Most of the testosterone is formed in the testes, so having your dog neutered will greatly decrease circulating levels of testosterone. Unfortunately, not all aggressive behavior is due to testosterone, but neutering often helps decrease the incidence. Older, uncastrated male dogs often develop an enlarged prostate. As the prostate enlarges, it often puts pressure on the colon and rectum, causing straining and difficulty during defecation. An enlarged prostate also predisposes dogs to develop prostatic infections.
Prostatitis leads to bloody urine and difficult or painful urination.
Neutering your dog at a young age will prevent prostatic enlargement. The good news is that even if your dog has already developed an enlarged prostate, neutering will cause the prostate to shrink. Neutering a male cat prior to the start of spraying behavior should keep them from developing the habit of spraying, neutering will not always make them stop. Unfortunately there are other causes of feline urine spraying, but this is the easiest one to prevent. We recommend that all mixed breed pets be spayed.