Pet Columns, Office of Public Engagement, College of Veterinary Medicine at the University of Illinois at Urbana-Champaign

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Change of Season Brings Hazards for Pets

Pet Column for the week of August 29, 2005

Office of Public Engagement
2001 S. Lincoln Ave.
Urbana, Illinois 61802
Phone: 217/333-2907
Kim Marie Labak
Information Specialist

As people prepare for fall weather, it's important to take safety precautions when using pesticides, winterizing cars, and tending to yards and gardens--activities that all involve substances toxic to pets.

Colder weather leads rodents to seek refuge in our heated homes. The pesticides we use to combat rodents can be extremely harmful, even fatal, to our pets, according to Dr. Petra Volmer, toxicologist at the University of Illinois College of Veterinary Medicine.

Often pet owners do not know that their pet has ingested a rodenticide. Signs of a problem vary depending on the type of product. The three main types of rodenticides that pets commonly encounter are anticoagulant-based, which interfere with the body's ability to clot blood; cholecalciferol-based, which increases the calcium in the blood to toxic levels; and bromethalin-based, which is a neurotoxin that can cause permanent damage to the central nervous system.

Clinical manifestations of a rodenticide poisoning in a pet range from lethargy, depression, weakness or trembling, drunken walk (ataxia), abnormal eye movement, and paralysis to increased water intake and increased urination, bloody urine or a bloody nose, and gastrointestinal problems.

Many rodenticides are sold as turquoise-colored pellets. Dr. Volmer advises pet owners to contact a veterinarian or the ASPCA Animal Poison Control Center immediately if they recognize something like this in their pets stool or vomitus.

Dr. Volmer says, "Pelleted rodenticides may be mistaken by pets as treats. Even if you tuck that tray of rat poison pellets where you think pets cannot reach, a rodent may drag it out where pets can find it."

Dr. Volmer also points out that rat poison can be a hazard when moving into a new home. Previous tenants may have left rodenticides under, behind, or on top of cabinets and appliances where pets, especially cats, can find them. Always inspect new homes thoroughly for leftover poisons.

Because many people winterize their cars early, antifreeze is another toxin common in the fall. The main ingredient in many products is ethylene glycol, a substance whose toxicity increases dramatically when metabolized by the liver.

Early treatment is imperative for a pet that has ingested antifreeze, so it is important to recognize the first signs of poisoning that often go unnoticed: a pet may appear "drunk," weak, or wobbly, especially in the hind legs, may appear lethargic and very thirsty, and may urinate frequently.

After this first stage, it may appear that the animal has recovered, when in actuality, the ethylene glycol is being metabolized into its poisonous form. If the pet is not treated at this point, it will likely suffer serious, often fatal, kidney failure.

If you suspect antifreeze poisoning, take your pet to a veterinarian, who will perform a number of tests to help confirm exposure. The best course of action is using safer antifreeze products that contain propylene glycol rather than ethylene glycol.

Hazards of fall yard work include iron-based fertilizers, herbicides that contain lead arsenate, and mulch made from cocoa hulls, which, like chocolate, is toxic to pets. Compost and leaf piles can harbor molds and other fungi that produce toxic byproducts, so keep compost piles fenced or covered, and don't let leaf piles sit too long.

If you suspect your pet has ingested a questionable substance, call a veterinarian or ASPCA APCC immediately. If possible, have the package or label of the suspected poison in hand.

The American Society for the Prevention of Cruelty to Animals (ASPCA), an allied agency of the University of Illinois, runs a 24-hour hotline at 888-426-4435. The hotline is staffed by licensed veterinarians with specialized training in toxicology and maintains a database with the latest research and information on new toxic products and appropriate treatments. There is a $50 fee per case, which includes follow-up calls made to the hotline by both you and your veterinarian.

For more information about household toxins and your pet, contact your veterinarian or visit and click on "Animal Poison Control Center."