Gonadectomy and behavior

Behavioral benefits of gonadectomy in dogs

© Dr Joël Dehasse

3 avenue du Cosmonaute, 1150 Brussels, Belgium


Speech given on Monday October 8 (in Gent) and Tuesday October 9 (in Namur), 2007.
Speech asked and sponsored by Royal Canin (Benelux).


  • Google: ‘behavioral effects of castration’: 640.000 ref.
  • If there were sound scientific evidence, the question would never arise.
    But castration is a question of culture and belief more than a question of science.
    In the USA, UK, Germany… many dogs are castrated but not in Latin countries.
  • It seems impossible not to be subjective in the question of being pro/contra gonadectomy. And the opinion change depending on the sex of the speaker. J
    After all, it’s a man who invented the anti-conception pill. Men have difficulties to suppress maleness but find easier to manage female sexuality.
    Is it surprising that everywhere in the world, bitches are spayed more often than dogs are castrated?
    Is it surprising that woman do object less than men to gonadectomy?
  • Except in a few cases (zoophily…), owners do not like to be pestered by their dog’s sexual behaviors.



  • Dog showing ‘epilepsy’ every 28 days…
  • Castrated Chihuahua marking with urine indoor
  • Castrated dog mounting other dogs, cats and people


Questions from http://www.gsdhelpline.com/castration.htm

  • My dog is aggressive towards the family. Will castrating him cure the problem?

  • My dog is aggressive towards visitors. Will … ?

  • My dog is nervous and aggressive towards strangers in the street. Will… ?

  • My two male dogs fight. Will…?

  • My dog is fine with other dogs when he is off the lead but aggressive towards them when he is on the lead. Will…?

  • My dog is aggressive towards other dogs when he is off the lead. Will…?

  • My dog frequently lift his leg and urinates in the home. Will…?

  • My dog constantly stops to urinate on trees, posts and walls. His bladder must be empty but he still manages to squeeze a drop out. Will…?

  • My dog is destructive when I leave him. Will…?

  • My dog constantly pesters and sometime mounts bitches. Will…?

  • My dog constantly escapes and stays away from home. Will…?

  • My dog mounts people’s legs. Will…?

  • My dog mounts the cushions when he is excited. Will…?

  • Should I allow my dog to mate to relieve his frustrations?

  • My husband is against castrating our dog. How do I convince him?

  • I want to train my dog to work and have been told that castration will make him lethargic. Is this true?


2 aspects to consider

  1. Well-being of dogs
  2. Well-being of people

Best solution is the well-being of dogs and people. Is it possible?


Scientific facts --------------------------------------------------------

What is sex?

  • Sex is an activity >  OCD
    Ag = Al + Av + Am + Ai + As
  • Sex is (often) an enjoyable self-rewarding activity
  • Sex has, behaviorally and cognitively, nothing to do with reproduction. It means that dogs do not thing about having offspring when they have sex.
    Sex drive is satiated by consuming ‘sex’, i.e.
    • communication (urine marking, pheromone),
    • competition (intermale/interfemale aggression),
    • courtship (flirting play)
    • copulation (mounting, including rape-like sexual aggression)
  • Sex in dogs is somato (hormone)-psychological and not psycho-somatic.
  • Sex is a very motivating behavior (sex drive / libido at the same level as survival and/or OCD).
    See Maslow pyramid of needs/motivations
  • Sex drive / libido # DA (+) reward centre in the mesolimbic system, responsible for desire and orgasm, Prolactine (-)
    Erection # Ach (+) and NO (Nitric Oxyd) (+), a lethal gaz very improbable as neurostransmitter, but nevertheless very active, decreasing Phosphodiesterase V (of which the blue pill (sildenafil / Viagra®) is an inhibitor.
    Ejaculation # 5HT2a (-) and NA (+)


Physiological effects of sex hormones

  • At birth, sex are already differentiated. During pregnancy, fetus are bathed in estrogens and progesterone (it does not seem to feminize males / if female fetus are exposed to testosterone, they become hermaphrodite), but before birth, testicles start producing testosterone ‘masculinizing’ (androgenization) all body parts, including brain. But even oestradiol is 8 times more potent in brain masculinizing in males[1]! Fetus produce alpha-foeto-protein, protecting against the effects of oestradiol (or else all fetus would be males)
  • Anabolic hormones
  • Increase of synthesis of proteins in muscles
  • Higher metabolic rates, and higher food intake (cohort study)
  • No direct control on food intake by sex hormones,
  • Blocking of growth of long bones (puberty)
  • Stimulation of erythropoietin > increase of red blood cells
  • Development of 2ary dimorphic sexual characteristics (neonatal period, puberty)
  • Development of sexually differentiated behaviors
  • Increase (x10) of preoptic centers in the brain (puberty)
  • Blocking of presynaptic DA and NA receptors in the brain, leading to increase sympathomimetic state
  • Estrogen is neurotrophic for the brain, activating genes responsible for synaptic creation, through NGF (nerve growth factor) and BDNF (brain-derived neurotrophic factor), preventing apoptosis and neuro- degeneration. Estrogen could be essential (in women) for the right function of the Ach related Meynert basal nucleus, fundamental for regulation of (verbal) memory (and involved in Alzheimer disease, prevented by administration of replacement estrogens).
  • Estrogen/progesterone # depression, with kindling effect (in women) (Stahl 562) [oral contraception in predisposed woman can induce/aggravate depression]
  • Testosterone is neurotoxic.
  • Estrogen is protecting bone mineralization


Intact male dimorphic behaviors

  • Increased urine marking, compared to female and castrated males
  • Roaming for sexual motivation
  • Mounting on dogs, people and other animals
  • Male-male aggression
  • Sexual motivation and readiness, increased when female in heat
  • Flehmen (salivation) with female sexual secretions and pheromones
  • Sexual emissions
  • Sexual frustration if excitement without copulation/masturbation
  • Testosterone levels # success in inter-male fights: winners have higher levels of testo than losers[2].
  • Testosterone increases the detection of maleness in urine (in mice)[3].
  • In men, aggression # testo (+) cortisol (-) levels in a simulated crisis game[4], men being more aggressive than women (but also losing their fights).
  • In people (male and female), testo (+) # more libido, sensation seeking, antisocial behavior, lower occupational status, extramarital sex, throwing things at spouses, using drugs or alcohol…[5]



Intact female dimorphic behaviors

  • Urine marking
  • Flirting, foreplay
  • Roaming
  • Mounting
  • Sexual readiness, acceptation of copulation (without aggression)


Physiological effects of Gonadectomy

  • Removal of risk of gonad cancer, cyst…
  • Reduction of risk of mammary cancer: before 1rst estrus 0,5%, after 1rst estrus 8%, then no more effect (nursing also reduces the risk)
  • Increase of risk of hypothyroidism (female)
  • Urinary incontinence: 9% (<20 kg) to 30% (> 20kg) to 65% (boxer breed), independently of age of Gonadectomy.
  • Increase of infectious diseases
  • Reduction of risk of prostate hyperplasia and increase of risk of adenocarcinoma
  • Increase risk of rupture of knee crossed ligaments
  • Increase of risk of aggravation of cognitive dysfunction (weird, since testrosterone is toxic for the brain in men)
  • Increase risk of developing diabetes mellitus in male and decrease risk in female
  • Increase risk of early death in boxers (cohort study)
  • Reduction of bone mass
  • Increased risk of hair matting or thinning
  • Increased risk of castrated dogs of being pestered, sniffed, and mounted by intact male dogs
  • No change in penile erection[6]
  • Reduced masturbation
  • Reduced ejaculation
  • Less reduction of copulatory behaviors in experienced males
  • Breed-specific increased aggressiveness of spayed females towards owners and strangers (Duffy, Serpell)   [slides[7]]
  • No effect on aggression in male dogs (Duffy, Serpell)


Effects of castration of male dogs on behavioral problems[8]

  • No effect
    • Fear of inanimate stimuli
    • Aggression towards unfamiliar people
    • Barking, hunting, affection, playfulness
  • Effect
    • Marking, roaming, mounting: >50% in 60% dogs, >95% in 25-40% dogs
    • aggression toward human family members, aggression toward other dogs in the household, aggression toward unfamiliar dogs, and aggression toward human territorial intruders: >50% in < 35% dogs
    • priapism (painful prolonged erection)




Observation facts ------------------------------------------------------


Conventional Gonadectomy

  • All male domestic animals (stallions, bull…) are castrated because they are then more docile. A castrated dog is easier to insert and manage in a family : it is more infantile, less/not preoccupied by sex and sexual competition, less irritable, less in a sympatomimetic state. A spayed bitch is less pestered by male dogs, hence not aggressed and less predisposed to develop dog (social) fear/phobia (Schroll).
  • Less problems of mood changes in a bitch and less difficulties in training (Schroll)
  • Satisfaction of clients
  • Easier work: Iditarod race: most dogs are castrated


Therapeutic Gonadectomy (and antihormone therapy)

  • V. Voith: if the behavior of one dog out of 100 is improved by castration, I will castrate them all
  • Sexual cycle related bipolar disorder in bitches, estrus or pseudocyesis phases
  • Food intake disorders: acute anorexia/hyporexia of male in presence of estrous bitches or chronic a/h in adolescent or adult male dogs.
  • Psychomotor fit in mal dogs related to estrus or menses of female owner(s)
  • Estrus-related inter-female aggression
  • Inter-male aggression
  • Sexual aggression


3 questions


  • Define: characterize a relationship
  • Privileges/prerogatives including overt sexual manifestations



Is gonadectomy a panacea in behavioral problems / disorders ?

  • Problems
    • Normal behaviors unwanted / unaccepted by owners
      • Sex related behaviors


  • Disorders
    • Age-related disorders : development or senescence
      • Hyperactivity
      • Senile dementia / cognitive dysfunction
    • Mood and emotional disorders :
      • Anxious d.: phobia, panic attack, generalized anxiety, specific anxieties: separation a., deritualization a.,
      • depressive d.: PTSD, (chronic) depression
      • hyper d.: unipolar hyper d., epidodic dyscontrol (rage d.)
    • Territory and social-related disorders
      • System adaptation d. (‘dominance’)
    • Repetitive behaviors disorders
      • (O) CD
    • Dissociative disorders
    • Organic-related disorders
    • Substance-related disorders
      • Hallucinosis
      • Cannabis induced d.
    • Personality disorders 
      • Dependent pd
      • Dyssocial pd
      • Dysthymic pd
      • Impulsive-explosive pd
    • Diverse disorders :
      • food intake d: effects of gonadectomy in testorenone-related hyporexia
      • sexual d: effects of gonadectomy in hypersexuality
      • sleep disorders


Surgery ----------------------------------------------------

When spay or neuter ?

Good question to get the best results and not induce behavioural problems.

  • Prevention: asap, i.e. before puberty, even as soon as 8 weeks of age. But be aware of anaesthetic problems and effects on brain development.
  • Prevention: before the people-dog bond is upset by the unwanted behaviors (sex, marking, aggression...)
  • Treatment:
    • Males: any age
    • Females: out of hormonal phases (anoestrus)
    • for inter-female aggression: both bitches at the same time


Testicles replacement

Diverse solutions do exist.

250.000 ‘neuticles®’ placed…


Neutering/spaying, does it matter?

Owners get dogs for their own pleasure, their own needs.

Most dogs’ behavioral needs are not fulfilled. Most dogs do not get enough activity, they do not have a function, an aim, except to wait for their owners to come back, do nothing when alone, do the things the owners like them to do, walk at the owner’s pace and not too fast (i.e. at a dog’s pace), stay infantile, playing the replacement baby/child, accepting to be petted all day long (without saying ‘no’ of course), etc. Most dogs are passively ‘mistreated’, their behavioral needs not satisfied.

Except a few helping / dancing / working / trained / circus… dogs, they have no ‘dignity’ any more, no freedom, no right to take any decision. They are ‘on the leash’, figuratively speaking.

Hence, does it matter if we also neuter them?


Holistic vision

  • Any vision is subjective
    Sexuality is linked to creativity. It is a metaphor of creativity. Suppressing – not managing – creativity has a very deep effect in people.


Gonadectomy is far from a universal remedy for behavioral problems.

But it looks like it may increase behavioral and social comfort both in owners and animals.



http://www.geocities.com/poilsplumesecailles/hormones_sexuelles.html: 58 ref.


http://acc-d.org/2006%20Symposium%20Docs/Duffy2.pdf: Duffy, Serpell. Non-reproductive effects of spaying and neutering on behavior in dogs.

Elective Gonadectomy in Dogs: A Review" by Katharine R. Salmeri, DVM, Patricia N. Olsen, DVM, Ph.D. and Mark S. Bloomberg, DVM, MS. It was published in the April 1, 1991 issue of the Journal of the American Veterinary Medicine Association, volume 198, pages 1183-1191.





[1] Caston J. psychophysiologie. P. 261.

[2] Toates F. Control of behaviour. Springer/open U., 1998. p. 101.

[3] Toates, p. 105.

[4] http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1004&context=politicalsciencehendricks

[5] http://findarticles.com/p/articles/mi_m2372/is_n4_v34/ai_20536044/pg_4

[6] Dr. Kate E. Creed, Effect of castration on penile erection in the dog, School of Veterinary Studies, Murdoch University, Western Australia, and Reproductive Medicine Research Institute, Queen Elizabeth II Medical Centre, University of Western Australia, Western Australia, Australia

[7] http://acc-d.org/2006%20Symposium%20Docs/Duffy2.pdf: Duffy, Serpell. Non-reproductive effects of spaying and neutering on behavior in dogs.

[8] Neilson, J.C., R.A. Eckstein, and B.L. Hart (1997). Effects of castration on problem behaviors in male dogs with reference to age and duration of behavior. Journal of the American Veterinary Medical Association 211(2): 180-182.


© Dr Joël Dehasse - Behaviorist veterinarian - 2007-10-14