Giants and Bone Cancer

Giants and Bone Cancer

This post is to offer some information has concerning giant breeds and a particularly lethal type of cancer; osteosarcoma, or bone cancer. This was brought to my attention by a reader, and I’m very grateful for the heads up. There is a terrifying 80% fatality rate with this type of cancer.

xrayIt presents most typically as lameness in middle aged or elder giant breed dogs, though it can appear first in the jawbones or other places. Being a highly aggressive form of cancer, over 90% of dogs diagnosed already have had the cancer spread when it is discovered. Often, a biopsy is required to rule out other diseases and be certain that the changes seen on x-ray are indeed osteosarcoma.

The causes aren’t nailed down by science, but there are known risk factors, from genetics to diet. Osteosarcoma tends to run in families, so careful selection of the breeder’s bloodlines when you buy your puppy is very important.

Close relatives, such as a sire or dam, siblings, grandparents, aunts and uncles, that have developed cancer increases the risk of your pup developing it too. This has been linked to a specific gene:

There is research suggesting flouride in the drinking water is also a potential cause of osteosarcoma, in dogs and humans. Another risk factor is a popular insect growth regulator used orally for flea control in dogs and cats, diflubenzuron.  There is an increased incidence of both hemangiosarcoma and osteosarcoma in animal studies.

One of the biggest suspected factors in the later development of bone cancer is the speed of growth as an immature puppy, as most bone cancers originate near growth plates in long bones. This makes a diet of controlled calories, minerals, and protien (see feeding and growth page, or foods I recommend pages) even more vital than simply avoiding HOD or PANO in a puppy. The puppy’s diet has life long impact.

The growth rate risks also makes pediatric spaying and neutering of giant breeds an even worse idea than free feeding any old food. Many vets who should well know better, recommend desexing from 6-9 months old, some as young as 6-8 weeks old. Humane organizations as well push heavily for desexing, to reduce overpopulation. The problem isn’t the dogs, it’s the irresponsible owners.

A more detailed explaination of pros and cons of desexing:

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I hope you will resist the pressure to spay and neuter before maturity, and be prepared to argue a bit with most breeders and rescues, who are understandably concerned that a buyer will turn around and breed their puppy without permission.

But the risks of early spaying and neutering are substantial, and not just for bone cancer. It has long been known that desexing before maturity, especially before 1 year old, drastically increases the growth of giant breeds. The growth plates of desexed giant breed puppies do not close and cease growing at the appropriate time.

Personally I think this dog above, the world record holder of the tallest dog, has other metabolic issues as well that haven’t become known. But it is definitely known that pediatric spaying and neutering lengthens the bones, because the growth plates do not close at the right time. This essentially creates a tall, skinny, thin boned dog that just grows and grows and never fills out as they should.


Here is a picture of an intact dog, whose sex hormones allowed them to grow normally, a dog owned by an excellent breeder, JP Yousha. You can see the obvious differences, from a good muscle content, to a straight back, and well proportioned legs.

The additional growth time caused by desexing before maturity has shown to increase the risk of bone cancer dramatically, from 50% to 65% or more depending on the breed. It is particularly high in giant breeds (100+ pounds).

For more information:


Posted by greatdaneservicedog on December 29, 2012

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