Short communication: A comparison of cow cleanliness, fly population, and fly avoidance behaviors among docked, switch-trimmed, and switch-intact dairy cows in 3 commercial dairy herds.

Tail docking is a controversial practice in the dairy industry. Proponents claim that tail docking keeps the udder cleaner, and therefore improves milk quality and decreases somatic cell count. Opponents of tail docking cite that it causes unnecessary pain, backed by multiple studies that demonstrate no positive benefits of tail docking and that tail docking increases aggravation from flies. The objective of this study was to evaluate and compare cow cleanliness, fly population, and fly-avoidance behaviors among cows with docked, switch-trimmed, and switch-intact tails. A total of 206 cows from 3 Kentucky dairy herds were included in the longitudinal observational study. Each farm included previously docked cows, switch-intact cows, and cows whose switches were trimmed at the initial farm visit. Researchers visited each farm every 2 wk for 8 wk to record cow cleanliness, teat cleanliness, fly population, and fly-avoidance behavior scores. No significant differences were found in cow cleanliness scores, teat cleanliness scores, fly population scores, skin twitching, or foot stomping counts among docked, switch-trimmed, or switch-intact cows. Although the fly population scores did not differ, the amount of tail swings among docked, switch-intact, and switch-trimmed cows were significantly different. The odds of exhibiting tail swinging were 2.63 times greater for docked cows than for switch-trimmed cows and 1.92 times greater than for switch-intact cows. Overall, switch trimming resulted in similar outcomes to tail docking, although neither showed improvements over intact tails.