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Dr. Michael Fox, Published April 18 2014

Pet care: Certain dog breeds may have adverse drug reactions

Dear Dr. Fox: I have just adopted a 6-month-old female Australian shepherd mix from an adoption network. A friend warned me that this breed can get ill and die from heartworm prevention medication.

I respect his advice – he is a dog trainer and seems to know a lot. What is your opinion?

– K.P., Silver Spring, Md.

Dear K.P.: First, let me say that I now endorse year-round heartworm preventive medication for most dogs.

Your dog should also get periodic blood tests to check for heartworms because of climate change, traveling and the fact that more than 70 species of mosquitoes can transmit this disease. Your veterinarian can determine if it is safe to temporarily stop the monthly medication during the winter season.

You raise an important issue, which needs to be addressed. I hope all readers with dogs will take note because dogs do have adverse drug reactions, and many drugs are now being prescribed for the dogs’ entire lives.

Washington State University’s College of Veterinary Medicine advises, “Many herding breed dogs have a genetic predisposition to adverse drug reactions involving over a dozen different drugs.

The most serious adverse drug reactions involve several antiparasitic agents (ivermectin, milbemycin and related drugs), the antidiarrheal agent loperamide (Imodium), and several anticancer drugs (vincristine, doxorubicin, others).

These drug sensitivities result from a mutation in the multi-drug resistance (MDR1) gene.

At Washington State University’s College of Veterinary Medicine you can test your dog for multi-drug sensitivity and prevent serious adverse drug reactions. We can work with your dog’s veterinarian to find appropriate drug doses or alternative drugs for your dog based on results of MDR1 testing.”

Consult with your veterinarian about this genetic blood test, also available from other laboratories.

The university also posted the following breed prevalence as an approximate percentage frequency of the genetic mutation causing multidrug sensitivity: Australian shepherd, 50 percent; mini Australian shepherd, 50 percent; border collie, 5 percent; Collie, 70 percent; English shepherd, 15 percent; German shepherd, 10 percent; herding breed cross 10 percent; long-haired whippet, 65 percent; McNab, 30 percent; mixed breed, 5 percent; old English sheepdog, 5 percent; Shetland sheepdog, 15 percent; silken windhound, 30 percent.

As advances are made in canine genetics and related nutrigenomics – specific dietary requirements related to genetic background – the burden of disorders and suffering related to our selective breeding of various kinds of dogs may be alleviated, and our canine companions can enjoy a better quality of life in future generations.

Overall, mongrels – mixed breeds, not the new “designer” breeds – have the best prognosis.

Dear Dr. Fox: I would like to hear your rationale as to the difference between horse slaughter for human consumption, which you discussed in a recent column, and that of cattle, hogs, poultry and fish?

– B.W., St Louis

Dear B.W: My “rationale” is quite simple: While killing is killing regardless of the species, there is a difference in slaughtering animals raised or caught specifically for human consumption and those such as horses and dogs, which have enjoyed a close human bond.

This difference is cultural and, some would argue, also ethical. It is a kind of emotional betrayal of the animals’ devotion and service. There is also a biological difference – horses have not been selectively bred to be less reactive to being herded and transported, unlike cattle and pigs. I have visited livestock slaughtering facilities across the United States as well as in India and Africa and documented my concerns several years ago.

For an in-depth and in-field account of the continuing horrors in the meat industry, which would mean an intensification of this holocaust of the animals if horse slaughter were to become legal in the U.S., read the book by my friend and former co-worker Gail A. Eisnitz, “Slaughterhouse: The Shocking Story of Greed, Neglect and Inhumane Treatment Inside the U.S. Meat Industry.”

Pro-Pet food recall

Pro-Pet LLC of St. Mary’s, Ohio, has initiated a voluntary recall of a limited number of its dry dog and cat foods for possible salmonella contamination. Affected foods include Hubbard Life Happy Hound Dog Food, QC Plus Adult Dog Food and Joy Combo Cat Food.

For more information on the recall, including batch numbers, visit DrFoxVet.com and contact Pro-Pet’s customer service line at (888) 765-4190.


Send all mail to animaldocfox@gmail.com or to Dr. Michael Fox in care of Universal Uclick, 1130 Walnut St., Kansas City, MO 64106. The volume of mail received prohibits personal replies, but questions and comments of general interest will be discussed in future columns. Visit Dr. Fox’s website at DrFoxVet.com.