Why 'seems fine today' doesn't mean your 15 kg dog is safe
Anticoagulant rodenticides work by preventing blood clotting, but this process takes time — clotting factors already in your dog's system must be used up before symptoms appear. A whole bait block contains enough poison to overwhelm a dog his size, even if he appears normal for now.
The first signs often resemble vague illness: less interest in food, tiring easily on walks, or sleeping more than usual. These subtle changes might happen before any visible bleeding, which is why waiting until you see blood means you've waited too long.
The critical 36-72 hour window after ingestion
Most dogs show symptoms between days 2-5 post-ingestion, but the exact timing depends on the specific anticoagulant (brodifacoum acts faster than warfarin) and your dog's metabolism. Larger amounts can accelerate the timeline, and a whole block constitutes a large dose for a 15 kg dog.
Internal bleeding often starts in the chest or abdomen, causing labored breathing or a distended belly before external signs appear. Nosebleeds or bloody stools typically come later, indicating significant clotting impairment.
What blood tests reveal before symptoms start
A clotting test called PT/PTT can detect poisoning 24-48 hours after ingestion, long before symptoms emerge. This is why vets recommend testing even asymptomatic dogs — catching it early allows vitamin K treatment to begin while clotting factors are still partially functional.
Without treatment, bleeding into joints or the brain can cause lameness or seizures days after exposure. These delayed effects make anticoagulant rodenticides particularly dangerous compared to poisons that cause immediate vomiting.
Why vitamin K must start before day 3
Vitamin K therapy works by helping the liver produce new clotting factors, but this takes time — starting treatment after bleeding begins is like trying to fill a bathtub with the drain open. The standard protocol involves weeks of oral vitamin K1 to outlast the poison's effects.
Your vet may also recommend hospitalization for plasma transfusions if clotting tests show severe impairment. The cost of prevention is always less than treating full-blown hemorrhage, both financially and for your dog's wellbeing.
The step-by-step response, from the first minute to the vet visit, is in our Anticoagulant Rodenticide Toxicity in Dogs and Cats emergency guide.