What is a Mare Horse?

what is a mare horse

A mare horse is an adult female equine. In Thoroughbred horse racing, a mare is a female horse older than three years of age. In contrast, a filly is a horse younger than three years of age. The term mare is also used to describe a pregnant mare.

Symptoms of a mare horse

When a mare is about to give birth, it is important to monitor her for any early signs of labor. She will begin to sweat and urinate more frequently, lie down a lot, and twitch her tail. She may also be restless, anxious, or irritable. She may also show signs of mild colic. She will break water when her uterus contains between two and five gallons of uterine fluids.

Estrous cycle of a mare horse

A mare’s estrous cycle occurs every 21 days. During this period, mares become physically uncomfortable and irritable. Her hormones, progesterone and estrogen, also fluctuate. A vet can give a mare herbal supplements to help regulate her estrous cycle.


A mare that is undergoing pregnancy may have retained her placenta. A retained placenta is typically visible, although partial retention is possible. If you suspect that your mare has retained her placenta, it is best to consult a veterinarian to help you remove it safely. The veterinarian can perform a manual exam of her uterus, which will usually reveal the remnants of the placenta. After a thorough evaluation, your veterinarian can start treatment.

Moodiness of a mare during estrus

Mares often exhibit behavior changes that are related to their estrous cycle. These changes can interfere with training, management, and performance. Often these changes are blamed on the mare’s hormone levels, but they can also be caused by other problems, so it’s important to figure out what’s causing the problem.


A mare’s estrous cycle is a two-phased process. The first phase of estrus, called estrus, lasts two to eight days, and the second phase, called diestrus, lasts 14 to 16 days. During estrus, the mare’s reproductive hormones begin to flow, triggering her to ovulate.

Placenta in a mare’s belly

The presence of a placenta in a mare horse’ belly is common during pregnancy. It can be detected through early transrectal ultrasound, which is available commercially. The presence of a placenta is a serious concern because a mare’s uterus is only large enough to carry a single foal. Most twin pregnancies are lost at mid or late gestation, making it extremely difficult for a mare to deliver twins.

Keeping a mare separate from a filly during diestrus

Keeping a mare horse separate from suckling fillies during diestrus is one of the best ways to prevent unwanted pregnancy. This period occurs after the mare’s estrus, which lasts between three and seven days. During diestrus, a mare is no longer receptive to stallions, and her estrus symptoms will have disappeared.

Care for a mare during foaling

A mare may be in the foaling stage for several hours or even days. This time is critical for the mare and foal, so it is important to keep a close eye on them. There are some symptoms that may resemble colic or sign of an infection, and they are best observed by a veterinarian. During this time, the mare will urinate often because the pressure on her bladder is very high. When the mare breaks water, the foal will leave the mare’s body.