Do Horses Have Udders? (Yes, But There’s More To It!)

What You Need to Know About Horse Udders

Almost everyone knows that cows have udders; on average, one person consumes an average of 600 lbs of milk, cheese, and other dairy products a year. but have you ever wondered whether horses have udders? Horses are similar to cows in many ways, but what about milk production?

Do horses have udders? Female horses have udders, though they are much smaller than the udders of a dairy cows. They contain two mammary glands, with one teat per gland. Horses generally only produce as much milk as their foals require; therefore, they are not “milked” by humans like cows and goats.

In this article, I explain everything you need to know about lactating mares, horse milk production, and horse milk uses. Keep reading!

How Much Milk Do Horses Produce?

Horses are not known to produce milk over what is needed for their foals. Horses produce approximately 2-4% of their body weight in milk during peak lactation, equaling approximately 3-6 gallons per day.

A Holstein cow, meanwhile, can produce up to 9 gallons of milk per day. This makes dairy efficiency a clear win for cows, especially considering cows generally require fewer calories and are easier to care for than horses.

Dairy goats, too, produce a high percentage of their body weight in milk during peak lactation, and though less than both horses and cows in sheer quantity, they are much easier and more efficient to keep than other livestock.

When Do Horses Start Producing Milk?

A mare’s udders will generally be very small and will not begin filling with milk until the end of her pregnancy, depending on whether the mare is a maiden. Mares on their first pregnancy may not produce any milk until their foal’s birth or shortly prior. Experienced broodmares may begin producing milk as early as thirty days before birth. A waxy substance may appear on the teats a few days before foaling. This waxy substance, along with changes to the vulva, can be appropriate indicators of impending labor.

Once a foal is born, he or she will begin nursing shortly after birth. The foal will nurse every few hours for the first few months. Many breeders will wean their foals between four and seven months; however, in the wild, they may not completely wean until eight to nine months of age. 

Feeding a Lactating Mare

A pregnant mare does not need additional calories until her last trimester. At this time, many breeders supplement with alfalfa and/or grain. Talk to your vet about how many additional calories to give your horse when in doubt. Overfeeding a pregnant mare is more commonly a problem than underfeeding. Like all horses, Mares rarely turn down extra calories, but obesity can have serious repercussions when it is time to foal.

During peak lactation in the first few months of her foal’s life, a mare’s nutritional requirements will increase even more. At this time, you should expect a mare to eat 1.5 to 1.7 times that of a non-pregnant mare. 

In addition to the extra calorie requirements, lactating mares should significantly increase their water intake by up to 75% of their non-lactating friends. Horses should always have access to fresh, clean water, which is especially important during lactation. 

Horse Udders: Potential Problems

Fortunately, horses rarely have udder problems, and this may be in part because they have not been bred to produce higher-than-natural quantities of milk like dairy livestock. Nevertheless, udder problems are not unheard of, with two of the most common being mastitis and agalactia.

Mastitis in Horses:

Mastitis is an infection of the mammary gland that can result in swelling and pain and cause severe fever and lameness in the hind limbs. Mastitis is most often a result of bacterial infection and is much more likely to occur when an excess of milk is trapped in the ducts.

Mastitis is most likely to occur during the first one to two weeks of weaning when the udders are still producing milk, but no nursing can relieve the pressure. While some people may want to express their horse’s mammary glands to ease the discomfort sudden weaning can cause, this will only prolong the problem.

Without expression, milk production will drop on its own. It can be helpful, when weaning, to keep the foal not only physically separate from the mother but also out of earshot or eyesight; this will aid the mare’s hormones in decreasing milk production.

Agalactia in Horses:

Agalactia is the lack of milk production when a foal is born. When this happens, supplemental colostrum and milk must be provided to the foal until the lactation problem is corrected. Agalactia is most often caused by the fungus Claviceps sp., found in many fescue grasses.

The fungus can also cause thickened fetal membranes, prolonged gestation, abortion, and premature placenta rupture. It is advised that pregnant mares be taken off of fescue grass during the last trimester of pregnancy. At this time, their diet can be supplemented with alfalfa. 

Other Udder Problems in Horses:

In addition to mastitis and agalactia, a few other udder concerns can pop up. 

  • Dripping milk – if a mare is “dripping milk” before foaling, this can lead to a lack of colostrum, and thus infection-fighting antibodies, for the foal. Call your vet if your mare is dripping milk during the late stages of pregnancy, as this may be a sign of a problem for both the mare and foal.
  • Early milk production – if a mare is filling up her udders earlier than a month before foaling, this can indicate a problem such as a placental infection or the presence of twin foals. A vet should be called out to assess the pregnancy.
  • Swelling in front of the udder – swelling in front of the mammary glands can indicate a collection of lymphatic fluid that can be difficult to drain during the late stages of pregnancy. This is usually not a problem and should be resolved shortly after foaling.
  • Lumps – tumors can be found in the mammary glands of horses, and a vet should examine any lump found around the udder.


Do People Drink Horse Milk?

Once you realize that horses produce milk and have udders like dairy livestock, you may wonder whether people milk horses the way they do cows. In some countries, particularly in Central Asia, people use fermented mare’s milk to produce alcoholic beverages. This is more of a delicacy than an efficient way of producing dairy products because of the quantity of mare’s milk compared to cow’s or goat’s milk.

Iceland and Mongolia are two countries that still incorporate horses into almost every part of their lives. While on different sides of the world, both these countries have a large horse population and cultures and traditions that rely heavily upon them. In these countries, horse products are used more frequently. Horses are used for transportation, farming, and, on rare occasions, for meat and milk. The people of these countries have a deep respect for the horses and the role they have played in their nations’ development. 

The Horse’s Heat & Breeding Cycles

The natural breeding season of a horse is between late Spring and early Fall. During this time, a mare will go into heat every three weeks. Each heat cycle will last between 2 and 14 days, depending on how far into the breeding season. On average, the mare will be receptive to the stallion for between 5 and 6 days.

Once a mare is in foal, she will gestate for approximately 11 months, or between 330 and 342 days, to be more precise. There can be a significant range for the gestation of a healthy pregnancy, though prolonged gestation can result from a fungal infection.

What Is An Udder?

All mammals have mammary glands, but this does not mean all mammals have udders. The definition of an udder, as provided by the Oxford Dictionary is: “the mammary gland of female cattle, sheep, goats, horses, and related animals, having two or more teats and hanging between the hind legs of the animal.” The udder is usually contained in one organ between the hind legs, with two to four teats. 

Not all milk-producing animals have udders. In humans and apes, the mammary glands are located on the chest and are referred to as breasts. One interesting fact about breasts is that elephants also have them! You wouldn’t have been alone if you assumed that elephants have udders. Elephants have two distinct breasts between the front legs that are only visible while lactating.

Horse Udders Are For Horse Babies

While cows and goats have been bred over centuries to provide ample high-quality milk for human consumption, this has not translated to horses. There are multiple reasons for this, but the most significant is that horses are much less efficient in keeping for milk production than other dairy livestock.

Still, horses are effective milk producers, creating enough milk to give their foals the best chance of thriving during their early and vulnerable months. After all, this is what horse udders are for: feeding horse babies.

Besides udders filling up, there are a few other ways to tell if your horse is pregnant. To learn more, visit my article Is Your Horse Pregnant? 8 Clear Signs to Tell.

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Carmella Abel, Pro Horse Trainer

Hi! I’m Carmella

My husband and I started Equine Helper to share what we’ve learned about owning and caring for horses. I’ve spent my whole life around horses, and I currently own a POA named Tucker. You can learn more here.

Thank you for reading, and happy trails!

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