Table of Contents and Abstracts

The objectives of this multicenter, retrospective study were to: i) describe the incidence of gallbladder (GB) rupture in small-breed dogs affected by gallbladder mucoceles (GBM) and common endocrinopathies; and ii) determine if certain endocrinopathies were risk factors for GB rupture as they have been for the development of GBM. A total of 371 dogs were included in the study. Medical records from private specialty hospitals were reviewed for small-breed dogs undergoing cholecystectomy for GBM. Forty-seven of 193 dogs (24.4%) with endocrinopathies were diagnosed with GB rupture. Mortality due to GB rupture was 23.9%. Dogs with GB rupture were 3.2 times more likely to die than dogs without rupture (P < 0.001). Dogs with overall concurrent endocrinopathies, hypothyroidism, and pancreatitis were 2.5, 4.1, and 2.6 times (P = 0.001, 0.001, 0.002) more likely to develop a GB rupture and 2.6, 4.4, and 2.8 times (P = 0.008, 0.013, 0.011) more likely to die than dogs without concurrent endocrinopathies. Dogs with hyperadrenocorticism were not associated with a higher risk of GB rupture (P = 0.114) or death (P = 0.321). It was concluded that elective cholecystectomy should be considered in dogs with GBM and concurrent endocrinopathies, especially hypothyroidism and pancreatitis, to lower the risk of gallbladder rupture and death.

Vaccination is the most efficient tool for preventing West Nile virus (WNV) disease in horses. The objectives of this retrospective study were to: i) estimate the provincial and national horse population in Canada; ii) estimate the annual vaccination coverage for WNV in each province; and iii) compare estimates of provincial annual vaccination coverage. Horse population data (2006–2023) and the number of vaccine doses sold in Canada (2016–2020) were obtained by province. Based on these data and expert consultations, the annual number of vaccine doses administered, and provincial horse populations were modeled at the provincial level using Program Evaluation and Review Technique (PERT) distributions, whereas the probability of primary vaccination in vaccinated horses was modeled with a uniform distribution. The annual number of horses vaccinated was estimated using a binomial distribution. Monte Carlo simulations were used to estimate provincial annual vaccination coverage with 95% credible intervals (CI). National horse population and vaccination coverage were estimated by summing the provincial estimates. The national horse population in Canada (2016–2020) was estimated at 795 420 horses, with a vaccination coverage of 16% (95% CI: 13 to 20%). The vaccination coverage estimates for WNV ranged from 10% (95% CI: 6 to 20%) in the Atlantic provinces to 35% (95% CI: 22 to 53%) in Manitoba. The coverage was significantly higher (P ≤ 0.01) in Manitoba than in the Atlantic provinces, Saskatchewan, Alberta, and British Columbia. The study revealed low annual WNV vaccination coverage across Canada, emphasizing the need to promote vaccination and collect more comprehensive data on horse population, as uncertainties in these data drive the uncertainty in vaccination coverage based on model sensitivity analysis.

Swine production in Ontario, Canada relies on national and international borders remaining open to both live pigs and pork. The established practice is to export live pigs and surplus pork, as the number of pigs destined for processing and the quantity of pork produced in Ontario exceeds the current abattoir capacities and consumer demand in the province. In the event of a foreign animal disease (FAD) incursion resulting in processing disruptions, borders may close to Ontario’s pigs and pork products. The swine industry would then have to make changes to accommodate the resources available and the projected demand in the province. The objective of this study was to create a tool based on discrete event simulation to include swine reduction strategies in a risk-free environment. This tool was then used to investigate a subset of possible mitigation scenarios for reducing the size of swine herds and assessing the number of target animals and pork production capacities, based on known estimates of pork consumption in Ontario. Strategies to decrease the swine herd to meet target values were explored and the amount of surplus pork, surplus market hogs, and the time to reach the target numbers were recorded. Simulated data were analyzed in R and it was determined that simultaneous mitigation at all stages of production (including the sow farm) was the most efficient method of reducing the provincial herd, resulting in the lowest amount of surplus market hogs. Even though it was determined that weeks to months were necessary, using assumed resources, to achieve a self-supporting provincial pig industry that does not rely on imports or exports, the software in this study could be used to run hypothetical scenarios in order to prepare for any crisis in the Ontario swine sector and for planning purposes.

Respiratory disease is common in sheep worldwide. The objective of this study was to use real-time polymerase chain reaction (PCR) on bronchial swabs collected from sheep lungs with gross pathological signs of ovine respiratory complex (ORC) at abattoirs in southeastern Australia to detect 3 common bacterial ovine respiratory pathogens [Mycoplasma (Mesomycoplasma) ovipneumoniae, Mannheimia haemolytica, and Pasteurella multocida]. Mycoplasma ovipneumoniae was the most detected (35% of samples), followed by M. haemolytica (14.9% of samples), and P. multocida (8.1% of samples). The most common combination of infections was M. ovipneumoniae plus M. haemolytica (48 samples, 14.7% of positive samples), followed by M. ovipneumoniae plus P. multocida (21 samples, 6.4% of positive samples), and M. haemolytica plus P. multocida (19 samples, 5.8% of positive samples). There was a weak positive correlation between samples positive for M. ovipneumoniae and samples positive for M. haemolytica (r = 0.14, P = 0.002), a weak positive correlation between samples positive for M. ovipneumoniae and samples positive for P. multocida (r = 0.08, P = 0.002), and a weak-to-moderate positive correlation between samples positive for M. haemolytica and samples positive for P. multocida (r = 0.25, P < 0.001). Further research is needed on management options for ORC in Australian sheep farmed in extensive grazing systems.