Castration is one of the most common procedures for controlling reproduction in dogs. It is also used to prevent testicular cancer and prostatic hypertrophy in males, as well as to eliminate oestrus and decrease the risk of mammary and ovarian tumours in females.
It is more common in female dogs, although it is increasingly used in males, reducing behavioural problems such as aggressiveness, as demonstrated in this study published in the Journal of the American Veterinary Medical Association 1.
Sterilisation is intended to inhibit the functioning of the testes and ovaries , and this can be achieved by surgical removal or through chemical procedures that act by causing fibrosis, as in the case of sclerosing agents or by blocking the production of eggs and sperm . Both alternatives are usually quite safe, but their results and patient outcomes differ.
Results and evolution of surgical and chemical castration
Post-castration of male dogs , some complications secondary to the procedure may occur. Pain and inflammation are the most common complications of surgical castration, especially when using the pre-scrotal technique, which is characterised by greater inflammation and slower recovery in comparison with the scrotal technique2. Sometimes bacteriuria develops, although its prevalence does not exceed 2.1%.
In comparison, chemical castration usually has fewer postoperative complications than surgical castration. A study published in the Veterinary Journal 3 comparing postoperative results in 54 adult male dogs undergoing chemical castration with zinc gluconate and 55 other male dogs undergoing surgical castration detected the presence of inflammation and/or ulceration i n both procedures, but especially in surgical castration.
These researchers evaluated the onset of postoperative complications such as inflammation, ulceration in the case of chemical castration, and dehiscence in surgical castration at 3, 7, and 14 days after castrating the dogs . They found that 22 of the dogs castrated by surgery and 7 of the animals chemically castrated experienced inflammation and/or ulceration while only 2 of the dogs subjected to chemical castration and 1 of the dogs castrated by surgery needed surgical repair after the procedure.
Subsequent research4, confirmed these results. The researchers analysed side effects in 38 adult male dogs castrated with a zinc gluconate injection . They found that post-castration of the dogs, only 2.6 % of the animals had inflammation in the scrotal region , a figure somewhat lower than the 6% incidence reported in veterinary literature.
As far as hormone levels are concerned, a study by Dr. Vanderstichel's team 5In 118 male dogs, 36 of which were chemically castrated and 39 surgically castrated, analysed testosterone levels before, at the time of treatment and post-castration of the male dogs.
After treatment, all surgically castrated dogs had testosterone concentrations below 1.0 ng/ml, while 66% of chemically castrated dogs showed no changes in testosterone levels at 4 and 6 months after treatment . In fact, after 6 months only 30% of chemically castrated dogs had a low testosterone concentration (< 1.0 ng/ml), similar to that of male dogs undergoing surgical castration.
In terms of effects on behaviour, no major differences have been reported in either type of procedure. However, a study presented at the 15th Congress of the European Veterinary Society for Small Animal Reproduction 6, which compared the effect of surgical and chemical castration on canine behaviour, found that female dogs undergoing surgical castration experience greater inhibition in their sexual behaviour than their chemically castrated peers .
