Desexing dogs as a means of decreasing the generally regarded sexually dimorphic behaviors of urine marking, mounting, and roaming

Desexing (castrating, ovariectomizing/neutering) and a dog's sex are topics of relevance to many dog owners. We studied the relationship between desexing and three behaviors that are presumed sexually dimorphic, that is, differ in occurrence between the sexes. Urine marking, mounting, and roaming were used as models for studying the effects of desexing on (unwanted) behavior in dogs. We assessed the relationships between the occurrences of the three behaviors and the four factors of the dogs’ sex, sexual status, desexing age, and age in general. A convenience sample of dog owner reports was collected with an online survey and 982 records were analyzed with Chi-square tests. Counts were expressed in cross- tables of the behavior being present or absent and one of the aforementioned four factors. Urine marking occurred most frequently in intact male dogs (78%, N = 188), with significant differences compared with intact females (41%, N = 48; P < 0.001) and desexed males (66%, N = 202; P = 0.002). There was a trend for mounting occurring more frequently in intact males (25%, N = 60) compared with intact females (17%, N = 19; P = 0.085), and a significant difference between intact and desexed males (25%, N = 60 vs. 18%, N = 54; P = 0.043). Roaming occurred similarly in males and females, and in intact and desexed male dogs. For none of the three behaviors, there were differences between intact and desexed female dogs. In intact male dogs, age-related differences were found for the occurrence of mounting (39%, N = 29 of the dogs<2 years vs. 13%, N = 4 of the dogs>8 years) and roaming (46%, N = 34 of the dogs<2 years vs. 20%, N = 6 of the dogs>8 years). Such differences were not found for females or for urine marking in males. Mounting and roaming occurring less often in older male dogs suggest that these behaviors may decrease with age, naturally or through other factors. Our cross-sectional study shares with many earlier studies that its setup does not establish causal effects of desexing and we recommend large-scale prospective studies as a next step in providing scientific evidence for how behavior is affected by desexing. More knowledge of the influence of sex hormones on behavior in dogs is needed to support decisions on desexing individual dogs for reasons of unwanted behavior, which will benefit both the dogs and their owners.