Christine Legere’s article in the Dec. 30 edition of the Independent about Provincetown’s approach to rat control triggered many memories for me. Some were traumatic, like the memories of wild rat invasions of my chicken coop. I’m also a Norwegian fancy rat aficionado, with loving memories of some of the best pets I’ve ever had.
That article also triggered veterinary memories of combing through what a dog (usually a Labrador) has coughed up, hoping to find the bright green block of rat poison that the dog’s owner has just seen it eat.
Dogs ingest rodenticide in all seasons, but there seems to be an increase in the early spring, as people return from their winter places to their empty Cape Cod homes. Usually, the family dog is the first one into each room, including the basement, and will be the first to find that tasty morsel of rat poison placed there by the owner or a caretaker the previous fall. A surprising number of dogs also get into trouble eating poison on boats.
In the best-case scenario, the owner actually sees the dog scarf down the poison, the cardboard box with the product type and amount has been carefully saved, and the phone number of the ASPCA Pet Poison Hotline is in the owner’s cell phone address book.
When we know that the pet has ingested the product and have its name and the amount, our goal is to get it out as fast as possible by giving drugs to induce vomiting and comparing what comes out to what went in. Knowing with confidence that we have decontaminated the pet means it is at very low risk of complications.
Unfortunately, many times we know only the general color and size of the poison the dog just ate. This is when the Pet Poison Hotline is invaluable. Often, by asking the upset and scared owners the right questions, we can determine the type and amount of product ingested, then make a plan if we think the entire amount was not expelled.
The most frequent kind of rodenticide dogs accidentally ingest are the anticoagulant-based poisons, which cause death by disrupting clotting, leading to prolonged bleeding. Brodifacoum is a second-generation rodenticide that is available as an over-the-counter product, and is therefore frequently ingested.
When the poison has been digested, dogs are treated with Vitamin K, the antidote to the poison, as well as strict instructions to avoid roughhousing or vigorous activity. We measure the clotting time of the animal’s blood and often recheck it at the end of treatment as well. Without treatment, animals who have been exposed can present with spontaneous bleeding into the chest or abdomen, or profuse bruising without any known trauma, and are at risk of death. Depending on the severity, they may require plasma or blood transfusions, oxygen therapy, or blood clot therapy.
Cats go into the same column as wildlife here. It is rare for a cat to directly eat rodenticide. That’s lucky, because it is very difficult to induce vomiting in a cat no matter what fancy carpet you provide for them to puke on. If yours is an outdoor cat that feeds on rodents, however, it can suffer the effects of secondary rodenticide poisoning, because the poison remains in the liver tissue of the rodents for a long time. This is the same route of exposure that endangers birds of prey such as red-tailed and Cooper’s hawks.
The effects of using anticoagulant rodenticides are far-reaching. We know it causes suffering and death in wildlife that ingest prey targeted by the poison. We know that dogs eat really weird things and leaving out a block of rodenticide may kill your furry best friend instead of the rats you were aiming for.
Even if nontoxic options for rodent control fail, there are other alternatives, such as Vitamin D-based products that have not been found to affect wildlife the same way anticoagulant toxins do. A holistic approach would combine measures to avoid attracting unwanted rodents and, if needed, working with a professional pest control company that is knowledgeable about the most environmentally friendly approaches.
Sadie Hutchings is a veterinarian who lives in Wellfleet.