Salivary Cortisol, Equine Characteristics, and Management Factors Associated With Strongyle-Type Egg Shedding of Ohio Horses.

The research article presents a study on factors influencing parasite infection in horses, including management practices, horse attributes, and salivary cortisol levels. The findings suggest that older horses, those with certain cortisol concentrations and a high frequency of pasture mowing are less likely to have strongyle-type egg infestations.

Research Methodology

• The primary goal of the research was to identify correlation between horse management techniques, equine attributes, and salivary cortisol levels, and strongyle-type egg shedding levels in horses. The research is critical as finding such associations could help in reducing the frequency of anthelmintic administration, thereby slowing down the development of anthelmintic resistance.
• A total of 200 horses from Ohio were selected for the study. Their saliva and fecal samples were collected to analyze for cortisol and egg count. The study also administered questionnaires to barn managers to gather data about horse management practices.
• The egg count in fecal samples was performed using a modified Stoll method, while the salivary cortisol was analyzed using an enzyme-linked immunosorbent assay (ELISA). The study considered 24 variables for potential association with fecal egg count results.

Data Analysis and Findings

• The study categorized the horses into three groups based on cortisol levels – low, medium and high. Then, it performed various statistical tests, including chi-square test of independence, Fisher’s exact test, independent t-test, or Mann Whitney U test, for analyzing the correlation between these groups and the fecal egg count.
• Based on statistical analysis, variables with P < .30, i.e., those that were statistically significant predictors of egg count, were further analyzed using multiple logistic regression. The final regression model included horse age, salivary cortisol concentration, and pasture mowing frequency.
• The study concluded that older horses, those with high cortisol concentrations, and horses managed with a weekly mowing frequency of pastures were less likely to have strongyle-type egg infestations. The adjusted odds of egg count being below 50 EPG (Eggs per gram) were higher for these horses.
• The findings help in identifying strategies for managing horse infection and may contribute to providing clues regarding the onset of anthelmintic resistance. Understanding these factors could be instrumental in the development of relevant preventive measures.