The opposite gender of a male horse is a female horse, which is called a mare. Horses are mammals that exhibit sexual dimorphism, meaning there are distinct biological differences between males and females of the species. Understanding the basic biology and terminology for describing male and female horses is useful for anyone who works with these animals.
Male Horses
Male horses are called stallions or colts. A stallion is a mature, uncastrated male horse over the age of four years. Colt refers to a young male horse under the age of four. Here are some key facts about stallions and colts:
– Stallions tend to be taller and more muscular than mares. Their average height ranges from 14.2 hands to 17 hands (a hand equals 4 inches).
– Stallions have 40 teeth, including the canine teeth often called tusks. Mares have 36 teeth.
– Stallions have larger necks and heads proportional to their body size compared to mares.
– On average, stallions weigh about 1,000-1,200 pounds compared to the average mare at around 900-1,100 pounds.
– Stallions have a thicker, arching crest along the top of their neck.
– Stallions have a stronger, louder neigh than mares.
– Stallions have larger feet than mares.
– Stallions have a straighter shoulder than mares, who tend to have a more sloping shoulder.
– The testicles are an obvious external anatomical difference between stallions and mares. Stallions have two testicles contained in a hair-covered scrotum between their hind legs.
Female Horses
Mature female horses are called mares. Young female horses are called fillies until about age four. Here are some characteristics of mares:
– Mares have a wider pelvis to facilitate carrying a foal during pregnancy. Their pelvis angles more than a stallion’s.
– Mares have two functioning mammary glands used to nurse foals. Their udders fill with milk after they give birth.
– Mares have a vulva and clitoris under their tail instead of a penis and scrotum. The vulva provides the opening to the uterus and vagina.
– Mares come into heat or “estrus” during spring and summer. This is when they can become pregnant. Their heat cycle lasts about 21 days and occurs from March to September in the Northern Hemisphere.
– When in heat, mares exhibit behaviors like frequent urination, vocalizing, and holding their tail to the side. Stallions detect their scent and become sexually excited.
– Mares can become pregnant for about 5-7 days of their 21-day estrus cycles. They carry a foal for approximately 340 days, or 11 months, before birth.
Breeding and Reproduction
To produce offspring, a stallion must breed with a mare. Here is an overview of horse mating and reproduction:
– Horses most commonly breed naturally through live cover, meaning a stallion mounts a mare and intromits his penis into her vagina to ejaculate semen. This takes place when the mare is in estrus.
– Stallions have large, pendulous testicles to produce large volumes of sperm. A healthy stallion can produce over 1 billion sperm in a single ejaculate.
– During mating, the stallion displays a characteristic upper lip curl called the Flehmen response. This facilitates scent detection and helps stimulate the stallion.
– Mares carry their foals for approximately 340 days before giving birth. This gestation period is similar to humans.
– Most mares give birth alone, at night, and quickly. Labor lasts only about 10-30 minutes on average.
– A newborn horse is able to stand on its own and walk within hours after birth. The foal immediately begins nursing from the mother mare.
– Mares produce milk from their mammary glands to feed the foal. Lactation can last over 1 year but most foals are weaned by 6-7 months old.
Castration
Many male horses are castrated, or gelded, to make them easier to manage. Here’s an overview of castrating horses:
– Castration involves surgically removing a stallion’s testicles to prevent reproduction and reduce masculine behaviors.
– Most colts are castrated by 6-12 months of age. The surgery has a high success rate and is usually done under sedation by a veterinarian.
– Common castration methods include closed, open, standing, or recumbent techniques. Closed castration has the fastest healing time.
– Castrated males are called geldings. They have physical and temperament differences from stallions.
– Geldings are calmer in mood, less muscular, and taller on average than stallions. Their neck shape is more feminine.
– Testosterone drops significantly after castration. Male sex drive is reduced but not entirely eliminated.
– Geldings can no longer reproduce since their testicles are removed. However, their penis and other reproductive anatomy remains intact.
Behavioral Differences
In addition to physical differences, the behavior of stallions and mares has distinct characteristics:
| Stallion Behavior | Mare Behavior |
|---|---|
| – More aggressive and competitive | – Less aggressive than stallions |
| – Herd hierarchy focused on accessing mares | – Herd hierarchy focused on care of foals |
| – Tend to be more territorial | – More social than stallions |
| – Driving off challengers and rivals | – Leading groups of mares and offspring |
| – Courting and mating with mares | – Mothering behaviors like nursing, grooming, and teaching foals |
Key differences in stallion and mare behavior stem from instincts related to mating and reproduction. However, training and environmental factors also play a significant role in any horse’s temperament.
Gender Identification
It’s important to be able to correctly identify the gender of horses for breeding management, veterinary care, competition rules, and proper horse handling. Here are some tips:
– Check for external male genitalia like the penis and scrotum in stallions/colts or the vulva and udder in mares/fillies.
– Look at neck thickness and shape. Stallions typically have thicker, more arched necks while mares have slender necks.
– Note differences in muscle development, especially in the shoulders, neck, and hindquarters. Stallions are more muscular.
– Observe urination posture. Stallions extend the penis while squatting down rather than urinating straight back under the tail like mares.
– Consider height, weight, and size. While ranges overlap, stallions tend to be taller and heavier.
– Review horse registration documents for listed sex. Breed associations verify gender at registration.
– Ask the horse owner, breeder, trainer or veterinarian directly about the sex of an unfamiliar horse.
Caring for Stallions and Mares
While all horses need proper care and handling, some considerations apply specifically to stallions and mares:
– Stallions require very secure, strong fencing to prevent escape and injury to other horses. Electric fencing may be recommended.
– Stallions often need to be housed singly and away from other horses, like geldings. Their paddocks should prevent contact.
– Experienced handlers should work with stallions. Their aggressive and mating behaviors can present risks.
– Mares nursing foals need adequate nutrition and space. Their foals should have access to feed, clean water, shelter, and room to run.
– Monitor pregnant mares for health issues like difficult labor requiring veterinary assistance. Have a foaling kit prepared.
– Wean fillies and colts appropriately, providing care that meets their developmental needs for proper growth.
– Make sure all horses, including mares and stallions, receive regular hoof, dental, and health care from equine professionals. Follow vaccination and deworming schedules.
Breeding Considerations
Responsible horse breeding requires careful planning, management, and safety protocols. Here are some best practices to follow:
– Select a quality, registered stallion and mare with excellent conformation and temperament from the same breed.
– Breed after a mare’s first heat of the season for the best conception rates. Track her cycle closely.
– Provide safety measures like a chain lead, twitch, and breeching strap when hand breeding stallions.
– Artificial insemination can be used instead of live cover and is safer. Semen is collected and inserted into the mare’s uterus.
– Follow up with ultrasound scans 14-16 days after breeding to confirm pregnancy. Repeat scans later to monitor fetal health.
– Make sure adequate staff and facilities are available to properly handle breeding, foaling, and aftercare.
– Keep detailed records on the sire, dam, breeding dates, pregnancy, and birth outcomes. Register foals promptly.
– Review horse breeding laws that may apply, like testing requirements or breeder licensing.
FAQs
Here are answers to some frequently asked questions about stallions and mares:
Can a stallion turn into a mare?
No, a stallion cannot turn into a mare. The male and female reproductive organs of horses develop differently in utero. Castration turns a stallion into a gelding, not a mare, by removing the testicles.
At what age can a stallion breed?
Stallions can start breeding by about 18-24 months of age once they go through puberty. However, extensive breeding is not recommended until maturity at 4-5 years old for the stallion’s health and quality semen production.
What is the best age to breed a mare?
Mares can be bred starting at about age 2 but most owners wait until at least 3-4 years old for the mare’s physical maturity. Many breeders prefer breeding maidens no earlier than 4 years old. Mares can produce foals well into their late teens or early 20s.
How often can you breed a mare?
A healthy mare can safely carry a foal about once per year during the breeding season. It’s ideal to give mares 1-2 breeding seasons off after producing several foals to allow their body to recover before the next pregnancy.
Can a mare be too old to breed?
Mares can usually conceive and carry a foal into their late teens or early 20s. The upper limit depends on her physical condition. Older pregnancies are considered higher risk so owners should consult their veterinarian. Genetic issues are also more likely in older mares.
Conclusion
In summary, horses display key physical and behavioral differences between stallions and mares. Stallions are male horses used for breeding while mares are the female horses that gestate and raise foals. Proper identification, handling, and care practices should be followed with both stallions and broodmares. Responsible breeding requires extensive planning and management for the wellbeing of the horses and offspring. While challenging, breeding horses can be a very rewarding experience done right.