Large Animal Monday Schedule
Equine Asthma: Diagnosis & Therapy
Dr. Rebecca Legere, DVM, MS, PhD, DACVIM-LA
Equine asthma (also known as recurrent airway obstruction [RAO], chronic obstructive pulmonary disease [COPD], or heaves) is a chronic inflammatory airway disease characterized by reversible airway obstruction and mucus accumulation. Disease presentation varies from exercise intolerance with the mild-moderate phenotype to chronic cough and labored breathing with severe asthma. Equine asthma is primarily managed through environmental modifications to reduce exposure to airborne triggers and anti-inflammatory therapy to manage the pulmonary response to triggers. Bronchoconstriction, excessive mucus production, and coughing are secondary to inflammatory cascades and are managed with bronchodilators, mucolytics, and antitussive therapies as well as reducing inflammation. This talk will focus on current understanding of clinical presentations, diagnostic testing, and management strategies for equine asthma.
Nebulizer Therapy for Large Animals
Dr. Rebecca Legere DVM, MS, PhD, DACVIM-LA
Nebulizers are used extensively in large animal medicine for treatment and management of asthma, pneumonia, and other indications. It is important to consider nebulized therapy as the outcome of a 4-component system: 1) Drug, 2) Nebulizer device, 3) Spacer/mask, and 4) Patient. Each of these components contributes to the overall drug delivery and efficacy, as well as patient and user safety. This talk will focus on the benefits and limitations of nebulized drug delivery in large animal medicine, and areas for ongoing research to optimize this modality.
Rhodococcus equi: Diagnosis & Management
Dr. Rebecca Legere DVM, MS, PhD, DACVIM-LA
Rhodococcus equi (R. equi) is an important opportunistic pathogen in young horse foals worldwide, and it can also cause disease in other veterinary species and humans as a zoonotic agent. This facultative intracellular bacterium is ubiquitous in the environment at horse farms, primarily in soil and manure. Foals are infected in the first days and weeks after birth when they are most susceptible to infection due to naïve and immature immune responses. The most common clinical presentation is severe pyogranulomatous pneumonia following an insidious, slow progression of disease; treatment requires prolonged antimicrobial therapy and supportive care. The costs and labor associated with monitoring, prevention, treatment, lost foals due to death, and reduced athletic performance in recovered foals makes this disease of great concern for the equine industry and for horse welfare. Despite years of efforts, no safe and effective vaccine is available and emergence of antimicrobial-resistant strains of R. equi threatens long-term efficacy of available treatment modalities. This has created great need to prevent rhodococcal pneumonia and reduce burden of disease at endemically affected farms. This talk will focus on diagnosis and management of R. equi in individual foals and herd settings.
Updates and Advances in Diagnostics and Therapeutics for Equine Tendon/Ligament Injuries
Dr. Sushmitha Durgam, PhD, BVSC, DACVS-LA
Tendon and ligament injuries are among the most common sources of poor-performance and lameness dealt with by equine veterinarians. Given the increasing use of advanced imaging, particularly MRI, and biologic therapies and rehabilitation, there has been significant progress towards accurate diagnosis and implementing therapies in equine practice. The goal of this presentation is to review the specialized structure of equine tendons and ligaments highly prone to clinical injuries, highlight the existing and upcoming diagnostic and treatment modalities aimed at timely intervention while discussing evidence-based practices to enhance the clinical outcomes in our equine patients.
How to Perform and Interpret Liver Biopsies in Cattle
Dr. Scott Fritz, DVM, PhD, DABV
Liver biopsies are a useful and practical tool for evaluating trace mineral status in cattle. Getting a number is the easy part, interpreting what that number means can be more challenging. This presentation will review practical aspects of performing liver biopsies in cattle and focus on how biopsy results should be interpreted in the context of herd history, geography, and production stage.
System Thinking and Early Calfhood Disease
Dr. Todd Gunderson, DVM, MS, ACVPM (epidemiology)
Early calfhood is a challenging time for cows, calves, producers, and the veterinarians who are charged with their care. Neonatal calves are susceptible to a host of enteric and respiratory diseases that often manifest with little warning, may be difficult to treat, and can result in severe losses. Traditional mental models for preventing early calfhood disease tend to focus on a pathogen-centric, or ‘bugs and drugs’ focused, paradigms for prevention and treatment of early calfhood disease. This presentation uses examples from clinical practice, including outbreaks of bovine coronavirus and Cryptosporidium parvum, to challenge that reductionist lens and introduce systems thinking as a complementary framework. Placing emphasis on differentiating between necessary and sufficient causes, this talk will explore the structure of calfhood disease using causal loop diagrams and systems archetypes. These models illustrate how individual components such as pathogen amplification, environmental contamination, immunity, and management structure interact to produce predictable outcomes. Practical, delay-based interventions (e.g., pen rotation intervals shorter than incubation periods, minimizing cross-contamination, strategic animal flow) are proposed as structural modifications rather than reactive ‘patches’. Reframing early calfhood disease as a systems outcome offers veterinarians a more durable, management-focused approach to preventing outbreaks, optimizing labor, and rearing healthier, more productive cattle.
Beyond Bugs and Drugs: What I wish I’d Known About Disease Outbreak Investigation When I Was in Practice
Dr. Todd Gunderson, DVM, MS, ACVPM (epidemiology)
Investigating outbreaks of disease in production animal systems can be a daunting and frustrating endeavor for producers and veterinarians alike. Predictably, producers’ immediate concerns often center on vaccine failure and the availability of additional preventive or therapeutic injections, reducing investigations to a search for a causative pathogen and an accompanying pharmaceutical solution (i.e., the ‘bugs and drugs’ approach). This presentation walks through the core steps of outbreak investigation: establishing the existence of an outbreak, verifying the diagnosis (including test characteristics and pre-test probability), constructing a case definition, and conducting descriptive epidemiology through epidemic curve development. Emphasis is placed on distinguishing endemic, point-source, and propagating patterns. Participants are guided through hypothesis generation and testing using appropriate study designs such as case series, case-control, cohort, randomized trials, while avoiding common cognitive traps such as regression to the mean, confirmation bias, and confounding. Developing primary, secondary, and tertiary prevention strategies that avoid knee-jerk management changes and implement key changes over time using systems thinking, structured follow-up, and proactive communication is also discussed. Implementing these principles will enable practitioners to develop a disciplined, systems-informed framework for outbreak investigation that improves decision quality and long-term herd outcomes.