Zoals ik in een ander topic al vermeldde, ben ik geabonneerd op the peeing post van mogens eliasen en in dat mailtje stond het volgende verhaal over castratie (vraag me af of dit ook geldt voor katten maar groot kans van wel). Stuk is wel in het Engels, als ik tijd heb en jullie dat willen, kan ik het wel vertalen hoor!
More spay/neuter stuff...
Leslie made me aware of another aspect of the spay-neuter dilemma that I wasn't aware of - but it makes sense when you consider that growth is partially controlled by sexual hormones. It is actually the sexual hormones that get produced at puberty which are the main responsible reason for the bones to stop growing! Now, when we eliminate puberty by spaying/neutering early, this will cause havoc in the bone growth control...
Although the article Leslie referred to is a bit tough to read, I still find it worth bringing to you as it is. It is written by Chris Zink, a veterinarian with a specialty in canine sports (more info at http://www.caninesports.com). Even if you do not consider your dog an athlete or potential athlete, the general health aspects are still there...
Early Spay-Neuter Considerations for the Canine Athlete
There are a number of studies that suggest that those of us with canine athletes should be carefully considering our current recommendations to spay or neuter all dogs at 6 months of age or earlier. A study by Salmeri et al in 1991 (Salmeri et al JAVMA 1991;198:1193-1203) found that bitches spayed at 7 weeks were significantly taller than those spayed at 7 months, who were significantly taller than those not spayed (or presumably spayed after the growth plates had closed). The sex hormones close the growth plates, so the bones of dogs or bitches neutered or spayed before puberty continue to grow. This growth frequently results in a dog that does not have the same body proportions as he/she was genetically meant to. For example, if the femur is normal length at 8 months when a dog gets spayed or neutered, but the tibia, which normally stops growing at 12 to 14 months of age continues to grow, then an abnormal angle may develop at the stifle. In addition, with the extra growth, the lower leg below the stifle becomes heavier (because it is longer), causing increased stresses on the cranial cruciate ligament. This is confirmed by a recent study showing that spayed and neutered dogs have a higher incidence of CCL rupture (Slauterbeck JR, Pankratz K, Xu KT, Bozeman SC, Hardy DM. Canine ovariohysterectomy and orchiectomy increases the prevalence of ACL injury. Clin Orthop Relat Res. 2004 Dec;(429):301-5).
In addition, a study in 2004 in JAVMA (Spain et al. JAVMA 2004;224:380-387) showed that dogs spayed or neutered before 5 1/2 months had a significantly higher incidence of hip dysplasia than dogs spayed or neutered after 5 1/2 months of age. If I were a breeder, I would be very concerned about this, because it would mean that I might be making incorrect breeding decisions if I were considering the hip status of pups I sold that were spayed or neutered early. Interestingly, this same author also identified an increased incidence of sexual behaviors in males and females that were neutered early.
A number of studies, including the one by Spain referenced above, have shown that there is an increase in the incidence of female urinary incontinence in dogs spayed early. This problem is an inconvenience, and not usually life-threatening, but nonetheless one that requires the dog to be medicated for life.
Yes, there is the concern that there is an increased risk of mammary cancer if a dog has a heat cycle. But it is my observation that fewer canine athletes develop mammary cancer as compared to the number that damage their cranial cruciate ligaments. In addition, only about 50 % of mammary cancers are malignant, and those that are malignant don't metastasize very often, particularly in these days when there is early identification and removal of lumps found on our dogs.
In addition, when considering cancer, there is another study of 3218 dogs that showed that dogs that were neutered before a year of age had a significantly increased chance of developing bone cancer (Cooley DM, Beranek BC, Schlittler DL, Glickman NW, Glickman LT, Waters D, Cancer Epidemiol Biomarkers Prev. 2002 Nov;11(11):1434-40), a cancer that is much more life-threatening than mammary cancer, and which affects both genders.
Finally, in another study, unneutered males were significantly less likely than neutered males to suffer cognitive impairment when they were older (Hart BL. J Am Vet Med Assoc. 2001 Jul 1;219(1):51-6). Females were not evaluated in that study.
For these reasons, I have significant concerns with spaying or neutering dogs before puberty, particularly for the canine athlete. And frankly, if something is more healthy for the canine athlete, would we not also want that for pet dogs as well? I think it is important, therefore, that we assess each situation individually. If a pet dog is going to live with an intelligent, well-informed family that understands the problem of pet overpopulation and can be trusted to keep their dogs under their control at all times and to not breed them, I do not recommend spaying or neutering before 14 months of age.
Chris Zink
Well, Chris' final words do not take the full consequence of the evidence and logic provided. There is no reason whatsoever to put a limit at 14 months when we consider that there are other internal processes than growth of bones that depend on a proper balance of the sexual hormones. It appears, once again, that there is only one good way out of this spay/neuter problem: responsible dog ownership... and that does not include castrating your pet.
The more I think about it, the more I am inclined to say that if dealing with the sexual issues for a pet dog is too much, then owning a pet dog is too much... I just don't like all this "tampering with Nature" for no other purpose than human convenience. But I can also see that, until the average dog owner in North America accepts the responsibility of at least educating him/herself about the fundamentals of responsible dog ownership, then the consequences of leaving all dogs sexually intact would lead to an explosion of irresponsible breeding on this continent....
