Rodent bait is one of the most serious autumn poisonings for dogs and cats, because with most products a pet looks completely normal for three to five days and then starts bleeding internally. If there is any chance your pet ate bait, phone us the same day, or an open emergency hospital if we are shut.

Why the bait appears in October

Rats and mice move indoors when the nights turn cold and the food outside runs out. Around Brentwood and along the Hastings corridor that happens in October, and the response follows within days: bait stations go in beside garbage enclosures, in parkades, in crawl spaces and along fence lines.

This part of Burnaby has a specific set of conditions. Where there is construction and ground disturbance, rodents tend to move into neighbouring blocks, and Brentwood has had a good deal of both. There are townhouse complexes and apartment buildings where pest control is arranged by a strata or a property manager, so bait is placed without any individual resident being asked. And there are back lanes, shared garbage areas, green bins and bird feeders, which is the food supply that drew the rodents in the first place.

The result is that a dog walking the same route they have walked all year is now passing bait stations that were not there in September, and a cat who patrols a back lane is now hunting rodents that may have eaten bait.

Four kinds of bait, four different problems

This is the part worth understanding, because the products look similar and behave completely differently. Which one it is changes everything, and that is why we ask for the packaging rather than a description.

Anticoagulants are the most common. In British Columbia the ones you are most likely to meet are the first-generation products, warfarin, chlorophacinone and diphacinone, because the stronger second-generation actives such as brodifacoum and bromadiolone have been restricted here since 2023 to a short list of essential services. Older stock still turns up, which is another reason we want the box rather than a description. They stop blood clotting, and the effects are delayed. A dog who eats bait today will usually seem entirely normal for three to five days, and then begin bleeding internally. By the time there is a visible sign, the problem is well advanced. These are the ones that most often catch owners out, because nothing looks wrong at first.

Bromethalin affects the brain and causes swelling inside the skull. Signs can come on within hours to a couple of days: wobbliness, tremors, weakness in the back legs, seizures. There is no simple way to counter it, so getting the animal in early matters even more than usual.

Cholecalciferol is vitamin D3 at a concentration that raises blood calcium to a level that damages the kidneys. It takes very little, the effects build over a day or two, and these patients often need several days of care. Increased thirst and urination, vomiting and lethargy are the usual signs.

Zinc phosphide is used mostly for moles and gophers and produces a gas in the stomach. It can make the people around the animal unwell too, so if a pet who has eaten this vomits in a car, open the windows. These need to be handled in a ventilated space.

Many of the bright blue and green blocks and pellets look alike regardless of which chemical they contain, and manufacturers change formulations between seasons. The colour tells you nothing. The box tells us everything.

The ways pets actually get hold of it

• A dog finding a bait station. The black plastic boxes are tamper resistant, which is not the same as pet proof. A determined dog can get into one, and they are placed at ground level where dogs sniff.
• Rodents moving the bait. This is the one almost nobody anticipates. Rats and mice carry blocks and pellets away and cache them, which is how bait ends up behind a dryer, under a deck, in a planter or in the middle of a yard where no bait was ever placed.
• Bait placed loose. In a crawl space, a garage, a shed or behind an appliance, by a previous resident or by someone doing it themselves.
• Eating a poisoned rodent. Relay poisoning. The risk is lower than from eating the bait directly, but it is real, and it matters most for cats and small dogs. The anticoagulants are the ones that carry this risk, because they build up in the rodent’s liver; it is much less of a concern with bromethalin and has not been reported with cholecalciferol. A cat who catches a slow-moving rat in a lane where bait has been placed is a reason to phone us.
• Visiting somewhere else. A relative’s garage, a cabin, a rural property, a construction site on the walking route, a building parkade.
• Snap traps and glue boards. Not poison, but snap traps cause injuries to noses, paws and tongues, and glue boards cause considerable distress. Never put either where a pet can reach.

What to do if you suspect your pet ate bait

1. Phone us the same day, not when signs appear. With anticoagulants, by the time there are signs the window for straightforward help has closed. Early is the whole thing. If we are closed, including all day Thursday, phone the nearest open emergency hospital instead rather than waiting for us.
2. Bring the packaging, or a photograph of the label and the active ingredient panel. If it came from a bait station, the station itself usually has a label on the lid, and a property manager or pest control company can provide the product information.
3. Estimate the amount and the time. How many blocks or how much of a pouch, how long ago, and your pet’s weight.
4. Bag up anything left, including chewed fragments. If your pet has vomited, photograph it rather than transporting it, and if there is any chance the product was zinc phosphide, leave the vomit behind and keep the car windows down.
5. Do not make your pet vomit at home. Not with peroxide, not with salt, not with anything. With some of these products it makes things worse, and with an unsteady animal it is dangerous.
6. Give nothing from your own cabinet. Over-the-counter supplements are not a substitute and can give false reassurance.
7. Bring your pet, not just the information. Bloodwork and an examination are what tell us where we stand.

Come in through our urgent care. Our pet care services team can also bring your pet’s parasite cover up to date at the same visit. Our pet diagnostics team can check clotting function, calcium, kidney values and red blood cell counts, and with anticoagulants a repeat clotting check a few days later is often more informative than the first one. That staged follow-up is where our medical services team comes in, and it is the reason we would rather plan the week with you than see you on day five.

Our open days are Monday, Tuesday, Wednesday and Friday, 9:00 AM to 7:00 PM, plus Saturday and Sunday, 9:00 AM to 6:00 PM. Thursday we are shut all day, and so are statutory holidays. Bait does not work around that schedule. If your pet gets into some before nine, after closing, on a Thursday or over a holiday, drive to an emergency hospital that is open and let them know you are coming. A suspected bait case is never worth holding for our next open day.

What you might notice, by product

Because the four kinds behave differently, there is no single list. What to watch for, if you already know what was eaten:

• Anticoagulants: pale gums, weakness, exercise intolerance, coughing, laboured breathing, a swollen or painful belly, bruising, blood in urine or stool, bleeding from the nose or gums, lameness from bleeding into a joint. Typically three to five days after the event.
• Bromethalin: wobbliness, tremors, weakness in the hind legs, dullness, seizures. Hours to a couple of days.
• Cholecalciferol: increased thirst and urination, vomiting, loss of appetite, lethargy, weakness. One to three days.
• Zinc phosphide: vomiting, bloating, a garlic or fishy smell to the breath, difficulty breathing, collapse. Within hours.

Any of these, come in now rather than later. And if you do not know what was eaten but your dog or cat has unexplained pale gums, breathing difficulty, tremors or sudden weakness this month, mention rodent bait to us. It is one of the first things we will want to rule in or out.

What to ask your strata or property manager

This is the practical step most Brentwood residents can take, and almost nobody does.

• Ask whether rodent bait is currently placed on the property, and where. Common spots are garbage and recycling enclosures, parkades, mechanical rooms, landscaped beds and fence lines.
• Ask for the product name and the active ingredient, and keep it in your phone. If your pet ever gets into it, you will have the answer immediately.
• Ask to be notified before any new application, so you can keep your dog away from that part of the property for a few days.
• Ask for stations to be placed away from the dog walking routes and the areas residents use with pets.
• If you have a yard or a patio, ask that nothing is placed there without telling you.
• Raise the food supply as well. Overflowing garbage enclosures, unsecured green bins and bird feeders are why the rodents are there, and reducing those does more than bait.

Reducing the rodents without the risk

For your own property, the order that works is exclusion first, then sanitation, then traps, with bait as a last resort and only where a pet absolutely cannot reach it.

• Seal entry points: gaps around pipes, vents, dryer ducts, under decks, and the garage door seal. A mouse needs very little space.
• Keep garbage and compost closed, bring bird feeders in for the winter or move them well away from the house, and clear windfall fruit.
• Store pet food in sealed containers rather than open bags, including the bags in the garage.
• Use enclosed snap traps in places pets cannot access, inside a cupboard or behind an appliance panel.
• Avoid glue boards entirely in a household with pets.
• If you use a professional, tell them you have pets and ask specifically where product will be placed and what it is.
• While pest control work is being done, the simplest option is often to keep your pet off the property for a few days, with family or at a boarding facility, and to keep your dog’s walking route away from the areas that were done when you come back.

One more thought for the dogs who make a habit of eating things they should not. If yours routinely picks up and swallows objects on walks, the bait season makes that habit considerably riskier, and it is worth addressing properly. Our guide on socks, rocks and elastics, and why some pets eat things they should not covers why it happens and what helps.

Frequently asked questions

My dog ate rodent bait but seems completely fine. Can I wait and see?

No, please phone us today. With the most common kind of bait, a normal-looking dog on day one is exactly what we expect, and the bleeding starts three to five days later. Acting on day one is simple. Acting on day five is a different and far more serious situation.

How much bait is dangerous?

It depends entirely on which chemical it is and on your pet’s weight, and for some of these products the amount is very small. That is why we ask for the packaging rather than an estimate of size. Do not try to work out whether it was enough. Phone us with the label.

My cat caught a rat in the lane where the building put bait down. Is that a problem?

It can be. Eating a poisoned rodent carries a lower risk than eating the bait directly, but it is a genuine route, particularly in cats and small dogs, and it is the anticoagulants that carry it because they accumulate in the rodent’s liver. Phone us, tell us what bait the building uses if you know, and we will advise.

Are the black plastic bait stations safe around dogs?

No. They are tamper resistant, which is a real improvement, but tamper resistant is not pet proof. Dogs do get into them, and rodents carry bait out of them and leave it elsewhere. Keep your dog on a short leash past them and do not assume a sealed station means a sealed problem.

Can I give my dog anything at home if I think he ate bait?

Please give nothing from your own cabinet. Whether anything like that is appropriate, in what form and for how long, depends on which product was eaten and on blood results, and the versions sold for people are not the same thing. Phone us and let the veterinary team work it out.

The bait was eaten a week ago and my pet is fine. Are we clear?

Possibly, but phone us anyway and tell us the timeline, because the answer depends on the product. With anticoagulants, a clotting check at the right point after the event is the way to know rather than assume, and the right point is something we can work out from the date.

Is there a bait that is safe to use around pets?

No rodent bait is safe around pets, which is why exclusion, sanitation and enclosed traps come first. If bait is genuinely necessary, it belongs somewhere a pet physically cannot reach, placed by someone who knows you have animals, with the product name written down.

Speak to the team at Brentwood Animal Hospital

If your dog or cat has eaten rodent bait, or has caught a rodent where bait has been used, phone us with the packaging in front of you and we will tell you what happens next. Before we open at 9:00 AM, after we close, on Thursdays and on statutory holidays, go to the nearest open emergency hospital and call them on the way.

Published by the team at Brentwood Animal Hospital.

This article is for general educational purposes only and is not a substitute for an in-person veterinary examination or advice about your individual pet. If you have an urgent concern about your pet, contact Brentwood Animal Hospital or your nearest emergency veterinary hospital right away.

Brentwood Animal Hospital
4489 Hastings Street, Burnaby, BC V5C 0L6
Phone: (604) 900-8383
Email: info@brentwoodvet.ca
Hours: Monday, Tuesday, Wednesday and Friday 9:00 AM to 7:00 PM; Saturday and Sunday 9:00 AM to 6:00 PM; Thursday and statutory holidays closed