In recent years, you increasingly see foals being born in March, February or even January. Among some breeders, it seems to have become something of a competition. In nature, the period between April and June is the best time for a foal to be born. Then it is warmer and there is plenty of spring grass from which the mare can make nutritious milk. So why are there so many early foals? As the days get longer and the grass starts to grow, the mare's hormone system comes into its own. Although the first stallionhood often occurs as early as February, there is usually more chance of conception in April, May and June. This is also the natural mating period. The horses are already shed, the immune system is in order and there is plenty of nutritious grass available.

Shift

A mare is usually over 11 months pregnant. After the foal's birth, it takes about a week for the first heat (the foal's heat) to return. If you can successfully cover on that, the foal will come about three weeks earlier the following year. But that doesn't happen very often, and many breeders prefer to give their mares a little longer after giving birth. The first normal stallionhood is about 31 days after giving birth. That means the next foal will be born around the same date as this year's foal, on average a few days later. But by no means all matings succeed, and if it only works on the second or third mating, you will get a 'later' foal. After mid-August, almost no more mating takes place; if it has not succeeded by then, you have to skip a year. Because of this 'shift effect', breeders prefer not to wait too long before mating, especially when the mare is mated for the first time or has been gestating for a year. And if it does succeed the first time, you suddenly have a very early foal. That is part of the explanation for foals born in January, February or March. Breeders like to skip as few years as possible with their mares.

Stallion selection cause early foals

A second reason for wanting an early foal is stallion inspections and ability tests. In most Dutch studbooks, it is (still) the case that the first viewing of stallions takes place at the end of the year in which the stallions turn two years old. Early foals are easily 33 or 34 months old at that time, foals born in July 27 or 28 months. In that period of a young horse's life, that can make a huge difference in maturity and therefore result of the inspection. At the first viewing, the horses walk on a rope or loose through the track. A few months later, the use tests follow, where they also have to show their qualities under saddle or in harness. Nowadays, the KWPN has a rule that horses in a performance test, such as the performance test or the EPTM tests for mares, must be at least 36 months old. This means that for horses born in June or July, you have to wait much longer to offer them for this. And not everyone wants to do that, also because of the extra costs for rearing. In general, the ages at which young horses are judged are shifting in recent years. The studbooks no longer want very young horses in the ring, because of animal welfare. This is a good thing, but also has the unintended side effect that breeders prefer to have an 'early' foal.

Consequences for the mare

If you want to cover a mare early on, it is often necessary to spray her in heat. The cycle of horses responds to day length and sunlight, so good-quality stallions often only come in April, May and June. If you want to cover earlier, the vet may give a hormone preparation to trigger the stallionhood. Some mares don't seem to suffer from this at all, in others it causes side effects such as sweating or even mild colic. These often pass within a few hours. The stallion injection can disturb the cycle and if the mare has just been in heat, it does not always work. Sometimes there is an egg, but the uterus is not yet ready for pregnancy. If the mare is put at a stallion station for mating, the stress of moving can cause the cycle to be disrupted or the stallionhood may not get going properly anyway. If it does succeed in injecting the mare with good stallionhood, insemination is usually possible after a few days. What also happens is to promote ovulation when the breeder and vet already know that the mare is in heat. This happens regularly in early spring, as some mares become in heat then, but do not always release the egg to the uterus.

Consequences for the early foal

Many hobby breeders, who only occasionally have a foal for fun, do not want an early foal at all. This is because it is less good for mare and foal and also very impractical. A foal born as early as January can go outside much less often than is good for it, especially if it freezes or snows. Foals need a lot of exercise to develop a strong skeleton and prevent problems such as OC(D). You would therefore prefer to put them outside for many hours very soon. Not only is that limited in early spring, but the animals often need to be blanketed. In addition, the mare needs a lot of extra feed to suckle her foal. For that, she is best off on rich, green, spring grass. But there is none of that yet in the first months of the year. That means more feeding, more mucking out stalls and more work with putting them in and out.

Preferably a bit later

The conclusion: it is much easier and better for both mare and foal if the birth date is a bit later. Of course, these days we often have mild winters and the grass sometimes starts growing weeks earlier than average. But it is still a gamble. In nature, April, May and June are the months when most foals are born. If you want to make things easier for yourself and your horse, as well as having a better chance of a successful conception and a healthy, strong foal, you should cover a little later.