Dear Dr. Symm,
I have a healthy 10 yr old mare that I have dewormed with 1.87% Iveremectin. Afterwards, there were numerous white,
pointed end worms in her stool. Approximately 5 cm long x 4mm thick; some were smaller. I dewormed this horse again with
1.87% Ivermectin about 3 week later. Some more dead worms appeared in her stool a day after the deworming. It has been 2
weeks since the last deworming and the dead worms continue to appear in her stool at irregular intervals. I found another dead
worm in her stool this morning; yesterday her stool was clear of worms, two days ago I found 2 worms etc. There is no pattern. I
was under the impression that the Ivermectin would kill the adult worms, but not encysted larva. I accept the fact that hoses will
have worms and may never be entirely free of them, and that the Ivermectin may not have killed all of the adult worms. I do not
understand why I am finding dead adult worms 2 weeks after deworming. I have two other horses in seperate stalls and paddocks.
After deworming them, they do not have the same lingering dead worm situation as this mare. Any insight you may have into
this would be greatly appreciated. – Mike, submitted via Horsegazette.com
Dear Mike,
Parasites progress through different larval stages before they reach their adult stage which could take days to even
months. Depending on the species, larval stages can occur within the horse or in the environment, or both. Ivermectin provides a
good broad-spectrum parasite control, however, it does not kill all larval stages of parasites. As the larva sporadically reach the
adult stage within your mare, they are killed by the ivermectin, days to weeks after administration. Given that you see worms in
your mare’s feces, she likely has a larger worm burden than your other horses and possibly may be re-infecting herself.
Recommendations for deworming strategies can vary regionally so we recommend consulting with your local veterinarian for
their thoughts and possibly having a fecal exam done. - Dr. Symm
Dear Dr. Symm,
Hi there, I have had this question for a while now. I have been in love with this horse for years now, he’s 12 and a
registered paint. He happens to be bow-legged, but not extremely. A hat does this mean to his future? How can I prevent injuries
in the future? Anything else I should know about it. Thanks for your time. Sincerely, Sabrina, submitted via HorseGazette.com
Dear Sabrina,
Horses with angular limb deformities, or crooked legs, come in all different types. These conformational defects can
lead to functional problems as form almost always impacts function. From your description you should consult with a
veterinarian about this horse’s particular conformation and how it may lead to problems in the future, or not. Your veterinarian
may recommend radiographic examination to determine if there is any underlying damage or arthritic changes within the horse’s
joints. – Dr. Symm
Dear Dr. Symm,
Is it best to feed my horse first, then exercise? Or exercise, then feed? Thank you for your time, Donna, submitted via
HorseGazette.com.
Dear Donna,
Most people would agree that generally speaking, horses should not be fed within 1-2 hours of exercise. That being
said, some people will feel strongly rather it is before or after exercise, while in reality the answer to your question depends more
on your horse than what is written in a book or on some person’s opinion. You should make sure that your horse has free access
to clean water continuously and that you have a diet formulated to specifically meet your horse’s needs. A veterinarian can help
you get your hay analyzed and determine the amount of supplemental concentrate or grain your horse might need to meet their
needs. – Dr. Symm