The temperatures are dropping. Winter is approaching. Our horses are growing their winter coats. We are aware of the seasons, but we really don’t think about the effects they have on our horses.
Because the seasons change, the metabolism of our horses is altered. This occurs in a number of ways.
◆︎ Coat changes
During the winter months, horses will grow a winter coat. This is far thicker than the summer coat. When the horse gets extra cold, the hair stands on end, which traps air in between the hairs, adding extra warmth.
◆︎ Heat production
In addition to coat changes, horses utilize more energy to create sufficient heat to keep warm in the winter. This energy comes from extra stored body fat, or through an increase in caloric intake. It’s not unusual for horses to need a couple of extra flakes in the winter to maintain body condition.
◆︎ Reproduction
Mares have a gestation period of 11 months. It’s important that the mare foals in early spring or summer. This allows plenty of time for the foal to grow before the cold weather sets in. In the colder climates, if a mare has her foal outdoors in the snow, the foal may not survive and the mare may not have enough body condition to survive the rest of the winter. Because of this, most mares stop cycling at the end of summer. It is thought that the pituitary and ovarian signaling becomes uncoupled for this to occur.
Some mares experience fluctuations in insulin levels when they cycle.
◆︎ Insulin regulation
Elevated insulin levels are frequently associated with laminitis. Recent studies have shown that “normal” horses have two periods of time with significant changes in basal insulin levels. This occurs in the spring and in the fall. This creates two critical times of year to be extra vigilant if your horse is insulin resistant. The studies show:
➡ Normal horses (without insulin resistance and without PPID) may have elevated insulin levels in the fall.
➡ Horses with PPID (both treated with pergolide and those not treated) can independently have elevated insulin levels in the fall.
➡ Horses with high insulin levels may have those insulin levels climb even higher in the fall.
Caution is advised in the fall because of this rise in insulin that is independent of other factors.
◆︎ PPID – elevated ACTH levels
Studies have also shown that ACTH levels rise in the fall. For young horses and horses without PPID, this elevation is not problematic.
However, as the horses age, the ACTH level climb higher and remains elevated longer. As the PPID progresses:
♠ Coat changes occur.
♠ The horse may lose fat layers and muscling along the spine.
♠ The horse may act as though he/she doesn’t feel well.
♠ The horse may become more susceptible to infections.
♠ Increased thirst and urination may occur.
♠ Some horses may present with laminitis.
◆︎ Action points for owners:
➡ Warmth: Be sure that the horse is sufficiently warm for the weather. In very cold weather, older horses may need to be blanketed. However, it’s important to be aware that when daytime temperatures rise, the horse can become overheated with a heavy blanket.
➡ Food: Caloric needs are elevated in the winter. While it’s important to increase the calories, it’s also important to be aware that insulin levels may rise in the fall. A diet that is low in sugar and starch is more important during the periods of the year that the horse has seasonal fluctuations in insulin. A horse that may be well-maintained during the spring and summer might have an insulin rise that creates foot-soreness or laminitis.
➡ PPID: Be aware that the levels of pergolide that are suitable in the spring or summer, may not be adequate in the fall. It’s important to work with your vet to determine a suitable dose for your horse. It’s not unusual for a horse to need twice the amount of pergolide during the seasonal rise to maintain endocrine control. The goal is to avoid laminitis.
◆︎ Take home message:
You may need to modify the steps taken for the care for your horse because of the hormonal changes that occur in the fall.
We do the best we can for our horses. Being aware of the changes in the fall is a part of that.
Disclaimer: Statements regarding dietary supplements have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease or health condition.
©Joan Kulifay 2024