Comparison of long-term effects of ovariectomy versus ovariohysterectomy in bitches.

Although ovariectomy is less invasive and less time-consuming than ovariohysterectomy, most surgical textbooks recommend ovariohysterectomy for routine neutering of bitches. This advice is probably based on concerns about the development of uterine disease after ovariectomy. However, there is no evidence that conditions such as cystic endometrial hyperplasia (CEH)-endometritis develop in the ovariectomized bitch, unless progestagens are administered. The purpose of this study was therefore to compare the long-term effects of ovariectomy and ovariohysterectomy, including the incidence of urinary incontinence. Questionnaires were sent to 264 owners of bitches, in which ovariectomy (126) or ovariohysterectomy (138) had been performed as a routine neutering procedure 8-11 years earlier. Complete data were available for 69 bitches of the ovariectomy group and for 66 bitches from the ovariohysterectomy group. There were no indications that endometritis had developed in bitches of the ovariectomy group. None of the bitches was sexually attractive to male dogs after neutering. The occurrence of a clear to white vaginal discharge was reported in two bitches of each group, but none of these four bitches appeared to be ill during the periods when the discharge was present. Furthermore, with the exception of urinary incontinence, no problems were reported that could be related to the surgical neutering. Six of the ovariectomized bitches and nine of the ovariohysterectomized bitches eventually developed urinary incontinence. Of these 15 bitches (11%), 12 weighed more than 20 kg. Bouvier des Flandres bitches were at a higher risk of developing urinary incontinence than were those of the other breeds. The possibility that the urinary incontinence was due at least in part to other conditions must be considered, since eight of the bitches were 9 years or older before urinary incontinence occurred and seven of the incontinent bitches also had polyuria or polydipsia. There were no significant differences in the incidence of urogenital problems listed above between the bitches of the ovariectomy and ovariohysterectomy group. It is hypothesized that a uterine disease such as CEH-endometritis cannot develop after complete ovariectomy, unless progestagens are administered. The results of this study indicate that ovariectomy does not increase the risk of CEH-endometritis or other complications in comparison with ovariohysterectomy. It is concluded that there is no indication for removing the uterus during routine neutering in healthy bitches. On the contrary, ovariectomy should be considered the procedure of choice.