In the past, Dutch breeding stallions often traveled extensively during the breeding season, transported by truck or trailer. The stallion owner would usually bring the stallion to the mares for natural covering. Not only was this a demanding lifestyle, but stallions were also sometimes kicked by mares that were not quite in heat yet. Other stallions serviced mares at the stud, but even then it involved one mount per mare.

Artificial insemination

With the introduction of artificial insemination (AI) in horses, this changed significantly. Stallions now usually remain at their own stud, while semen doses are transported to the mares. From a single mount and ejaculation, multiple doses can be produced, meaning the stallion does not need to mount as often per mare. However, there are strict requirements regarding semen quality, and stallions must be regularly tested for contagious equine diseases. In some cases, a stallion may also need to undergo a 30-day quarantine before the breeding season. For some breeds and individual stallions, natural covering is still common, but in major studbooks, breeding is almost always done via AI or even more advanced techniques such as in vitro fertilization (IVF).

Powerhouses

A breeding stallion is usually an impressive sight, with a strong neck and well-developed muscles. They must be in excellent condition, as breeding is comparable to top-level athletic performance. To produce high-quality offspring, a stallion must generate high-quality semen, which requires significant energy as well as sufficient nutrients, vitamins, and minerals. The act of mounting itself is also physically demanding. For this reason, most stallions cannot combine intensive competition sport with frequent breeding, as it would require too much energy and physical resources. On the other hand, many stallions only cover one or a few mares per year. For these animals, the physical effort of breeding should still be considered, but it usually does not pose a long-term limitation on other activities.

Frozen semen and sport

Because semen doses can be frozen, a breeding stallion can nowadays compete in (international) sport while also producing offspring. Performance in sport is very important for many dressage and jumping stallions, as it helps them gain recognition and demonstrate their qualities. Breeders often prefer to see stallions in person at competitions, inspections, or stallion shows before making a final decision for their mare. It is common to see that stallions who have had successful sport careers spend more time breeding later in life. This is not only because they become more popular after proving themselves, but also because fertility rates with fresh semen are still higher than with frozen semen. In addition, the costs for mare management are lower when fresh semen can be used. Breeders therefore generally prefer “fresh.”

Welfare of breeding stallions

The welfare of breeding stallions has improved significantly over the past decades. With the introduction of AI, traveling to mares has largely been eliminated, and stallions no longer need to mount as frequently. They are also no longer at risk of injury from kicking or biting mares. Nowadays, breeding stallions are given more freedom of movement, although social contact is still not always common. Owners are often concerned that these valuable animals might injure themselves during play or fighting. Whether a breeding stallion has a good life therefore varies greatly from one horse to another and also depends on the animal’s character. Stallions are also often presented at shows, where loud music and applauding crowds can sometimes cause stress. However, some stallions cope well with this and even seem to enjoy the attention. Perhaps the biggest threats to their welfare are the expectations and interests surrounding them. Owners sometimes need to be very strong-willed to prioritize the horse’s well-being when significant money or prestige is at stake.

Supporting fertility with vitamin E

Because breeding is a demanding task, proper nutrition is essential for stallions. They need sufficient vitamins, minerals, and nutrients to perform their role effectively. Vitamin E plays a particularly important role in fertility and is therefore essential for all breeding animals, both mares and stallions. Vitamin E is naturally abundant in grass, but if a horse has little or no access to pasture, supplementation is recommended. In stallions, semen quality and sperm motility improve with additional vitamin E—this has been scientifically demonstrated. This increases the likelihood of successful fertilization. When choosing a vitamin E supplement, it is important to be cautious: cheaper products often contain forms of vitamin E that are poorly absorbed by horses. The best option is a liquid supplement containing natural vitamin E, specifically the isomer RRR-α-tocopherol, which is found, for example, in wheat germ oil. Other isomers are poorly absorbed and are therefore often a waste of money. A combination of vitamin E and antioxidants often yields the best results.