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What Are Bully Sticks?

| Updated October 19, 2017

After steers or bulls are slaughtered, virtually every part of the animal is put to use. While much of the flesh becomes different cuts of meat, the skin is used for leather products. The skeleton might be ground for bone meal. And the penis? That could become a bully stick, a Fido favorite.

Bully Sticks

In the past, the male bovine's penis didn't go to waste after slaughter. It might be ground down into medicinal drugs, used as a walking stick or consumed by some people. Today, the bully stick -- also called a "pizzle" stick -- is in demand as a dog treat. The penises are dried, then cut into various sizes for marketing. Some manufacturers use chlorine or other chemicals to remove the natural odor, but conscientious consumers don't want to feed treated bully sticks to their pets.

Cow Muscle

If you didn't realize that you were giving Fido sections of bull penis, you're probably not alone. According to a survey conducted in conjunction with a study by researchers from the University of Guelph and the "Cummings School of Veterinary Medicine at Tufts University," there's no law stating that manufacturers must list "bull penis" as the primary ingredient. In the study published in the January 2013 Canadian Veterinary Journal, researchers found that packages might refer to the contents as "cow muscle" or "bull pizzle," a term for penis used Down Under but not common elsewhere.

High in Calories

The study concluded that, based on the size of the bully stick, it might contain between 9 to 22 calories per inch. For a small dog, one bully stick comes close to one-third of daily caloric needs. For a weighing about 50 pounds, that's 9 percent of his daily calorie requirements. If your dog is overweight, think twice about giving him bully sticks. Ask your vet about a chew toy lower in calories, so your dog can enjoy the pleasure of chewing without the risk of weight gain.

High in Bacteria

Of the 26 bully sticks tested in the study, one contained Clostridium difficile, while another had evidence of the dreaded "Methicillin-resistant Staphylococcus aureus," better known as MRSA. That bacteria is resistant to many antibiotics. Seven bully sticks contained E. coli. One of the seven was a type of E. coli resistant to tetracycline. The researchers recommend that purchasers wash their hands after feeding the treats to dogs, and that those with immature or compromised immune systems avoid handling bully sticks.