Rat Bait Poisoning in Dogs

Rat bait poisoning (or toxicity) is common in New Zealand dogs. Rat bait is commonly used by farmers, householders and owners of industrial properties to kill rats. Most rat baits are warfarin based or similar: they act by stopping the blood clotting cascade. Unfortunately they have the same affect in pets and in children.

Clinical signs of rat bait poisoning in dogs will vary. Occasionally a dog will present to the clinic in acute shock due to severe bleeding from the anti-clotting effect of the poison. Bleeding may occur into the body cavities (abdomen and chest). Less severely affected animals may come in weak and pale, sometimes with blood in their vomit or faeces, or bleeding from their nose or urinary tract.
Occasionally animals present lame in one or more legs, where they have bled into joint spaces. Other animals come in looking perfectly healthy, but the owner has observed a knocked over box of rat bait, or suspects one of several animals has consumed the poison but is unsure as to which one.

Diagnosis of rat bait is made via the clinical signs and a blood test to determine how fast the blood is clotting. Where an owner is unsure if the dog has eaten rat bait and we see the dog straight away, we will induce vomiting to reduce the absorption of the toxin and do a blood test 3 days later. If it is unsure when the animal may have eaten the toxin, we will do a blood test then. Where clinical signs are already evident, the antidote for this type of poisoning is Vitamin K, initially given as an injection then as an oral liquid. The liquid is continued for at least 3 weeks and then a blood test is performed to determine that blood clotting time is normal. In severe cases, a blood transfusion will be necessary to provide an immediate supply to clotting factors.

Rat bait poisoning can be difficult and expensive to treat. Avoidance is the best answer: baits should be laid in pet/child proof containers, and out of harm’s way. Unused bait should be locked away.