Effect of Early-Age Gonadectomy on Feline Behavior

Prepubertal gonadectomy, or early-age/pediatric neutering, is a common procedure that permits animals to be neutered before adoption and before the onset of puberty. However, the practice remains controversial due to practitioner concerns about procedural safety and potential negative effects on animal health and behavior.

Although a number of studies have been published evaluating the long-term outcome of gonadectomy performed at both early and traditional ages, the effects of prepubertal gonadectomy on behavior are not well understood.

In a recent long-term prospective study, behavioral data were collected and compared from cats gonadectomized prepubertally (8-12 weeks of age) and at traditional age (6-8 months).

Study Design

The purpose of this research was to extend data collection originally undertaken within the framework of a study known as the Sterycat project.

Kittens with an estimated age of 8 to 12 weeks were enlisted from Flemish shelters between May 2010 and August 2012. The selected kittens were assigned randomly to 1 of 2 groups and underwent gonadectomy at the age corresponding to their assigned group. Two-thirds were assigned to the prepubertal gonadectomy (PPG) group and neutered at 8 to 12 weeks. One-third were assigned to the traditional-age gonadectomy (TAG) group and neutered at 6 to 8 months of age.

Behavioral data were collected from adopters of these kittens via an online survey. During the Sterycat project, the adopters were asked to complete an online survey at 5 post-adoption time points (2, 6, 12, 18, and 24 months). Data collection for this part of the study ended in mid-2013. To extend the follow-up period, another online questionnaire was created in 2016 using a subset of questions from the original survey. Time after adoption for this survey ranged from 60 to 84 months.

Respondents were asked about the occurrence of the same behaviors in each survey, whether a certain behavior was currently being expressed by their cat and, if not, whether it had been expressed in the previous 2 years. Respondents who answered affirmatively to either of these questions could indicate whether the behavior was considered by them and/or other family members to be disturbing.

The data obtained from the follow-up survey were first examined using descriptive statistics. Next, inferential statistical analyses were performed on the combined dataset. Specifically, the effects of treatment group and sex on the total number of potentially undesirable behaviors and on the occurrence of individual potentially undesirable behaviors were evaluated.

Results

Data were collected for 162 cats (110 PPG, 52 TAG) during the follow-up survey. The male:female ratios were 61:49 and 25:27 for PPG and TAG cats, respectively.

For both groups, the average total number of potentially undesirable behaviors per cat was 3.9 ± 2.3 (range, 0-12). For undesirable behaviors, it was 0.9 ± 1.6 (range, 0-9).

The analysis revealed no significant effects of any of the examined main effects (group, sex,

time point) or the interactions thereof on the total number of potentially undesirable behaviors per cat. The same was true for the total number of undesirable behaviors per cat. No significant effects of group, sex, or the interaction thereof were found for the 10 potentially undesired behaviors, which included hunting, fearful behavior, destructive behavior, attention seeking, stealing of food, excessive vocalization, non—play-related aggression toward animals, house soiling, sexual behavior, and non–play-related aggression toward humans.

Clinical Significance

The authors found no indication that gonadectomy at an early age causes the occurrence of potentially undesirable behavior at a different level than for cats undergoing TAG.

Dr. Spindel serves as the shelter medicine consultant and student advocate for VIN. She initiated and completed the first residency in shelter medicine with a master’s of clinical sciences through Colorado State University in 2007, and then worked as the senior director of shelter medicine at the ASPCA for 10 years. She is a member of the Shelter Medicine Organizing Committee and Residency Committee for Shelter Medicine for ABVP. Dr. Spindel lives on a small acreage in Colorado with her daughter and dogs, cats, chickens, horses, and donkeys.