Features August 2003 Issue

Commercially Produced Recreational Chew Bones

What you should know about your dog’s recreational chew bones.

By C.C. Holland

With the third twist of the vise handle, the bone held snugly inside splintered along its length with a sickening crunch. Splinters and fragments sprouted from the crack like thistle.

The scene of a gruesome torture chamber? Hardly. Rather, this was a common result during informal testing conducted by WDJ in an attempt to ascertain whether certain types of “recreational” bones pose more hazards than others to the dogs who chew them.

This is a small (six-pound) dog with a big bone. Even so, he’s putting all his effort into trying to get some corner of the bone between his back teeth. This is how many dogs crack their molars. He does much better with a bone that is still covered with tissue, but he’s not a good candidate for recreational chewing with a dry bone.

First, some background. Our plan was to create a companion piece to an article about rawhide chews that ran in our May 2002 issue. We decided to take a look at the wide variety of commercially prepared bones available to dog owners in pet supply stores and catalogs. We hoped to learn whether these bones originated from U.S. livestock (which tends to be better safeguarded and regulated than animal products from some foreign sources) and what sorts of chemicals – if any – were commonly used in the preparation or preservation of the products. On both these counts, we heard good news.

Production methods
All the manufacturers whose representatives were willing to be interviewed told us that their companies obtain raw products from American slaughterhouses, and some (such as Abbyland Foods) get bones from their own slaughtering plants. Bones either were received frozen and thawed for processing or were processed fresh.

Production techniques were similar among the four companies whose representatives we interviewed, including Merrick Pet Foods in Texas; Redbarn in California; Abbyland Foods in Wisconsin; MI Industries (Nature’s Variety) in Nebraska; and Jones Natural Chews in Illinois. (Gimborn Pet Specialties in Atlanta, which sells bones through the Petsmart chain, declined our requests for an interview.) In all cases, creating the final product pretty much consists of simply cleaning and drying the bones in industrial ovens.

Some companies go the extra mile to ensure a quality product. Nature’s Variety – the only one of these companies that also sells frozen raw bones – prides itself on strict adherence to food-safety guidelines.

“We work in very close cooperation with the University of Nebraska food processing center,” says company president Bob Milligan. “They help us with processing techniques, selecting oven temperatures, testing for bacteria, and upgrading sanitation methods, things like that.”

Creating the cooked bones is a no-frills process. “We slow-roast them and then dry them down to a moisture content of approximately 10 to 12 percent,” says Milligan. “That allows them to be shelf-stable without having to add any preservatives, chemicals, or artificial colors. Our opinion, and that of our nutritionists and vets we work with, is that the product doesn’t need to have a smoked flavor to be appealing to the dog. And many times smoking is used to cover up an ‘off’ odor or condition.”

Other companies choose to add flavoring to the bones, either for marketing appeal or, in some cases, to prevent mold.

“We dip them in a solution of liquid smoke, for smell, and a marinate solution that helps inhibit mold growth,” says Jane Langman of Abbyland, which sells bones through Drs. Foster & Smith. “It’s an all-natural product – there are no preservatives.”

Most of these recreational bone manufacturers say preservatives are not necessary for bone products.

“Typically, with products under 10 percent moisture, there’s no need for preservatives,” explains Garth Merrick, president of Merrick Pet Foods. “Lack of moisture means a lack of protein to degenerate to the point where you get bacteria.”

But that doesn’t mean every finished product is immune. All it takes is the right conditions – such as damaged wrapping and humid weather. We’ve seen shrink-wrapped meaty bones (not produced by any of the companies listed here) laced with mold on the shelves of a local Trader Joe’s grocery store. Once moisture content rises inside the packaging, green fuzz can sprout.

“Also, where there’s enough moisture for mold to grow, you can have elevated bacteria levels,” adds Milligan. “You can have concerns about salmonella and E.coli.”

These issues are more likely to affect consumers and their food-handling practices, since healthy, adult dogs are usually unaffected by bugs that would lay humans low. Hand-washing is always recommended after touching a dog’s chew bones.

Well-dried bones in a dry environment can last a very long time on a shelf or in your pantry, which explains part of their appeal. Some owners trade weekly trips to the butcher shop for a box of dried bones. Others don’t have access to butcher shops, but can get dried or cooked bones from local pet stores.

Laura Herr of Jones Natural Chews said her company labels its products with sell-by dates, but it’s more to give the distributor, retailer, or consumer a benchmark than to warn against spoilage. “They have a very long shelf life,” she says. “We put our (sell-by dates) two years out. But we’ve had some bones in our testing area for eight years, and they still look beautiful.”

By reducing the moisture content of their products, most of these companies are able to forego the use of preservatives to keep the animal-based products from decomposing. An exception is Redbarn, which uses preservatives in its “stuffed” bones, which have artificially flavored and colored filling. The stuffing is either cheese-and-bacon, chicken, beef, or lamb flavored.

Super dry “sterilized” bones splinter into razor-sharp shards under pressure. Avoid them at all costs.

Jeff Baikie, co-president of Redbarn, defends the filling, which is mostly meat by-products with meat or poultry meal and lots of sugars, salt, and other flavor enhancers, on the basis that it’s meant as an occasional treat. “I’m not saying you’d want to feed this as a full diet, but two ounces once a week isn’t a big deal,” Baikie says.

Stuffing a bone creates added value for the consumer, Baikie told us, because a dog will remain interested in it much longer. And the processing of the bones Redbarn uses – stuffed or not – is minimal, he says; they are simply cleaned and dried.

At WDJ, we’re not wild about these filled bones. For one thing, with so many all-natural, unpreserved, and uncolored treats available today, we think owners can afford to be choosier about their dogs’ treats. Filling aside, we’re even more concerned about the bones themselves.

Dental dangers
There are two main knocks on dogs chewing bones: dental and gastrointestinal concerns.

Frank J.M. Verstraete, DVM, a diplomate of the American Veterinary Dental College and a professor of dentistry and oral surgery at the University of California, Davis School of Veterinary Medicine, agreed to evaluate a variety of cooked treat bones with regard to dental health. We brought him a bag full of commercial recreational chew bones to examine – roasted, smoked, dried, meat-on, hollow, stuffed, and so on. From his perspective, he says, none are safe for canine consumption.

“Basically, the main rule that we use is that you should be able to make an impression in the item with your thumbnail,” he says. “If you cannot, it’s too hard.” All the bones in our bag flunked his test.

Dr. Verstraete explains that hard, dried bones present an opportunity for dogs to crack premolars while gnawing. (There are four premolars on each side of the upper and lower jaws, directly behind the canine teeth.) Fresh, raw bones are preferable, but once they dry out they also pose a problem. In fact, on the day we interviewed him, he’d treated two dogs – both described by their owners as non-aggressive chewers – who had broken teeth on desiccated raw bones.

Nature’s Variety uses a slow-roasting process they say makes the cooked bone less brittle and hard. According to company president Bob Milligan, the final products have a moisture content of about 10 to 12 percent. “It probably is softer and contains more moisture at the time of manufacturing,” allowed Dr. Verstraete when he looked over some Nature’s Variety bones. “But once this has been on a shelf for a while, it’s too dry.”

Whether certain types of bones – say, ribs or bones from younger animals – tend to be safer is an open question. Dr. Verstraete says all evidence either way is purely anecdotal. But the extra-hard bones sometimes designated as appropriate for “aggressive chewers”? Steer clear. “Much too hard,” he says. “Good for a hyena, but not for a dog.”

While he is very critical of cooked and dried bones, Dr. Verstraete doesn’t go so far as to proscribe bones entirely, especially if a dog has been brought up on bones and uses them regularly for recreational chewing.

“As long as it’s a fresh bone, and an appropriate size and shape for the dog,” he says, letting your dog chew is fine. Dr. Verstraete recommends condyles (the lumpy knobs at the end of bones) over the tubular, middle portions of leg bones, because they are softer. Those leg bones are cortical bones, which have a high resistance to bending and torsion.

Cathy Dyer, DVM, a colleague of Dr. Verstraete’s at UC Davis, says the size of the bone is also very important. “For those people who really want to give their dog a bone – because let’s face it, it does really clean the teeth – I’ve always said give a great big bone, like a beef knuckle bone,” she says. The idea is to provide a bone that’s too large for a dog to get between his jaws and bear down, which could lead to tooth damage.

In addition to posing dental dangers, bones can also do something else: splinter. The reality is that virtually any bone, cooked or not, can splinter or break in the right circumstances. However, the manufacturers we spoke with said complaints about splintering were virtually nil.

Bob Milligan of Nature’s Variety says the secret to safer bones lies in the selection. “We try to select bones like the ham bone, which is the main femur bone of the pig,” he explains. “That is a medium hardness bone, either in the raw or roasted state. We found that the slow roasting helps soften that bone so splintering has not been a problem. We sell literally hundreds of thousands of those bones and have not had problems. I should add we always caution the pet caregiver to supervise the pet with bones, whether the bones are raw or slow-roasted.”

Jeff Baikie of Redbarn says his company has fielded “a few” complaints. “Any manufacturer who tells you different is probably lying,” he says. “But it’s very, very limited. What you’re worried about is splintering, and splinters getting lodged in the dog’s throat or intestines. But for the number of bones we sell, we might get three complaints a year, and we’re talking million and millions of bones.”

Then again, some said they were aware of problems with certain types of bones. “We have had requests from some customers to make a sterilized bone; they want it boiled, free of meat,” says Milligan, adding that Nature’s Variety does not make such a bone. “The problem we had, and why we did not pursue it, is the bones became very brittle, almost like glass. You could literally drop them and they would break or crack.”

Breaking bones
That was certainly our own experience in our informal test lab – the backyard of the editorial office of WDJ. Just for kicks, we decided to subject a wide range of commercial bones and some plain old “butcher bones” to some admittedly unscientific tests, to compare how the different products responded to various physical pressures. We included raw frozen bones, raw thawed bones, and a number of commercially prepared bones, including those with attached meat and tissues, sterilized bones, slow-roasted bones, joints, long bones, and even rib bones. Some of these commercial products were from the companies whose representatives we interviewed, while others were either not labeled or were competing brands.

Condyles break, but don’t shatter.

While we did not attempt to exactly simulate the forces applied by a dog’s teeth and jaws, we did subject each of them to a couple of light taps with a hammer, as well as a brief session of squeezing in a large iron vise. What we found was disheartening.

Every bone yielded to our tests – some even shattered like porcelain, leaving behind razor-sharp shards, and others resisted several whacks and/or turns of the vise before cracking. The raw bones were marginally softer, as was a ham bone from Nature’s Variety; these cracked and flaked apart. Still, they yielded small pieces. If ingested, what havoc could these splinters wreak on a dog’s mouth, throat, or stomach?

In the vise test, we wanted to approximate the pressure caused by a dog’s jaws closing down on a bone. Once again our test bones gave way – although the Nature’s Variety dry-roasted ham bone (which included condyles) did best, changing shape but not splitting or breaking.

When the bones cracked in the vise, they splintered. Some, like Smokehouse’s roasted rib bone, lost small, crumbly chunks; others, like Redbarn’s plain white bone, split up their length and fell apart. Even the moist raw bones split off sharp shards.

At the end of our experiment, sitting amid the rubble of broken bones and needle-sharp shards, we had some decisions to make.

We decided that it would be courting danger to recommend giving any cooked treat bones to a dog with large, strong jaws and an aggressive chewing style. Any of the offerings could be reduced to a pile of potentially harmful pieces or could cause a broken tooth.

For moderate chewers or small dogs, we could see giving them an extra-large bone – one that they couldn’t fit between their back teeth – and keeping a watchful eye on their activity.

Garth Merrick responded to our concerns by acknowledging that dangers do exist.

“There’s no question, if you break one it’s going to have some sharp edges,” he says. “If the customer will use common sense, I really think the amount of risk is minimized.”

Proper sizing, he says, is most crucial.

“If the people who buy the bones will size the bone to the size of the dog’s jaws and keep it big enough so they cannot fit it in and bear down with their back teeth, they cannot put enough pressure on it to break it,” he says. “Even though there is a risk, there are millions of satisfied people whose dogs have never had a problem.”

Laura Herr of Jones Natural Chews agreed that owner supervision and sizing were important, but also took it a step further, noting that certain types of bones are less prone to problems.

“There are several bones that do not splinter,” she says. “If you put a shank bone or a knee cap from the knee joint to your test, neither of these bones will splinter even for the most aggressive chewer. Any knuckle bone does not present danger of splinters. The bones that do splinter for the aggressive chewer are the straight bones, which we call center bones.”

Should you avoid bones entirely? There’s no easy answer, and it’s an individual decision. Some dogs will do fine on just about any sort of bone, while others will make mincemeat of even bones that are considered very safe.

After collecting chips, shards, and sharp fragments of bone from our testing grounds, we can’t help but think that sometimes it’s better not to give your dog that bone.


Also With This Article
Click here to view "What You Can Do."
Click here to view "If You Want Your Dog to Chew Bones..."
Click here to view "Results of WDJ’s Informal Testing."

-C.C. Holland is a freelance writer from Oakland, California.

Comments (0)

Be the first to comment on this post using the section below.

New to Whole Dog Journal? Register for Free!

Already Registered?
Log In