The start of winter tells your horse to start shedding!
This doesn’t make much sense…at first. In the US, we define the start of winter as the 21st of December. Around that time, and sometimes on the 21st itself, we have the winter solstice. This is the day where we have maximum darkness and minimum daylight. The day after the solstice is when the days start to get longer….with more light. In the summer, the longest day of the year happens around June 21st. The summer solstice is the day in which there is minimum darkness and maximum light.
Both days trigger your horse to start shedding!
It’s a complicated process, and it’s also a gradual one, which is why horses take time to shed out, we just don’t arrive to the barn one day and see a pile of hair and a sleek coated horse. Initially, your horse’s eyes start this process. His eyes tell his pineal gland to make some hormones, which then work on the pituitary gland to make more hormones. This second batch of hormones works on the thyroid gland – which is ultimately responsible for telling your horse’s body to release the coat he has and grow a new one. That’s a lot of steps… Some horse owners might start to see the winter coat shedding out in mid January, and the summer coat shedding out in mid August. Of course every horse will be on his own schedule, and the shedding process will be complete on their own time. You may also know that some metabolic disorders in horses, such as PPID (Cushing’s Disease) interfere with the shedding and hair growth process. This specific metabolic condition affects the pituitary gland, and as a result many horses with PPID are extra hairy all year long.
Once you see the shedding process starting, there’s no changing it, unless the amount of light changes. This can happen if you move your horse from the deep south to Canada, or vice versa, or if you move to a barn that keeps the stall lights on. Eventually your horse’s body will figure it out! In the meantime, keep currying with your grooming gloves, and happy bonding with your horse!