Background: Despite extensive research, many questions remain unanswered about common problems that impact dog welfare, particularly where there are multiple contributing factors that can occur months or years before the problem becomes apparent. The Generation Pup study is the first longitudinal study of dogs that recruits pure- and mixed-breed puppies, aiming to investigate the relative influence of environmental and genetic factors on a range of health and behaviour outcomes, (including separation related behaviour, aggression to familiar/unfamiliar people or dogs and obesity). This paper describes the study protocol in detail. Methods: Prior to commencing recruitment of puppies, the study infrastructure was developed, and subject specialists were consulted to inform data collection methodology. Questionnaire content and timepoint(s) for data collection for outcomes and potential predictors were chosen with the aim of providing the best opportunity of achieving the aims of the study, subject to time and funding constraints. Recruitment of puppies (< 16 weeks, or < 21 weeks of age if entering the United Kingdom or Republic of Ireland through quarantine) is underway. By 23 January 2020, 3726 puppies had been registered, with registration continuing until 10,000 puppies are recruited. Data collection encompasses owner-completed questionnaires issued at set timepoints throughout the dog’s life, covering aspects such as training, diet, exercise, canine behaviour, preventative health care, clinical signs and veterinary intervention. Owners can elect to submit additional data (health cards completed by veterinary professionals, canine biological samples) and/or provide consent for access to veterinary clinical notes. Incidence and breed associations will be calculated for conditions for which there is currently limited information (e.g. separation related behaviour). Multivariable statistical analysis will be conducted on a range of outcomes that occur throughout different life stages, with the aim of identifying modifiable risk factors that can be used to improve canine health and welfare. Discussion: The Generation Pup project is designed to identify associations between early-life environment, genotypic make-up and outcomes at different life stages. Modifiable risk factors can be used to improve canine health and welfare. Research collaboration with subject specialists is welcomed and already underway within the fields of orthopaedic research, epilepsy, epigenetics and canine impulsivity.

A random sample of 2980 households in the UK in 2007 showed that 26 per cent and 31 per cent of households owned cats and dogs, respectively. Households with gardens were more likely to own cats and dogs than households without gardens. Households in which someone was qualified to degree level were more likely to own cats and less likely to own dogs than other households. Cats were more likely to be owned by semi‐urban/rural households and by female respondents. Dog ownership significantly decreased the likelihood of cat ownership, and respondents aged 65 years or more were less likely to report that their household owned a cat than younger respondents. Households with one or more dogs and children aged 11 to 15 years were more likely to own a cat than other households. The likelihood of dog ownership increased as household size increased. Dogs were more likely to be owned by rural households, and less likely to be owned by households with cats or children aged 10 years or younger. Female respondents and those aged less than 55 years were more likely to report dog ownership than other respondents. The estimated size (and 95 per cent confidence intervals) of the owned cat and dog populations in the UK in 2006 was 10,332,955 (9,395,642 to 11,270,269) cats and 10,522,186 (9,623,618 to 11,420,755) dogs.

The main aim of this study was to replicate methodology used to estimate the size of the UK pet cat and dog populations in 2006 and the proportion of households owning cats/dogs in 2007, to produce updated data to compare trends in ownership and population sizes. A cross‐sectional study design was used to collect telephone interview data from 3155 households in the UK. 2011 UK human census data were used to predict the size of the cat and dog populations owned by households in the UK in 2011. Of the households, 23 per cent (714/3155) owned one or more cats and 30 per cent (940/3155) owned one or more dogs. There was some overlap in pet ownership with 7 per cent (210/3155) of households owning both one or more cats and one or more dogs. There was a small but significant decrease in the proportion of households that owned one or more cats in 2011 compared with 2007, with no change in the proportion owning dogs. However, overall, the total number of cats and dogs that were estimated to be owned by UK households did not change significantly between 2006 and 2011. The estimated size (and 95% CIs) of the pet cat and dog populations in the UK in 2011 was 10,114,764 cats (9,138,603–11,090,924) and 11,599,824 dogs (10,708,070–12,491,578).

It is not known how many cats and dogs are admitted to welfare organisations annually. This study produced the first estimates of the size of this population. A questionnaire was mailed out to welfare organisations during 2010, followed by a postal/email reminder and requests to non‐responders for a telephone interview. The questionnaire covered areas including, the current number of cats and dogs being housed, how much of the year organisations were operating at full capacity as well as the number of cats and dogs admitted, rehomed and euthanased between January and December 2009. Responses were obtained from 54.8 per cent of organisations. Sixty‐six per cent of cat welfare organisations and 48 per cent of dog welfare organisations reported that they operated at full capacity for 12 months of the year. The number of cats and dogs entering UK welfare organisations during 2009 was estimated as 131,070 and 129,743, respectively. This highlights the scale of the work performed by welfare organisations in caring for and rehoming unwanted cats and dogs annually and emphasises the urgent need to address concerns over the considerable number of these animals. This study has also produced useful baseline data, which will be essential for monitoring population changes over time.