Rat poison can often take you by surprise. It’s not the signs one would think of when thinking of a poisoning. Its effects are not immediate—and therein lies the danger. Unless you have seen your pet eating the poison, you may not even know they’ve had it. Effects can take from 5–10 days.
Rodents can also move poison. You may think you have put it in a place where your pet can’t reach it but it has been moved. Or neighbours may have put it out and rodents move it to your property. Some rodents may even have ingested the poison and have been eaten by your pets, which then have eaten it too.
Rat poisons are typically anticoagulants. They are very different to the common poisons used for malicious poisonings (for example Two Step).
The purpose of an anticoagulant is to prevent the clotting of blood. When eaten by an animal, anticoagulants block the production of Vitamin K, an essential component for normal blood clotting, which results in spontaneous and uncontrolled bleeding.
Dogs that have mild anticoagulant poisoning will not show signs of poisoning for several days, but as the poison begins to affect the system, the dog will become weak and pale due to blood loss. The bleeding may be external (nose bleed, bloody vomit, or bleeding from behind). Dogs can also suffer from unseen internal bleeding. This may not be obvious, which is why it is such a dangerous poison. Dogs may bleed into their chest or abdomen, which is fatal if it not diagnosed in time.
The most common symptoms of anticoagulant poisoning are:
- weak, wobbly, unstable;
- nose bleeds;
- blood in vomit or stools (though note that bloody stools/vomit can also be from other causes, like severe gastros);
- bleeding from the rectum;
- bruises and hematomas under the skin;
- bleeding in the gums;
- swelling of the abdomen due to accumulation of blood; and
- difficulty in breathing due to blood in the lungs.
Some of the main anticoagulant chemicals that can be found in rodent poisons are Warfarin, Hydroxycoumadin, Brodifacoum, Bromadiolone, Pindone, Diphacinone, Diphenadione, and Chlorohacinone.
The first kind of anticoagulants are cumulative poisons. These poisons contain Warfarin and Hydroxycoumadin as main anticoagulants, and they require multiple feedings, which take several days to kill a rodent.
The second type of anticoagulant is deadlier, killing rodents in a single serving rather than over time. These deadlier anticoagulant poisons contain Indanedione class products, like Pindone, Diphacinone, Diphenadione and Chlorohacinone, all of which are extremely toxic. Rodenticides that contain the ingredients Bromadiolone and Brodifacoum, for example, are 50–200 times more poisonous than the kind that contain Warfarin and Hydroxycoumadin.
Another cause of anticoagulant poisoning in dogs is the accidental ingestion of medication. Heparin, a common drug for treating blood clotting in humans, can have a toxic effect on animals.
To confirm rat poisoning, blood is taken to test clotting time. These tests are called PT and PTT. Blood in a normal animal will clot within a certain amount of time. Animals with a clotting deficiency will take longer or fail to clot.
If you have a sample of the poison, take it with to the vet. If you see your pet ingesting the poison, getting them to the vet to make them vomit immediately is ideal. However, if they are not brought in before the poison is digested from the stomach, it does not help to make them vomit. Do not induce vomiting unless you have been advised to do so by your veterinarian. Some poisons can cause more harm coming back through the oesophagus than they did going down.
Treatment will involve administering fresh whole blood if their blood count is very low. Vitamin K, which is necessary for normal blood clotting, will be given for several days, until the body is able to resume normal clotting.