A Prospective Cohort Study Investigating the Behavioural Development of Bitches in a Guide Dog Training Programme Neutered Prepubertally or Post-Pubertally

Abstract

There are few studies that investigate the effect of neutering bitches before or after puberty. The majority of current literature examining the impact of the timing of neutering on health and behaviour has used age rather than the onset of puberty as the key variable. The aim of this prospective cohort study was to investigate the effects of timing of neutering in relation to puberty on behaviour in female dogs reared and trained in an assistance dog programme. The study examined data for bitches neutered before or after puberty to compare scores for six behavioural factors (training and obedience, aggression, fear and anxiety, excitability, attachment and attention-seeking, and social behaviour) measured at 1 and 3 years of age. Labrador and Golden Retriever crossbreed bitches were neutered before (n = 155) or after (n = 151) puberty. Neutering before or after puberty had no impact on mean scores for the six behavioural factors at 1 or 3 years of age. When examining the change in behavioural factor scores between 1 and 3 years of age, only aggression behavioural factor scores were influenced by neutering before or after puberty. Bitches neutered after puberty were less likely to have aggression factor scores that increased between 1 and 3 years of age (OR = 0.959, 90% CI = 0.924 to 0.995, p = 0.06). However, the majority of bitches scored “0” for aggression at both time points (indicating no aggression behaviours were observed), and the number of bitches for which scores increased between 1 and 3 years of age was low (before puberty = 20, after puberty = 9). This is consistent with very mild aggressive behaviours being observed in a small number of animals and is, therefore, of questionable concern. The results suggest that, for Labrador and Golden Retriever crossbreed bitches, neutering before or after puberty has little to no effect on future behaviour. It is recommended that decisions about the timing of neutering are not informed solely by impacts on behaviour, but that they also consider evidence relating to the impacts on bitch health and well-being.

WSAVAguidelines for the control of reproduction in dogs and cats

“…Retrospective studies investigating the effect of gonadectomy on behaviour are often confounded since important factors like age at gonadectomy, environmental factors and history of the individual dog are sometimes not considered, and a control group is frequently missing (Arlt et al, 2017). Confounding factors in questionnaire-based studies may be subjective interpretation of behaviour, lack of experience and ignorance of dog behaviour and body language (Moxon et al, 2022). This may contribute to the fact that some studies report no effect and others detrimental effects following gonadectomy (Kim et al, 2006;McGreevy et al, 2018;O'Farrell & Peachey, 1990;Spain et al, 2004aSpain et al, , 2004b.…”

“…The results of behavioural studies based on questionnaires are often difficult to evaluate as owners may be unable to distinguish between different types of aggression (Maarschalkerweerd et al., 1997). Further confounding factors may be subjective interpretation of behaviour, lack of experience and lack of knowledge of dog behaviour and body language (Moxon et al., 2022). Age at gonadectomy might be important in certain cases of aggressive behaviour, with earlier operation preventing an increase in learned unwanted behaviour that cannot be influenced by later gonadectomy or hormonal therapy (Heidenberger & Unshelm, 1990).…”

“…Furthermore, there was a breed effect; golden retrievers and Labradors were less likely to be dismissed for behaviour problems from the training programme than other breeds. In a recent prospective cohort study, prepubertally gonadectomised Labrador and golden retriever crossbreed female dogs were more likely to develop mild aggressive behaviour between 1 and 3 years of age than female dogs gonadectomised after puberty; however, this only occurred in 20/155 prepubertally gonadectomised female dogs and was not statistically significant (Moxon et al., 2022). A recent literature review found a lack of evidence between gonadectomy before and after puberty and behaviour problems (Moxon et al., 2023).…”

Prepubertal Use of Long-Term GnRH Agonists in Dogs: Current Knowledge and Recommendations

“…A recent cohort study showed that female Labradors and Golden Retrievers, neutered before puberty, were more likely to have aggression factor scores that increased between the 1st and 3rd year of life; however, only a small number of bitches displayed only mild aggressive behaviors. There was no impact of pre- or post-pubertal neutering on other behavioral factors [ 38 ].…”

Clinical Use of Long-Term GnRH Agonist in Prepubertal Bitches: Effect on P4, E2 and Melatonin Serum Concentration before and During First Estrus

“…For many years, surgical castration was the only reliable and permanent method of contraception in dogs. Ovariectomy, ovariohysterectomy (OHC) and orchidectomy are the most common surgical procedures routinely performed in small animal practice [1,2]. Prepubertal ovariectomy (or OHC) is defi ned as the surgical castration of immature female animals between 6 to 14 weeks of age, and it is often associated with some long-term behavior and health effects [3][4][5][6].…”