Avian pathogenic Escherichia coli (APEC) is the causative agent of avian colibacillosis, a localised or systemic infection resulting in clinical diseases such as colisepticemia, chronic respiratory disease and swollen-head syndrome. Globally, avian colibacillosis is the leading cause of morbidity and mortality in poultry, and it has been associated with massive economic losses and welfare problems.This organism is of public health significance as APEC is communicable to humans. The diagnosis of avian colibacillosis relies on clinical signs, typical pathological lesions and culture of E. coli from affected tissue(s). Antimicrobial therapy is often used both for treatment and control. Previous overseas studies have characterised APEC and identified virulence genes (VGs) that can be used as molecular markers for the identification of APEC. Little is known about APEC in broiler chickens in Australia.The aim of this thesis was to gain a better understanding of the epidemiology of APEC in Australian broiler flocks and how factors including presence of VGs and phylogenetic group can improve the identification of this pathotype in Australia. Firstly, three faecal DNA extraction methods were evaluated. Faeces were collected from healthy chickens and chickens with colibacillosis from commercial broiler farms in South East Queensland (SEQ). The extracted DNA was screened by a pentaplex-PCR for five APEC-associated VGs (iroN, iutA, iss, hlyF and ompT). DNA extracted from E. coli isolates cultured from the cloaca and organs of the birds were screened using the same PCR.Repeated bead beating plus column elution was the preferred DNA extraction method, as it yielded good PCR quality and adequate quantity DNA. However, identifying APEC by direct detection of the five VGs from the faecal material was not feasible as all of these genes were also detected in all of the birds. However, the VGs were more commonly detected in E. coli isolates cultured from birds with colibacillosis.A cross-sectional study was performed to estimate APEC farm-level prevalence in healthy broiler chickens in SEQ and to identify potential risk factors associated with the carriage of APEC. At the farm-level, all of the 40 farms sampled were positive for APEC, that is at least one bird per farm carried APEC, while the within-farm prevalence was 63% (95% Confidence Interval: 55.8, 70.2).Higher APEC within-farm bird-level prevalence was significantly associated with the usage of well water as a source of drinking water, failure to disinfect the water line after each flock, farm visitors not showering before entering the shed, distances greater than 20 metres between the car park and the poultry shed and the presence of wild birds within 50 metres of the shed. Chlorinating the drinking water combined with automatic water filtration reduced within-farm bird-level APEC prevalence. Page | 3Therefore, based on the results concluded from the multivariable model, improving biosecurity and water treatments might reduce APEC prevalence, decrease the risk of co...

One in four New Zealand cats are overweight or obese, conditions associated with poor health outcomes. As part of an online survey that was conducted from January 2019 to March 2019, NZ residents aged ≥18 years were asked demographic questions along with questions related to the body condition, breed and diet of their cat/s. From the responses, possible owner-related risk factors for developing obesity were identified. Of the respondents, 65.5% (n = 1537) owned cat/s; the owners being more likely to be female, live rurally, or live with children. Most of the respondents fed their cat/s biscuits from the supermarket (63%) and wet food (57%). Almost half (45%) fed their cat/s specialised food from a pet shop or veterinary clinic and gave them treats, with 31% of respondents feeding their cat/s raw meat. Feeding cats a variety of food types may make it difficult to estimate the appropriate amount of each needed to avoid excess caloric intake. In addition, approximately 30% of the respondents did not agree with the correct body condition statement, revealing a need for owner education. These findings highlight important areas of cat nutrition requiring future research to better inform the development of healthy weight interventions for NZ cats.

Bovine trichomoniasis, caused by the protozoal parasite Tritrichomonas foetus, is a highly contagious venereal disease characterised by early pregnancy loss, abortion and pyometra. Persistently infected bulls and cows are the primary reservoirs of infection in infected herds. This research investigated the prevalence of T. foetus infection in bulls from properties located across northern Australia and New South Wales. Preputial samples were collected from 606 bulls at slaughter and tested for T. foetus using the VetMAX-Gold Trich Detection Kit (Thermo Fisher Scientific). The apparent prevalence of T. foetus infection varied between regions, with northern regions in the Northern Territory, Queensland and Western Australia showing a prevalence of 15.4%, 13.8% and 11.4%, respectively. There was some evidence of an association between infection and postcode (P = 0.06) and increasing bull age (P = 0.054). This study confirms that T. foetus infection is likely to be present in many beef breeding herds and contributing to lower than expected reproductive performance, particularly across northern Australia.

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Approximately a third of all Aotearoa New Zealand (NZ) households include a dog, with 28% of these dogs being overweight or obese, conditions that are associated with many serious health issues. Therefore, healthy weight interventions that focus on the owner’s role are of great importance to companion animal welfare in NZ. Accordingly, the present study explores the feeding practices associated with NZ dogs and identifies potential owner-related risk factors contributing to these animals being overweight or obese. The current study used data collected from a survey conducted online in 2019 between January and March of NZ residents over 18. Along with demographic questions, the respondents were asked questions regarding their dog’s body condition and diet questions related to the body. Nearly a quarter (26%, n = 609) of the survey participants (n = 2358) owned at least one dog. The current study reported that increasing age range, household income and the number of children increased the likelihood of having a dog while increasing qualification level and living in a town/city decreased the likelihood. The majority of the respondents fed their dog(s) treats (59%) and 85% fed them specialised food bought from a pet shop, veterinary clinic and/or different online sources. Just over a third of the participant (39%) reported that they fed their dog(s) biscuits from the supermarket, 36% fed their dog(s) raw meat, and 34% of respondents fee their dog(s) table scraps/human food. These results suggest that many dog owners feed their dog(s) various food types, making it a challenging task to determine the exact amount required from each type in order not to exceed caloric intake. Disagreement regarding the correct body condition were reported among twenty per cent of the respondents. This finding indicates a knowledge gap among the NZ dog-owning population that may negatively affect their dogs’ welfare and wellbeing. Future research into pro-equity approaches to address these issues is needed so that dogs in NZ can live not only a good life but also their best life.

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Avian pathogenic E. coli (APEC) can cause avian colibacillosis, an economically important disease that contributes to bird mortality and the high costs associated with prevention and treatment. Little is known about APEC in the context of Australian conditions. The current study aimed to estimate the prevalence of APEC and determine the risk factors associated with cloacal carriage of APEC among commercial healthy meat chickens in Queensland. Cloacal swabs were collected at slaughter from 400 healthy meat chickens (ten per farm) originating from 40 farms. A total of 2200 E. coli isolates were selected from cultured swabs and screened for the presence of five APEC-associated virulence genes (VGs). Farm-level data were collected using a questionnaire. Binominal general linear models were used to identify farm-level risk factors associated with bird-level APEC prevalence. Thirty-four per cent of the cultured E. coli isolates (n = 751) were classified as APEC, with all farms testing positive for APEC, and the overall bird-level prevalence of APEC was 63.0%. Higher APEC within-farm bird-level prevalence was positively associated with the usage of well water as a source of drinking water (OR = 6.2, 95% CI: 2.3, 16.5, p < 0.001); not having shower facilities available for farm visitors (OR = 3.6, 95% CI: 1.8, 7.1, p < 0.001); distances greater than 20 m between the car park and the poultry shed (OR = 2.2, 95% CI: 1.4, 3.4, p = 0.001); not applying water line disinfection after each flock cycle (OR = 2.2, 95% CI: 1.4, 3.5, p = 0.001); the presence of wild birds within 50 m of the poultry shed (OR = 2.3, 95% CI: 1.4, 3.7, p = 0.001). Chlorine combined with automatic drinking water filtration reduced within-farm bird-level APEC prevalence (OR = 0.07, 95% CI: 0.02, 0.34, p = 0.001). This study identified a number of important factors associated with APEC and showed that improving biosecurity and water treatments might reduce the prevalence of APEC. The notable high APEC prevalence on all farms requires further epidemiological investigations.

This study used an online survey distributed between January and March 2019 to adults residing in Aotearoa New Zealand (NZ) to investigate cat and dog owner practices. Of the 2385 respondents, 885 (37%) owned both cat/s and dog/s, while 652 (28%) and 609 (26%) owned cat/s only or dog/s only, respectively. Nine percent of respondents (n = 212) did not own a cat or dog when the survey was administered. Gaps were identified in the practices of NZ pet owners with regard to regular grooming, immunizations, and deworming treatments. It was also found that many pets, especially cats, were allowed to wander freely both inside and outside the house. Collectively, these gaps in practice raise parasitology and infection concerns which may impact negatively on animal welfare and may increase the prevalence of zoonotic diseases. This study also revealed the need to improve desexing practices, particularly in dogs. Respondents in the survey expressed the wish to have pets regardless of the financial strain they may impose, indicating that future research should focus on reducing the financial burden of pet ownership along with promoting positive pet ownership practices. Our findings suggest the need for better education resources about pet ownership which are easily accessible and target diverse populations. The findings of this study will aid in developing appropriate educational resources to promote animal welfare and increase pet-related knowledge among the NZ populace.