Effect of Equine Flysheets on Fly Avoidance Behaviors, Body Temperature, Stress Level, and Heart Rate

Background: Flysheet use is common without any published scientific evidence to justify their use. Objectives: To demonstrate the effectiveness of flysheets at reducing fly avoidance behaviors and measure changes in body temperature, heart rate, or cortisol levels. Study design: 10-week alternating crossover design Methods: 6 horses were divided into two groups. Flysheets were alternated between groups weekly for 10 weeks. Fly avoidance behaviors were recorded for 30-minutes once weekly. Cortisol samples were collected before flysheet application or removal, and again 10 minutes later. Star-Oddi data loggers recorded heartrate and temperature every 15 minutes throughout the study period. Results: Flysheet use significantly reduced fly avoidance behaviors. Mean head tosses decreased from 12.17 (95% CI: 17.58–6.76) to 2.33 (95% CI: 0.64–4.02) (p