As I worked this weekend I was paged by a client who had five horses that potentially ate vole poison. The exposure occurred as the owner was applying it to one of their fields. He had the poison in the back of the Gator, in a container with a lid on it. The horses walked up, took the lid off and helped themselves to what they thought was a harmless snack. This particular poison was a relative of warfarin. Warfarin is a chemical that blocks the body’s ability to clot and subsequently causes uncontrollable bleeding. Death occurs due to blood loss.
This situation illustrates the importance of keeping all poisons out of the reach of your pets. No matter how careful you are these poisons are palatable because the target species must eat them. Non-target species (such pets, livestock, and wildlife) will therefore seek them out, and if they consume enough can be deadly.
The toxicity of all Warfarin type poisons are not equal. When Warfarin was first developed nearly every species were susceptible but it required exposure over a period of a few days and the toxicity was short lived. Over time however, rats became resistant to the effects of the toxin. Because of this resistance a “second generation” of poisons have been developed that can kill with one bite and they have a very long duration of activity.
Toxic ingestions are treated by causing the patient to throw up if they are dogs or cats, and then administering activated charcoal to bind any of the toxin that was still in the intestinal tract. In the case of cows or horses, which can’t be made to vomit, activated charcoal is administered via a stomach tube. Vitamin K (which is the antidote) are administered to counteract the effects of any toxin that may have been absorbed. If a second generation Warfarin is ingested the patient will need administration of vitamin K1 for six weeks due to its long duration of activity.
If your pet ate one of these rat poisons and you were unlucky enough to have not witnessed it, it will be at least 48 hours until you see any clinical signs. After 48 hours your pet will begin bleeding into the chest cavity. They will appear lethargic, may have pale membranes, and will be breathing hard. Treatment is much more difficult at this stage. They must be handled very carefully and a transfusion will be needed until the vitamin K1 has a chance to take effect which will be in 48 hours after administration.
The good news is that the horses I treated are doing well. With the quick reaction of the owners, who called right away, I was able to administer the proper treatment and circumvented these patients suffering any ill effects of the poison.
If you have any suspicion that one of your animals has eaten either one of these rat poisons contact your veterinarian immediately. Quick action can save their lives and prevent a great deal of heartache, suffering, and expense.