[Britster]

VIN News

Veterinarians are trying to discern whether roughly a dozen dogs testing positive for hypercalcemia and consuming the same high-end diet is merely coincidence or a problem with the pet food in question.

The reports have cropped up on the Veterinary Information Network (VIN), an online community for the profession and parent of the VIN News Service. In message board discussions, veterinarians have revealed cases of hypercalcemia secondary to vitamin D toxicosis occurring in dogs that eat a single brand of dry pet food: Blue Buffalo Wilderness Diet, chicken flavor. In each of the cases, veterinarians report that dogs’ conditions have improved after switching brands.

So far, nothing concrete has identified a causal relationship between the food and illnesses in dogs. The U.S. Food and Drug Administration (FDA), while reportedly alerted to adverse events tied to the food, has not prompted a recall, though the VIN News Service has been unable to reach officials with the regulatory agency directly.

Officials with Wilton, Conn.-based Blue Buffalo report that “tens of thousands of dollars” and hundreds of hours have been spent analyzing various batches of dog food, including samples from bags directly linked to specific cases of dogs testing positive for hypercalcemia and vitamin D toxicity.

Richard MacLean, vice president of business affairs, says one thing is certain: Test results thus far have shown nothing unusual about the product’s formulation; amounts of calcium and vitamin D, in particular, are within the company’s specifications and well below levels that might be considered toxic. The company’s focus has been on Blue Buffalo Wilderness Chicken Recipe, manufactured in April 2010 with a best-used-by date of July 2011. Vitamin D toxicity, or hypervitaminosis D, induces bone loss and abnormally high serum calcium levels, which could result in kidney stones and the calcification of organs like the heart and kidneys if left untreated.

“We really do take very seriously our commitment to providing health nutrition to pets,” MacLean says. “From the moment this issue came up, we are looking to find out if this is something we can do something about.”

Dr. Joy Mueller, a veterinarian in Santa Rosa, Calif., says the condition isn’t one that an owner will likely miss.

Recently, her two-year-old Australian shepherd became lethargic, releasing copious amounts of extremely dilute urine throughout her house and drinking large amounts of water. Heeding the red flags, she tested the dog’s blood and noted elevated calcium levels and a low platelet count. Hypercalcemia is often associated with kidney cancer and lymphoma.

Yet after ruling out possible problems with kidney function, Mueller turned to the Blue Buffalo Wilderness chicken and turkey flavored dry food that the dog had been eating for two weeks and changed brands.

The result was dramatic; the dog's condition improved within 24 hours.

Mueller came to the association between the food and her dog’s condition independently of the VIN discussions on the topic, though she did not test her dog for elevated levels of vitamin D and cannot be certain that toxic levels of it prompted the animal's illness. Still, she e-mailed the VIN News Service last Friday to spread the word about her findings to other veterinarians.

Reflecting on the turn of events, she says: “Vitamin D toxicosis was not my first thought. Various types of cancer including kidney cancer were the big rule outs. I wasn’t thinking food until I switched him.”