The influence of fly prevalence on fly dislodging behaviors of dairy cows

Abstract

Fly infestation is a significant problem for dairy farms. The aim of our work was to study changes in cow behavior at different levels of fly infestation. The study was conducted on a dairy farm with an average annual milk yield per cow of about 8,000 kg. The intensity of infestation and fly defense behavior of cows was studied in March (low intensity of infestation) and July (high intensity of infestation). It was found that the intensity of fly infestation in March was 0.7±0.21 (n=25), in July - 38.4±2.39 (n=25) flies per cow. At low intensity of fly infestation, cows made only one movement by one of the body parts. At high intensity of fly infestation, cows standing near the feeding table made 21.6±0.84 tail switching, 9.1±0.61 skin twitching, 2.59±0.2 head tossing, and 2.59±0.24 and 2.29±0.19 pelvic and thoracic foot movements per minute, respectively. During milking, cows threw their heads less (0.6±0.12 moves/min, p<0.001), compensating for this with more forelimb stomps (3.4±0.2 strokes/min, p<0.001) and skin twitching (17.2±1.12 moves/min, p<0.001). Fly swatting movements in lame cows are 1.7-4.6 times less frequent than in healthy cows, indicating the development of the “acquired helplessness” syndrome.