The truth about pet foods and rendering

Patty Khuly, DVM
Vet Reviewed
By Patty Khuly, DVM on Oct. 26, 2010
The truth about pet foods and rendering

Urban legends are one thing. The fact that the FDA seriously studied the levels and origins and clinical significance of barbiturates in pet foods fifteen years ago is quite another. Slow to the party, I’ve only just come to appreciate the veracity of all those presumptive urban legends about pets, rendering plants, and pet food.

Sure, I figured. There are bad actors at the margins of every industry. So I always believed in the salacious rumors. As in: Dr. X  and Shelter Y in backwoods Z sell surgically extracted gonads and dead pets to the local rendering plant for inclusion in pet foods! Is your pet eating ovaries, testicles, and drug-tainted dead pets?

It probably happens, I figured. I just never took it too seriously as a pervasive issue. Yet over the years it’s been a significant enough issue for the FDA to think it a worthwhile area of study with respect to barbiturates.

And here, included in a 2004  report to Congress on the rendering industry, is how it happens at the level of the independent rendering plant:

These plants (estimated by NRA at 165 in the United States and Canada) usually collect material from other sites using specially designed trucks. They pick up and process fat and bone trimmings, inedible meat scraps, blood, feathers, and dead animals from meat and poultry slaughterhouses and processors (usually smaller ones without their own rendering operations), farms, ranches, feedlots, animal shelters, restaurants, butchers, and markets. As a result, the majority of independents are likely to be handling "mixed species." Almost all of the resulting ingredients are destined for nonhuman consumption (e.g., animal feeds, industrial products). The U.S. Food and Drug Administration (FDA) regulates animal feed ingredients, but its continuous presence in rendering plants, or in feed mills that buy rendered ingredients, is not a legal requirement.

(My bolding, btw.)

So how has this continued to pass under our radar? Those generic, unspecified proteins and fats included in your pet's food? They may well —  legally — include canine and feline bodies. This may seem shocking to us in 2010, but this is business as ususal for the rendering industry.

If it’s always been done, why wring our hands over it now?

There are several reasons:

  • As a society, we no longer think it’s acceptable for our pets to eat other pets (especially of the same species). Our animal companions are too close to us, emotionally, to consider them cannibalistic.
  • Then there’s this emergent view: Those poor shelter animals! After what we’ve done to them, this is just pure insult.
  • Two words: "Mad cow." We now understand that some disease transmission is possible via rendered animal protein, heavily processed though it may be.

Back to the barbiturates:

Ten or so years ago there was this nagging question in companion animal veterinary medicine: Why do our barbiturates (back then employed as often for anesthesia or sedation as for euthanasia) seem to be losing their punch?

Then came a slew of articles about destroyed shelter pets getting tossed into the rendering plant and ending up in pet foods. The dirty secret was out of the bag. Yes, some shelters were all too happy to save money by having the carcasses carted off instead of having the expense of incinerating the animal remains. Never mind that most shelter pets were being euthanized via lethal injection using a barbiturate.

Which is when the vet community put two and two together and formed a hypothesis: that pets ingesting low levels of barbiturates in pet foods over a prolonged period of time might actually become resistant to these drugs. Could that be the answer to the diminished potency of barbiturates?

Though it was only an anecdotal finding, this diminishing drug potency issue, the FDA thought it merited a significant look-see, so they devised an experiment to 1) find out how much barbiturate was in pet food, and 2) whether dog and cat carcasses were actually comprising a significant percentage of what ends up in pet food.

Here’s what the report concluded:

The scientists purchased dog food as part of two surveys, one in 1998 and the second in 2000. They found some samples contained pentobarbital...

Because pentobarbital is used to euthanize dogs and cats at animal shelters, finding pentobarbital in rendered feed ingredients could suggest that the pets were rendered and used in pet food.

CVM scientists, as part of their investigation, developed a test to detect dog and cat DNA in the protein of the dog food. All samples from the most recent dog food survey (2000) that tested positive for pentobarbital, as well as a subset of samples that tested negative, were examined for the presence of remains derived from dogs or cats. The results demonstrated a complete absence of material that would have been derived from euthanized dogs or cats. The sensitivity of this method is 0.005% on a weight/weight basis; that is, the method can detect a minimum of 5 pounds of rendered remains in 50 tons of finished feed. Presently, it is assumed that the pentobarbital residues are entering pet foods from euthanized, rendered cattle or even horses.

For starters, I've never heard of a cow being euthanized via barbiturate — except one downer cow in vet school that was later used for anatomy class. The large quantities of barbiturates required make it an expensive and impractical option for cattle — especially for those destined to enter the pet food supply. Same goes for horses. Because, if you’ll recall, we used to slaughter horses in the U.S. So why would you sell your beloved horse to a rendering plant after the expense of a private veterinary euthanasia?

I’m not saying the FDA’s findings are wrong, just highly suspect in their ultimate conclusions. Something here doesn’t quite add up. As if the FDA is working a little too hard to talk us animal-activist busybodies down off this uncomfortable ledge we've collectively perched ourselves on.

Yet ultimately, this issue isn’t about whether there’s at least five pounds of protein in 50 tons of feed. Nor is it that the levels of barbiturates, as the FDA explains, are insufficient to render a drug less potent. Rather, it’s about the fact that any pet remains might be in our pets’ food. And that, the FDA concedes, is not up for discussion. This we already know.

Dr. Patty Khuly

Pic of the day: "Scared cat is really scared" by dat'

Patty Khuly, DVM
Vet Reviewed


Patty Khuly, DVM


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