 2023 data presented by Stephen Butler from Teagasc at the ICBF breeding seminar late last year.

Male calves

If trends in sexed semen usage continues, Stephen said that the number of male dairy calves born in Ireland could be as low as 252,000 in 2026, down from 423,000 in 2022.

One of the risks identified with sexed semen is that over time farmers with a history of achieving good results could become complacent with the protocol.

Stephen identified three areas critical to the success of sexed semen: picking the right cow, inseminating at the correct time and handling the straw appropriately.

On dam selection, he said that heifers should be at target weight and have a body condition score (BCS) of 3.25 or greater at the time of AI.

We often consider heifers just in the context of weight and not BCS, so this is an interesting angle.

For cows, the criteria are more stringent.

He said that cows should be in lactation one to four and be calved more than 50 days. On BCS, only cows with a score of three or more should be put forward for sexed semen.

Cows with any health issues since calving should not be given sexed semen either, he said.

For both cows and heifers, only high EBI animals should be bred with sexed semen, the suggestion being that animals below the herd average should be excluded and bred to beef. Stephen also said that both heifers and cows should be cycling regularly prior to insemination.

Cow selection

The whole area of cow selection for breeding is proving to be as big an area as bull selection.

It was always thus, but because there was limited opportunity to select what females to breed replacements from, it was rarely discussed.

Where there are more cows suitable for sexed semen than required, selection criteria should always be based on EBI.

I hear of some farmers looking at milk recording results to determine what cows to breed replacements from, but it is the EBI report and not the milk recording report that the decision should be based on.

Genetics are inheritable and that is what counts. On the law of averages, the highest genetic merit cows should also be the highest production cows but it may not always be the case.

Genes will be passed on but if a cow is high-yielding because she gets fed more than others, that won’t be passed on.

In short