What is the effect of sex hormones on dog development?

Our question this week was:

This is really not a question but a comment. Don't you think it's about time someone mentioned the important roll the sex hormones play in growth and development in dogs? Bone and muscle growth are the two things that I would like to hear discussed. Although a lot of research has not been done in the important role of the sex hormones play from birth to old age in a dog, it's in any physiology book on canines and anyone with a knowledge base to understand it will understand it. A lot has been said about neuter and spay. It seems to me that the people that promote neuter and spay should be responsible and accountable informing about the short and long term effects both good and bad about neuter and spay especially early neuter and spay. Many medium and large breed dogs do not complete their growth and development by one year. Could not having a fully functional endocrine system alter the growth and development? I have been told many times there is no research to support complications of neuter and spay. Like I said walk through the roll of the endocrine system of canines and if you have the background in the physiology you can not only understand it but should be able to put the role in lay terms for the general public to understand it. Welcome you comments concerning this matter.




Hi – thanks for your interesting email. You bring up some very interesting points about the requirements and function of sex hormones on the growth and development of the dog's body.

I think early spaying and neutering can alter the muscling and development of dogs. However, I have not read anything (because I think it is a poorly researched area) that this causes a shortened life span or long term health problem in dogs.

Since you brought up such and interesting question and point, I asked some of my colleagues about their thoughts. They basically said the same thing – they thought that there was certainly a role that sex hormones play in normal growth and development but the problems associated with early spay/neuter have not been well documented, especially relative to the endocrine system.

To be honest, I think that huge number of unwanted and euthanized shelter pets every year has altered the recommendations on spay/neuter. I think if there was not such a HUGE pet overpopulation problem, that the recommendation for spay/neuter would be less aggressive and more emphasis on what is best for the dog (as far as when they should be spayed or neutered) would be more important.

One problem many humane societies have had is they allow a pet to leave unspayed or un-neutered making it the responsibility of the owner to do at a later date which they don't do. Then what happens is that they dog grows up to wander the neighborhood breeding more dogs. This results in more unwanted pets to come in to their facility for possible euthanasia. So very young spay neuter programs have come in to place to prevent those issues.

Best of luck!

Dr. Debra

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