The Sex Hormones
If you breed dogs like we do or keep a stud dog, hormone-controlled sexual behavior is of course desirable. Our bitches are in heat about every 9 months. During this time, we are particularly attentive, avoid overpopulated dog meadows and watch our bitches very closely. During the fertile days they are not allowed to go out into the garden alone, as a dog in love could climb our fence and ask for a date.
If you now hold a dog that is not intended for reproduction, you can quickly be tempted to put an end to the effects of the sex hormones. Be it to rule out annoying bleeding, to prevent the male in love from spitting out or even to end his possibly aggressive macho behavior, not to mention unwanted love affairs with consequences. But health can also play a role in the decision, if one assumes that the risk of breast cancer, prostate cancer etc. can be reduced by castration. A veterinarian often asks on the first visit when the neutering should be planned. I want to quote (again) Dr. Irene Sommerfeld-Stur from her book "Rassehundezucht - Genetik für Züchter und Halter (Genetics for breeders and keepers)". I do not give all the details, I can really recommend the book to the interested reader:
"A castration decision should always be considered very carefully, because the sex hormones are not only responsible for sexual behavior in the context of reproduction. They interact with other hormones and neurotransmitters and play a role in almost all metabolic areas. They are also able to penetrate into the cell nucleus and contribute to DNA switching. Sex hormones are therefore also epigenetically relevant. Incidentally, they share this property with the stress hormone cortisol. You should also know that the production of sex hormones is not limited to the respective gender. Male sex hormones are also produced in the female organism (...) and vice versa (...).
In addition to controlling sexual behavior, testosterone is stimulating and activating overall, and it can increase aggressiveness. The latter then very often leads to a male who is noticeable due to aggressiveness being neutered. However, castration can only reduce aggressiveness if this has actually been caused by an increased testosterone level. Since there are numerous other causes of aggressive behavior, castration will only be effective in part of the cases without a more detailed analysis of the reasons for the behavior.
What testosterone is for the male is estrogen for the bitch. It has an activity-enhancing, invigorating effect and, like testosterone, shows interactions with various neurotransmitters. There are also serotonin and dopamine players in estrogen, but also norepinephrine and glutamate, both of which include are responsible for learning and memory. Interaction with oxytocin appears to be particularly important, as it has a more pleasant and anxiety-reducing effect in the presence of estrogen (…)
One of the studies on the consequences of castration (overview at Sanborn, 2007) should be emphasized because of its impressive statement. This study was carried out on 189 female Rottweiler dogs (Waters et al., 2011). The average life expectancy in this breed is 9.4 years in the examined population. There was a group of bitches in this population that were remarkably older than the breed average. There were 83 bitches older than 13 years. A comparison was now made between the group of very old bitches and the group that had reached normal life expectancy. The fascinating result was that the longer the bitches were under the influence of estrogen, the greater their chance of being among the particularly old (...). There is hardly a more convincing argument against castration of a bitch.
When deciding to castrate a bitch, the possible psychological consequences should also be considered. The generally invigorating and activating influence of estrogen does not apply, bitches can therefore, depending on their other genetic makeup, become more phlegmatic, insecure and possibly even more aggressive (...)"
This is only an excerpt, further, as I said, can be read in the book. There, as in many other places, you can also find information on the health risks of castration. It has always been known that every operation is inherently risky. It is also not new that castrated dogs often suffer from urinary incontinence, obesity and hypothyroidism. Fur changes are only marginally mentioned here. On the other hand, it is often argued that castrated bitches cannot develop breast cancer and males cannot develop testicular and prostate tumors. That may be true, but the risk of other types of cancer in castrated dogs increases significantly. The article by the veterinarian Ralph Rückert is very interesting on the subject: "Castration in dogs - a paradigm shift" He reports on studies in which castrated dogs have a multiple risk of mast cell tumors, lymphosarcomas, bone cancer and other tumor diseases as well as impairments of the immune system were found. Here you can find more information about the influence of castration on the health of the dog - please read it!
There is more about castration, among others. on the side of the Zuchtstätte vom Steenbrook
Last but not least, I would like to point out the Animal Welfare Act. Among other things, it says here:
§ 6: It is forbidden to amputate parts of the body, in whole or in part, or to completely or partially remove or destroy organs or tissues from a vertebrate. (...)