Abstract
Problem behaviours are a leading cause of relinquishment and euthanasia of young dogs. Previous research has identified associations between owner-reported problem behaviours and risk factors, including how dogs were acquired as puppies, early socialisation experiences, and owners' experience levels. Puppies acquired during the 2020 phase of the UK COVID-19 pandemic ("Pandemic Puppies") were more likely to be exposed to many of these risk factors compared to puppies acquired in 2019; however, consequences for their adult behaviour are, as yet, unexplored. This study aimed to investigate the impact of these early-life and provenance-based risk factors, in addition to owner management strategies (including training methods) into early adulthood, upon adult dog behaviour aged 21 months. An online longitudinal cohort study of n = 985 Pandemic Puppies was conducted, recruited from a cohort of n = 4369 puppies originally surveyed in November-December 2020, which included data on how and why they were acquired and their socialisation/habituation experiences <16 weeks of age. Nearly all owners (96.7%) reported that their dog had exhibited at least one problem behaviour up to 21 months of age (median: 5; IQR: 3-7). Almost one third of dogs (30.9%) were reported to have displayed separation-related behaviours. Multivariable linear regression modelling revealed that owners reporting more problem behaviours were more likely to use multiple aversive training techniques (e.g., physical punishment), the use of which was notably high in this population (82.3%) compared to previous studies. Attendance at online puppy classes was the sole protective factor against owner use of aversive training methods. Almost one third of owners had underestimated how hard training their dog would be; this view was more likely among first-time owners. Urgent efforts are required to support this vulnerable population of dogs, including providing owner education regarding humane training techniques, to improve canine emotional health and avoid future relinquishment and/or behavioural euthanasia.