Jc. Neilson et al., 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), 1997, pp. 180
Objective-To determine whether 9 problem behaviors in adult male dogs
were affected by castration and to examine the influence of age and du
ration of problem behavior on behavioral effects of castration. Design
-Cohort study. Animals-57 male dogs > 2 years old at the time of castr
ation that had greater than or equal to 1 of the targeted problem beha
viors. Procedure-Data were collected by telephone contact with owners
to identify dogs that had greater than or equal to 1 problem behavior
before castration and to estimate the improvement (ie, decrease) in th
e objectionable behaviors after castration. Problem behaviors of inter
est included urine marking in the house, mounting, roaming, fear of in
animate stimuli, aggression toward human family members, aggression to
ward unfamiliar people, aggression toward other dogs in the household,
aggression toward unfamiliar dogs, and aggression toward human territ
orial intruders. Results-Effects of castration on fear of inanimate st
imuli or aggression toward unfamiliar people were not significant. For
urine marking, mounting, and roaming, castration resulted in an impro
vement of greater than or equal to 50% in greater than or equal to 60%
of dogs and an improvement of greater than or equal to 90% in 25 to 4
0% of dogs, For remaining behaviors, castration resulted in an improve
ment of greater than or equal to 50% in < 35% of dogs. Significant cor
relations were not, found between the percentage of improvement and ag
e of the dog or duration of the problem behavior at the lime of castra
tion. Clinical Implications-Castration was most effective in altering
objectionable urine marking, mounting, and roaming. With various types
of aggressive behavior, including aggression toward human family memb
ers, castration may be effective in decreasing aggression in some dogs
, but fewer than a third can be expected to have marked improvement. A
ge of the dog or duration of the problem behavior does not have value
in predicting whether castration will have a beneficial effect.