CHOOSING a stallion for a mare will always involve judgement, knowledge of the family and a clear idea of the horse a breeder hopes to produce. Horse Sport Ireland’s recent new Irish Sport Horse Report does not replace any of those things, but it gives breeders something increasingly valuable to put alongside them: a picture of what is happening across the population as a whole.

Prepared by HSI geneticist Dr Jennifer Doyle, the report brings together breeding, pedigree and performance information on the Irish Sport Horse population.

Some of its figures are striking. Of the Irish Sport Horse foals born in 2016, 44% were by foreign, predominantly warmblood, sires. By 2025, that had risen to 54%. Just 23% of 2025 foals were by Irish Sport Horse stallions, although 72% were out of ISH mares.

For an individual breeder, those figures do not mean that using a foreign sire is either right or wrong. Their value is in showing the direction in which the population is moving.

A useful benchmark

The same applies to thoroughbred blood. The average 2025 ISH foal carries 43% thoroughbred blood, while Irish Sport Horses registered with the FEI for eventing in 2026 average 50%.

That does not establish that 50% Thoroughbred is an optimum for an event horse. Performance is influenced by many factors and the current FEI population represents horses produced from breeding decisions made years ago. But it does give breeders a useful benchmark against which to consider their own mares and proposed matings.

The report also reveals just how broad the sire base currently is. Some 789 stallions contributed to the 4,245 ISH foals so far registered from the 2025 crop. That provides considerable choice, but numbers alone cannot tell us whether valuable bloodlines are being maintained or whether particular successful lines are becoming disproportionately influential.

This is perhaps where the report is most useful. Rather than providing a recipe for breeding the next championship horse, the report perhaps allows breeders to place their individual decisions within the bigger picture. If, for example, a breeder repeatedly adds continental blood to an already continental-influenced mare family, the report provides context for considering what may gradually be gained, or lost. Likewise, a breeder producing event horses can compare the blood composition of their stock with the population currently competing internationally.

Following fashion

With 2,263 Irish Sport Horses registered with the FEI by the end of July 2026, the breed remains an important international performer.

The real potential of reports such as this will come as population, genomic and performance data are increasingly connected over successive generations. For breeders, that could ultimately mean something more useful than following fashion: better evidence with which to make an informed mating decision.

IRISH breeders have more data at their fingertips than ever before. But can it actually help answer the question that matters each spring: which stallion should I use on my mare?

For generations, breeders have chosen stallions through a mixture of pedigree knowledge, experience, observation and instinct. Increasingly, however, data has become another tool at our disposal.

HSI’s Irish Sport Horse Report is part of a much bigger pool of information being assembled around our breeding population, including pedigrees, competition results, linear profiles, Estimated Breeding Values (EBVs) and genomic information. So how might breeders actually use it?

The starting point should be the mare. Rather than asking which is the “best” stallion, the more useful question is: what am I trying to retain or improve in my mare? That might be jumping ability, movement, conformation, temperament, athleticism or the proportion of thoroughbred blood. It might also mean avoiding doubling up on a weakness or on closely-related bloodlines. This is where HSI data can add another layer of evidence.

An EBV, for example, attempts to predict the genetic merit an animal will pass to its offspring. HSI’s show jumping EBVs use pedigree and performance information from the horse itself and its relatives and progeny. An EBV of 100 represents the breed average. A stallion with a substantially higher figure is therefore predicted to pass on greater genetic potential for the trait being measured.

There is evidence that this matters. HSI’s 2025 genetic evaluation reported that offspring of ISH stallions with show jumping breeding values above 130 were more than 20 times as likely to compete internationally as offspring of stallions with values below 100.

However, an EBV is not a mating recommendation.

The wrong stallion

A stallion can have an excellent breeding value and still be the wrong stallion for a particular mare. Breeders also need to look at the reliability attached to an EBV. A well-established stallion with numerous competing offspring provides considerably more information than a young sire with few progeny. HSI considers breeding values above 90% reliability very reliable, while those between 30% and 50% have poor reliability and may change as more information becomes available.

Linear profiling can provide another piece of the jigsaw. Rather than simply describing a horse as having “good conformation”, linear profiling records individual characteristics in a standardised way. Comparing the mare’s profile with that of a potential stallion can therefore help a breeder think more systematically about where a mating might complement, rather than simply replicate, her characteristics.

Accuracy of information

Genomics potentially takes this further. HSI is now offering DNA-based services that can improve pedigree accuracy, identify relationships and breed composition and, as the genomic database develops, improve the accuracy of information including kinship and breeding values.

None of this means a computer can choose your stallion. The HSI report itself shows why judgement remains essential. The average thoroughbred percentage among 2025 ISH foals is 43%, compared with 50% among ISH horses registered for FEI eventing in 2026. That is useful context for an event breeder, but it does not mean that producing a foal with exactly 50% thoroughbred blood will improve its chances of reaching international level.

Likewise, breeding values cannot tell you everything about rideability, temperament, soundness, management or whether a particular combination of mare and stallion will work.

Perhaps the most useful way to think about HSI’s growing bank of information is not as a replacement for the breeder’s eye, but as a way of testing it. Choose the qualities you want to preserve. Identify the weaknesses you want to improve. Study the mare family. Then use pedigree, performance, linear and genetic information to ask whether the stallion you like is supported by the evidence. Good breeding will probably always contain an element of uncertainty. Data cannot remove that uncertainty, but it may help breeders make it a little more informed.

Association rather than cause

There are, however, limitations to how far breeders should take the findings. Much of the report describes what is happening within the Irish Sport Horse population, rather than demonstrating which breeding decisions produce better horses.

Comparisons such as the 43% average thoroughbred blood in 2025 foals versus 50% among current FEI event horses are interesting, but they show association rather than cause, while headline numbers of international horses are difficult to interpret without knowing success rates relative to the number originally bred.

Categories such as “foreign sires” also encompass a huge range of bloodlines and breeding objectives. Perhaps most importantly, qualities central to the traditional appeal and commercial value of the Irish Sport Horse, including soundness, longevity, temperament, rideability and suitability for amateur riders, are much harder to capture in population statistics.

The report provides a useful baseline, but breeders should probably be cautious about treating descriptive data as breeding advice. The challenge for future reports will be to move beyond telling breeders what the population looks like and towards evidence that helps them understand which breeding choices are actually producing sound, successful and saleable horses.