We know that ivermectin can be very dangerous to certain breeds of dogs. Ivermectin prevents or kills parasites by causing neurological damage to the parasite, resulting in paralysis and death for the parasite. Dogs genetically sensitive to the medication have an anomaly that allows the ivermectin to pass the dog’s blood-brain barrier and into its central nervous system, which can be lethal for the animal.
However, have you ever stopped to consider that the ivermectin you use to treat your horses for parasites could be dangerous to dogs that eat horse manure? We know how dogs love horse manure. So in hindsight, it makes sense that ivermectin in horse manure could pose a danger… and here is one such story:
My American Pit Bull Terrier is at University of Florida Veterinarian School of Medicine right now being treated for Ivermectin poisoning. He had a sudden attack while on our walk. Signs were 1st slobbering/drooling (excessively) then diarrhea. I arrived at an animal clinic within 20 min where he then began vomiting and having seizures. Blood work showed elevation in Liver and Pancreas reading was 1256 He was given fluids and treated for what the Dr suspected was heat stroke after 6 hrs the Dr gave him Vit K injection. I then transferred him to Emergency Hospital for over night care where he was given more fluids and I was informed his temperature had risen significantly and at about 6am he was given charcoal. In the morning the Dr. recommended University of Florida.
So I left immediately for UF. He had been on his side laid out flat for about 20 hours and when i put him in my car I noticed he wagged his tail slightly. During the drive he did raise his head in an effort to be upright! Upon arrival at UF his heart rate was critical. Meds to stabilizes heart/monitored catheter and IV fluids. Next day prognosis Ivermectin poisoning via ingesting Daily Feed Through Wormer in horse manure and or ingesting left over grain/wormer in stalls at night!!!
I had NO IDEA the horse manure could be toxic. I remove feces from pastures everyday and of course the dogs ride in 4wheeler with me and once in a while I would catch them eating the manure. Its been 6 days now his organs show NO damage. He’s been taken off all support. He is eating and drinking and can stand to urinate. He can walk briefly then he starts to have tremors/shaking and wants to sit down. I’m hoping since everything has progressed for the better that eventually his Central Nervous System will recover enough so that he can have a normal life. Going to visit him today and possibly bring him home. I know that I’ll have to provide a lot of physical therapy so if anyone has any ideas I would great appreciate them.
Sorry to be so long winded but I hope through my experience another dog will not suffer and will have a chance to survive. Please tell anyone you know that has horses and uses daily wormers that the manure is toxic!
BTW the UF was absolutely wonderful!!! They let me stay in the Critical Care unit in the cage with my dog anytime I wanted. I was there off and on for 4 days and I never saw anything other than wonderful caring DR.s, students and techs!!! God Bless them all.
Thanks to Cindy in Florida for sharing her story! And thanks to the folks at the University of Florida Critical Care Unit! You rock!
So here’s the deal per Chris Bern, DVM: “The amount of ivermectin found in [horse] manure has actually been studied. It’s a pretty low concentration, so a dog has to eat a fair amount to become toxic, but it can happen. The half-life of ivermectin in horse and cow feces has been measured at as low as 11 hours and as long as 9 days. That means that it can take up to 9 days for half of the ivermectin to become inactivated, then up to another 9 days for half of the remaining amount, and so on. Realistically you can have measurable ivermectin in the manure for 1-2 weeks.
He concludes his comments with this: Don’t let your dog eat livestock manure.