So, you have a filly, and want to breed her some day. Or maybe you have an older maiden mare, and want to know if it is okay to give breeding a try. There is lots to consider when deciding when a mare is ready to be bred.
Horses are sexually mature in their yearling year, although it is not unheard of for a filly to cycle before she is a full year old. Generally though, they are about a year and a half old the first time they come in season.
It is fully possible for a yearling to get in foal. If you have your fillies out with colts, it is essential to separate them by a year old. Colts can in fact become fertile as early as eight months old, so a pregnancy can happen far earlier than many owners imagine.
While it is possible to breed a yearling, most agree that it isn’t a good idea. Generally a yearling is the equivalent of a 12-14 year old girl. She is reaching sexual maturity, but has no actual maturity of her own. She is far too young to be pregnant and expecting a baby.
A two-year-old is a bit better, but still very young. Two-year-olds are only the equivalent of a 14-16 year old girl, still awfully young to be pregnant. By the time the filly foals, she will be the equivalent of 17. As you probably know from human pregnancies, teenaged mothers are much higher risk than mothers in their 20s. Likewise, there are more risks for a two-year-old filly when in foal, than there would be if she were bred a bit later in life.
By three, a filly is more mature and potentially ready to be bred. While many still feel that it is too early, she is the equivalent of a 16-18 year old, and will have the foal when she is the equivalent of 19. This is still young, but it is out of the danger zone, and she will be mature enough to have a better chance of being a good mother.
The ideal breeding age range for horses is 4-15 years of age. Many mares remain fertile into their 20s. This is because horses do not go through menopause the way that humans do. In fact, there are stories of mares well into their late 20s who were accidentally bred, and had a healthy foal the following year. While this is far from ideal, it is certainly possible.
If a mare has been bred before, it is usually not a problem to breed her later in life. However, a maiden mare is less likely to get in foal as she ages, and many not retain her pregnancy as well as a horse who has foaled before. After a mare reaches 15 years of age, her fertility is at risk. Many breeders will not breed a maiden mare who is over 15.
With good veterinary supervision, there is no good reason not to breed a maiden mare as old as 18. As long as the mare owner is aware of the reduced fertility, and understands that she may not catch at all, usually there is little real risk. Some stallion owners offer special deals to owners of senior mares, not charging the full stud fee until the mare is confirmed in foal, or even until the foal arrives.
If a mare has been bred regularly, she can safely continue to have foals until her mid 20s. As long as the owner carefully maintains her, and understands the increased risks involved in foaling a senior mare, it can be a good choice for the proven broodmare.
No matter the age of the mare, it is essential to carefully monitor your horse’s pregnancy