The use of sexed semen continues to grow in Ireland, with 15% of all dairy AI straws used in 2023 sexed sorted semen. This is up from just 2% in 2019. The ramping up of sexed semen usage is as a result of better availability of ‘in demand’ bulls as sexed semen and the move away from dairy bred male calves.

While the traditional view of sexed semen was that it allowed extra heifer calves, in reality sexed semen is used in Ireland to produce more beef calves. This is because farmers can select what cows they want to breed heifers from and put the rest in calf to higher value beef AI.

If this trend towards more sexed semen continues, what implications could it have for the breeding programme? To answer this, we need to understand what currently happens. At this time of year, AI companies will be scouring the ICBF database of matings to find planned pregnancies where a bull calf would be of interest to them.

The AI companies will contact the owners of cows and ask that if the pregnancy results in a live male calf, that the farmer gets the calf genotyped and if the results are to the companies liking, the calf will be purchased.

Hundreds of bull calves are purchased by AI companies in Ireland in this way each year. Not all will make it to the AI catalogues for various reasons. Prospective AI bulls need to have a high and well balanced EBI; they need to have a good pedigree and ideally not closely related to any already widely used bulls.

The rollout of the National Genotyping Programme will increase the quality of the information available to AI companies as more reliable proofs on cows and calves will be available in the coming months.

However, the increased use of sexed semen, particularly in the higher EBI and more technically efficient herds may mean that genetic gain for EBI could slow down, rather than speed up. This is a concern that some farmers and those in the industry have about the increased use of sexed semen.


Last autumn, the Irish Farmers Journal travelled to Denmark to meet with Viking Genetics, the breeding co-operative overseeing the breeding programme in Denmark, Sweden and Finland. Perhaps not surprisingly, the use of sexed semen in these countries varies by breed, ranging from 30% usage on Holstein Friesian cows to 95% usage on Jersey cows.

Given such high usage of sexed semen on Jerseys, Viking Genetics have significantly altered how they source and select future bulls. Interestingly, the process starts with heifer calves, not bull calves.

The AI station purchases high genetic merit heifer calves with genetics that are of interest to them, i.e. potential bull dams. Within the Jersey breed, it genotypes 200 heifer calves annually and purchases 85 of the best. About 90 Swedish Red and 100 Holstein Friesian heifer calves are also purchased.

These heifer calves are then reared by Viking Genetics in one of their stations. When they reach puberty the heifers are flushed and their eggs are mated using in-vitro fertilisation (IVF) and in-vitro production (IVP) with semen from high genetic merit bulls.

Commercial farms

The resultant embryos are planted into recipient cows on commercial farms, with an agreement that the resulting bull calf will be sold back to the AI company. These bull calves are then genotyped and the best ones are put forward to AI.

Some of the 440 cows on the Oleson farm in Denmark.

After a number of rounds of egg (oocyte) collection, the farmer who bred the heifer is given first refusal to buy the heifer back. The AI company itself is not involved in calving cows or milking cows. All it does is gather the elite heifers and produce viable, male, high genetic merit embryos and arranges for these to be transferred on to recipient cows on commercial farms.

Danish farmer Bent Oleson is involved with Viking Genetics on the Jersey breeding programme. While the farm has bred over 20 bulls for AI in the past, it is now bull dams that the AI company is purchasing from Bent. In addition, the Oleson herd is one of 15 to 20 farms that provide recipient cows for embryo transfer. These cows carry the embryo that was created in a lab after flushing the heifers.

Genetic merit

Like most Jersey herds, no conventional Jersey semen is used on the 440 cow farm located in the northern part of Denmark. The best cows get served with sexed Jersey semen.

They have two opportunities to be served with sexed semen and if they fail to go in calf after the second serve they will be served with conventional Belgian Blue AI. Heifers get three chances at sexed Jersey before getting conventional Aberdeen Angus AI.

The lower genetic merit cows start off by getting served to sexed male Belgian Blue AI and after two chances at this will then get conventional Belgian Blue AI. The net result is that there is practically no Jersey male calves born on the farm and that all calves have a market.

“I can sell the beef calves at three to four weeks of age and have a deal done with local buyers who pay around €1.34 per kilo of liveweight.

“The key for me is that there is someone there to buy them and that we don’t have to deal with a male Jersey calf that nobody wants. Calving difficulty isn’t an issue and the Jersey cows are well able to handle a Belgian Blue. We’ve had two caesareans in recent years and both involved Jersey on Jersey.


“We have all the cows in the herd genotyped so we have really good information on each cow. I can really see the benefit of the whole breeding policy on the ground. Heifers are more even and the genetic merit of the bottom 25% of the herd is raised because we are only breeding replacements from the best cows,” Bent says.