We recommend all male cats be neutered.
For male dogs we offer this information and leave it up to the owner to decide if they wish to have this procedure done, with a few exceptions.
Exception 1: Both testicles must be present otherwise they should be neutered and not bred.
Exception 2: Other medical abnormalities of the gonads and associated structures.
We do prefer the males grow into their bodies prior to castration unless otherwise necessary due to disease.
There are studies* that show intact male dogs are less prone to orthopedic issues, obesity (unless severely overfed!), Lymphosarcoma and autoimmune disorders.
Hip dysplasia and cruciate ligament injury are common problems in neutered dogs. Neutered males were twice as likely to develop hip dysplasia. Intact males had a 7% incidence of cruciate ligament injury compared to 21% of neutered dogs. Neutered dogs were 3 times as likely to have Lymphosarcoma. The studies did point out that other cancers showed no significant difference.
Auto-Immune diseases studied included:
*Atopic dermatitis (ATOP, allergies), autoimmune hemolytic anemia (AIHA), canine myasthenia gravis (CMG), colitis (COL), hypoadrenocorticism (ADD), hypothyroidism (HYPO), immune-mediated polyarthritis (IMPA), immune-mediated thrombocytopenia (ITP), inflammatory bowel disease (IBD), lupus erythematosus (LUP), and pemphigus complex (PEMC).
Neutered dogs had a significantly greater risk of ATOP, AIHA, ADD, HYPO, ITP, and IBD than intact dogs with neutered females being at greater risk than neutered males for all but AIHA and ADD. Neutered females, but not males, had a significantly greater risk of LUP than intact females. Pyometra was a greater risk for intact females.
Behavior is multifactorial and so depending on the environment and training castrating may or may not have a significant effect. Although with male dogs less roaming, sexual behaviors, calming etc, were seen more so than females.
*PLoS One. 2013;8(2):e55937. doi: 10.1371/journal.pone.0055937. Epub 2013 Feb 13. Neutering dogs: effects on joint disorders and cancers in golden retrievers.
*Vet Med Sci. 2016 May 16;2(3):191-199. doi: 10.1002/vms3.34. eCollection 2016 Aug. Neutering of German Shepherd Dogs: associated joint disorders, cancers and urinary incontinence.
*BMC Vet Res. 2016 Dec 8;12(1):278. Gonadectomy effects on the risk of immune disorders in the dog: a retrospective study.
