For today’s edition of Dear Mark , I’m answering three questions from last week’s Weekly Link Love comment section . They’re all about dogs. First, are there negative health effects to neutering or spaying? Second, do grain-free dog diets give dogs dilated cardiomyopathy, a kind of heart disease? What’s the alternative? And third, what is in my opinion the ideal dog diet—and should everyone be feeding it to their dogs?
Mark, wouldn’t neutering dogs cause some long term negative health effects in them, as I assume it would in humans?
As you might expect, removing a dog’s testicles or ovaries—major reproductive and endocrine organs—can have negative effects. That’s just common sense, and we have observational studies paired with physiological mechanisms to make the case. The best-studied complications are cancer and joint disorders.
Among German shepherds , 7% of intact males were diagnosed with a joint disorder. 21% of males who’d been neutered before age 1 had a joint disorder. 5% of intact females were diagnosed; 16% of spayed females were diagnosed.
Among a group of 700+ golden retrievers , 5% of intact males had hip dysplasia, while 10% of early neutered males had it. No intact dogs had ever had any cranial cruciate ligament (an important ligament in the dog knee) tears, while 5% of early neutered males and 8% of early spayed females had torn one. 10% of early neutered males had a diagnosis of lymphoma, three times the rate of intact males. In females, late spaying (after 1 year of age) seems to have increased the rate of certain cancers, including hemangiosarcoma (a blood vessel cancer) and mast cell (breast) tumors.
Similar results with regards to joint disorders have also been found  in labrador retrievers.
Both spaying females and neutering males appears to increase the risk of heart cancer , a fairly common cancer in dogs. Spayed females have the greatest risk of all.
Early spayed or neutered Rottweilers have an increased risk of bone cancer , another common disease to the breed.
Neutered/spayed dogs have a higher risk of hypothyroidism .
Intact dogs have higher metabolisms and lower appetites. The opposite is true for neutered dogs , which could explain the rise in pet obesity.
If you’re going to neuter a dog, I’d recommend waiting as long as you can. At the least 1 year, and ideally longer until sexual development completes. That allows the dog’s joints, muscles, and skeletal tissue to reach its full potential.
Also realize that the sex hormones aren’t only about sex or physical/structural development. They also help determine mental and psychological development.
Interesting SwS post about dogs. I would caution people to make assumptions canines need the same diet as people. Recently, many folks are discovering that dogs on a grain free diet seem to have a higher likelihood of developing hart issues. My house is kind of an n=14 experiment and I would guess that our dogs get on the active side in terms of exercise. We also have three dozen sheep, two dozen ducks, and a bunch of chickens. My wife is a dog trainer so in addition to our dogs she works with a bunch more. Too much info to post here but look up diet-associated dilated cardiomyopathy and some of the recent studies. The research is not yet to the stage where they know what causes DCM but it appears that dogs that are on “boutique exotic grain free (BEG) diets seem to be much more likely to develop DCM.
The way this research is presented in the media, most people assume that the problem with grain-free diets are that they’re too high in meat. That dogs need “heart healthy whole grains,” just like people supposedly do.
The reason “grain-free” dog diets are linked to dilated cardiomyopathy is not that these animals are eating too much beef, lamb, chicken, and fish protein. It’s that they’re replacing the grains with potatoes and peas, lentils, and other legumes and inducing taurine deficiency. Taurine deficiency-induced cardiomyopathy is well-established in cats, who cannot synthesize taurine on their own and must consume it directly in the diet. Dogs can synthesize taurine themselves, but they’re also adapted to a diet rich in taurine-rich meat, so it’s smart and evolutionarily congruent for them to also eat high-taurine diets—which must contain meat.
Say what you will about grains. I’m no fan of them for dogs (or humans , for that matter), but they do possess the amino acid precursors for taurine synthesis.
A response from a veterinary nutrition researcher at Tufts University claims that taurine probably isn’t the cause, instead suggesting that the “exotic meats” found in grain-free diets are likely candidates. She goes on to warn against raw-fed diets as well, since they “increase your dog’s risk of many other health problems.” She fails to specify which health problems raw meat and bone diets increase, but since she has some acronyms after her name we can trust her.
It’s odd, because I’m aware of some actual benefits to feeding dogs raw meat and bone diets:
Improved immune gene expression , indicating lower inflammatory status compared to kibble-fed dogs.
Improved gut biome  compared to kibble-fed dogs.
Purina funded the Tufts University veterinary nutritional center where the writer of the article resides, which may or may not have affected her opinions.
In your opinion what should we feed our dogs?
Ideally, we should feed our dogs a well-formulated, nutrient-dense diet based on raw animal foods: muscle meat, bones, organs, seafood, eggs, quality dairy, and select supplemental foods. In other words, the ideal dog diet would look a lot like a really good carnivorous human diet.
The problem is that you have to do it right. It’s easy to do it wrong. One thing the dog food companies are pretty good at is avoiding gross deficiencies. The calcium:phosophorus ratio will be right. Most of the nutrients may be synthetic additions to refined junk food, but the basics will be there. This doesn’t always hold (see the dilated cardiomyopathy scandal mentioned above), of course, and it tends to cause chronic diseases like obesity and diabetes from mismatched macronutrients, but at least a kibble fed dog probably won’t develop osteoporosis.
Certain fish are dangerous when fed raw without adequate preparation . Pacific-caught salmon off the coast of California, Oregon, and Washington can carry parasites that kill dogs (and other canids like wolves and coyotes). Freezing long enough at a low-enough temperature will kill the parasite, but you really have to be careful.
Dogs need to eat bones for the calcium and to keep their teeth clean, but they can break teeth on the wrong kind of bone. Load-bearing ruminant bones are good for gnawing, but not for eating. Do you know the difference?
Dogs need connective tissue , just like people. People can just throw some collagen powder  in their coffee . Dogs really can’t. Are you going to seek out chicken feet, pork skin, beef tendons, green tripe for your raw-fed dog?
Dogs who spend all their lives on kibble only to be given a plate of turkey necks, beef liver, and lamb trim might not know what to do with themselves. Just like people who’ve spent their lives in restrictive high-heeled shoes can get into trouble when they try running a marathon in bare feet , dogs who are used to hoovering up kibble can get into trouble when they try to eat a neck for the first time.
None of this stuff is a deal-breaker. It can be done. Ideally, it should be done. But it does take time and energy to do things right. It’s harder—and better, don’t get me wrong—than just dumping some kibble in a bowl.
Take care, everyone. Thanks for reading and if you have any follow up questions, let them loose down below.