I have a mare that is allergic to anything you care to name and a few things you may not think of straight away. In the beginning, I used to think she was an exceptional case, a freak if you will. Experience has taught me since then that allergies are as common to horses as colds are to human beings. I have no idea whether all horse allergies have existed from time immemorial, or whether horses are developing new allergies all the time, like human beings discover new diseases all the time. I had never heard of AIDS till I was in my twenties, and swine flu and bird flu seemed to come into existence when I was in my forties. I was aware of just human flu until then.
I have not been able to confirm if Trigger, Roy Rogers’ horse, had any allergies. Nor do I have any definitive knowledge about any allergies suffered by Dale Evans’ Buttermilk and Man O’ War. The books are silent on allergies that may have plagued Seabiscuit and Exterminator. How did people treat their horses for allergies in the days before vaccinations were invented?
Horses allergic to vaccinations show varying symptoms. In some, the area around the injection site will swell. Other horses break out in hives. Some horses develop tender rocky lumps that seem to go on and on for weeks. I have known a lot of horses to go off food.
My mare belongs to the “been there, seen it all, suffered it all” classification.
It is advisable for owners of allergy-prone horses to get the veterinarian to inject their horses with an antihistamine just after the vaccination. I have also ascertained that the location of the vaccination injection plays a huge rule in the effectiveness of the vaccination and in any allergic reaction it may bring about.
With my super-allergic mare, injecting vaccine on both sides of the neck, with an antihistamine injection thrown in on one side of the neck, did not seem to work. Her neck swelled alarmingly, and became very tender. She couldn’t lower her head or graze. At such times I had to feed her with a feed net.
But I believe in prevention, not cure. After trying vaccinations in the hindquarters and antihistamine in the neck and failing to keep down the allergic reaction once again, I got my vet to try shots in the hindquarters followed by antihistamine in the same part. That finally helped, surprising me, my veterinarian and most of all, my mare. You could see she was missing something.
My experiences with my mare have taught me that the best way to administer vaccinations to the horse with pronounced allergy is to give shots in both hind quarter areas and follow up with split antihistamine shots very near to the sites of vaccination injections. At the worst, this will keep your horse able to bend its head, graze and eat feed, though your horse may have to bear some soreness. I have received positive feedback about this method from practically all of my horse owner friends to whom I made this proposal.
Be very alert, though, if your horse develops respiratory problems in the aftermath of vaccination with or without antihistamine. Your veterinarian may have more work to do.