A. Most yearlings and two-year-olds can and will breed under good circumstances. There's probably not a horse practice without a firsthand story of the pregnant
Even though spermatozoa production begins as early as 12 to 14 months of age in most colts, results of numerous research trials recommend waiting until the stallion is 3 years old before using him as a breeding stallion. Daily spermatozoa production is also influenced by season.
One year old fillies are able to conceive but, usually, not to give birth to a living foal. Although embryo transfer allows the production of foals from mature mares with repeated pregnancy losses, no reports are available on the use of one year old fillies as embryo donors.
Putting your colts out with your fillies might be all right when they're first weaned, but by nine months or so, unless you want to risk an oops, it's a good idea to run them in separate herds.
Horses reach sexual maturity between 18 and 24 months of age. Testosterone not only causes stallion-like behavior, but also causes growth plates in long bones to close earlier than they would in a gelding, resulting in geldings growing taller.
Pregnancy: a recently castrated gelding can still get a mare in foal for some time after castration because of residual sperm in the urogenital tract. Recently castrated geldings should be kept away from females for at least 40 days.
Although most stallions begin to produce sperm as early as 12 to 14 months, most are at least 15 months or older before they can successfully breed. Few stallions are used at stud before two years of age and most stallions acquire full reproductive capacity at around three years of age.
At what age should castration happen? Colts can be castrated at any age. It is our preference to perform the castration when the colt is between 6-18 months old. This is because we feel that the younger the colt is when castrated, the fewer problems there are.
Geldings, while they no longer have the sex drive of a stallion, can still get an erection. Should a gelding mount and then penetrate the cervix of your mare, the pregnancy will likely be aborted.
If necessary, foals can be weaned as early as a few days post birth; however, the usual age for weaning is between 4 months and 6 months. Newborn foals rely on the mare for nutrition, protection and security.
Disadvantages of breeding mares on foal heat are:
Lower pregnancy rates achieved for mares mated on foal heat compared to mares mated for the first time on later postpartum estrous periods.
There is specific terminology used to describe horses depending on their age: Foal: A horse of either sex less than one year old. Yearling: A horse of either sex that is between one and two years old.
As a result, stallions have evolved strategies to safeguard against raising other stallions' offspring. And one of these instincts is to kill young foals – especially males – that are probably not their own, if the opportunity arises.
The most likely reason that mares lie down after mating is because they are overwhelmed and need to rest to bring their heart rate back down to normal levels. Stallions can be aggressive and hyperactive when courting and mating, and horses are socially sensitive creatures.
With mares, there is the risk of the colt mating with them, leading to unexpected and unwanted pregnancies. Even if separated from a herd of mares, the sexual urge of the colt may be so great that they will go to any length to reach the mares. Unfortunately this can result in injury to the colt, which can prove costly.
Colts that are castrated before the onset of puberty (usually about twelve months) will grow taller than their unaltered herdmates. The reason that some stallions may look bigger than many geldings is that they are way overweight.
Thanks to a survey of EQUUS readers we conducted decades ago, we know that geldings may show numerous stallion-like behaviors, such as lip curl (the flehmen response). They may try to breed mares, herd their mares and fight with other geldings. They may behave aggressively toward people and attack foals.
Once a stallion has been castrated, he can no longer reproduce. A vet removes both testicles and all of the supporting structures.
A gelding is termed "proud cut" if the horse has been castrated, but all or a part of a testis remains after castration. This can happen when one testis has not fully descended into the scrotum (cryptorchid) when the castration is performed.
Weaning is usually done somewhere between 4 and 7 months of age, although some ranches leave their foals on the mares a bit longer.
A colt is a male horse, usually below the age of four years.
Mature stallions can breed two or three mares a day throughout a long breeding season and maintain a good level of fertility, but young stallions should not be expected to handle this level of work.
In the wild, herd stallions recognize and protect their offspring, and observers have often seen dad babysitting the kid while mom takes a well-earned break.
A mare who's had no foals, or only one or two, shouldn't be bred past 16. Mares who have been regularly bred, and are able to manage pregnancies well, can be bred as old as 25, though most breeders will stop at 23.
Semen remains in the horse's accessory sex glands and the portion of the vas deferens not removed during surgery. There is usually enough present for one ejaculation. Therefore, gelded mature horses should be quarantined from mares for 14 to 30 days post-surgery.