Since his purchase, Thor has had recurring drippy eyes. When his previous owners brought this concern up with the vet, they felt it was not taken seriously. So, during Thor's vaccination visit last week, I brought it up again. The vet's response was that the tear ducts could be flushed while Thor is anaesthetized for neutering. I informed her that I would be delaying neutering until Thor was around a year old. The vet objected to this, saying that 5 months was the optimal age. Having worked in an animal shelter for three years, I fully understand the problems of pet overpopulation and the importance of canine sterilization. I participated in the euthanasia of hundreds of unwanted animals. The shelter where I worked was a proponent of early-age spay/neuter and had a policy of neutering all animals prior to placement. This meant that puppies and kittens were often being sterilized at 8 weeks of age. I did not come lightly to my decision to hold off on neutering Thor.
Chris Zink is a veterinarian who is well-known and respected for her knowledge of the canine athlete. She has written extensively on canine structure and how it relates to athletic performance in dogs. I own two of her books which are extremely informative. In the packet that was provided by Thor's breeder was an article on the importance of waiting to neuter a weimaraner pup. As it turns out, it is all dogs who probably should be neutered after puberty. There are many deleterious effects of early (pre-pubescent) neutering of both males and females.
The first risk of early neutering is an alteration in the growth rate of certain bones. Apparently, growth plates are reliant on sex hormones to close at the appropriate time. Failure to close leads to abnormal growth which shows up as tall "leggy" dogs whose bones are not in the correct proportions to one another. As a result of this disproportion, dogs neutered prior to the development of adult sex hormones are more likely than those neutered later to develop hip displasia. In addition, one study showed that all neutered animals have a higher incidence of rupture of the anterior cruciate ligament. Both of these conditions may require surgery to repair.
Another study found that a variety of cancers occur at an increased rate in spayed and neutered canines. Those neutered prior to one year of aged had an increased risk of bone cancer. Since cancers are rampant on older dogs, I believe we must pay attention to these studies as one way to curb the incidence.
There are behavioral effects to early neutering as well. Those neutered early exhibited an increase (to my surprise) of sexual behaviors in both males and females. Noise phobias were increased in both genders while females developed more fearful behaviors in general, and males exhibited more aggression. I read long ago that dog aggression is most common between two spayed females.
As a result of my reading, and knowing that Thor will be well supervised and managed, I can only come to one conclusion. It is in the best interests of my dog to wait until one year (or thereabouts) prior to neutering.