Shedding and spring – two words that go together in the Northeast. Although different horses shed at different rates and times, generally, by March most horses are well into the act of shedding. Why do horses shed their coats and what causes this to happen during spring?
As the hours of daylight increase during this time of year, the receptors in the horse’s eyes transmit messages to the brain to produce less of the hormone melatonin, causing the body to produce more prolactin, a hormone that controls hair growth. The prolactin found in the hair follicles controls whether the hair grows, as in autumn, sheds out, as in spring, or enters a resting phase, as during the rest of the year.
Although it is the amount of daylight that causes these changes in horses that trigger whether or not they shed, the horse’s skin temperature also plays a role in the hair growth process. For many who show their horses during winter, common practices that are used effectively include blanketing and/or heated stabling in addition to having their horses exposed to extra hours of illumination. These help prevent the growth of a full winter hair coat in autumn.
The hair coat changes with the seasons; therefore, its ability to regulate body temperature is related to its length, thickness and the density of hair per square inch of skin surface area.
The horse’s skin is actually an organ, and is the largest, averaging almost one inch in thickness – but it varies from as thin as less than one-half inch on the head, legs and underbelly to as thick as 1.5 inches over the lower back and rump. It’s important to remember this when grooming, especially the type of vigorous grooming that goes along with getting rid of all that loose hair, as you don’t want to cause your horse any discomfort during this important part of its care.
And not all horses react the same way to being groomed. Some seem to be much more sensitive about being brushed. When you think of how a horse can feel a tiny fly landing on its skin, you realize how sensitive an organ the skin is! Yet some horses, like my very first old gelding, loved to be brushed as strenuously as my 14-year-old muscles could muster. But “old habits” are difficult to forego, as I learned years later when shedding out and brushing my Thoroughbred, who would regularly “remind me” with ears back or even a raised foot when I was not gentle enough with the body brush, much less a shedding blade.
Horses can shed out at different rates even when they are stabled in the same conditions together. Mares tend to begin shedding first, due to the changes in their hormones that are associated with their reproductive cycles. When they are “in season” they begin shedding earlier. Non-cycling horses, such as geldings and stallions, will begin to shed later than mares. Aged or elder horses are the last to begin shedding.
Shedding and grooming in spring can be a messy business! Remember that the horse’s skin is thicker on the lower back and rump area and thinner around the head and legs; each horse will have a different tolerance to vigorous brushing. Photo by Judy Van Put
In our experiences, we would find that our mares would often have first loose hairs beginning to come out in early January, while the Thoroughbred and grade gelding would often not begin to shed until March 1. And our aged horses would generally be the last to lose their hair.
In fact, one of our elder horses, Sabrina, suffered from Cushing’s disease when we first got her – a condition that comes from tumors of the pituitary gland that can cause horses to have excessively long, sometimes curly and even matted hair up to four or five inches in length that rarely sheds out fully. Until we treated her for this condition, she was only successful in loosening up and shedding the hair on her face and limited areas of her body. The rest of her body would hold on to the thick, shaggy and curly coat she had grown as a result. Each year I would shed her out as best I could, and once it became warm enough, I would use clippers to finish removing the longest hair.
In addition to the gender of the horse, other factors that will affect shedding include its breed, age and its health and overall condition.
Draft breeds and “cold” horses have thicker coats and will shed more dramatically; “hot” horses such as Thoroughbreds and Arabians have thinner coats and shed a lesser amount than their “cold-blood” counterparts.
As mentioned, aged horses will shed later, and often will grow a heavier winter coat as well. But yearling horses will typically shed less hair and less dramatically than adult horses. A yearling’s first coat may be thicker than their later coats as they mature. It may also take longer for yearlings to shed out completely. They seem to retain their winter coat longer than adult horses, as their bodies are still growing and developing. Even their haircoat may not be as fully mature as that of an adult horse.
Lastly, your horse’s coat and its shedding habits are good indicators of their health and overall condition. Horses that exhibit excessive itching, rubbing and hair loss may be suffering from a number of conditions. A dull or brittle haircoat might indicate nutritional deficiencies. Horses need a balanced diet that includes the proper amount of protein, fat, vitamins A, C and E, copper, iodine and zinc for a healthy coat. An overload of parasites can also be the reason for a dull coat, as the parasites will be absorbing the nutrients that the horse is being fed. Fortunately, you can collect fecal samples and have them analyzed for parasites via a fecal egg count to determine if your horse needs de-worming.
Some illnesses that occur with a high fever or infectious disease may also cause a problem with your horse’s haircoat, and even hair loss. If your horse suffers from excessive itchiness or a brittle or dull coat, be sure to check with your veterinarian to determine the cause.
Happy spring, and have fun shedding!
by Judy Van Put
Leave A Comment