A Look Inside – Histopathological Examinations of Different Tail Tip Lesions in Dairy Cows

Feedlot cattle are frequently affected by inflammation and necrosis of the tail tips, resulting in impeded animal welfare and economic losses. In a recent study it was demonstrated that dairy cows are also affected by different lesions of the tail tip, among others alopecia, annular constrictions, crusting, scaling and swelling. Despite the frequent occurrence of these lesions, the underlying etiology and pathomechanisms are unclear to date. To gain insight into this malady, we histopathologically examined 16 tail tips of slaughtered dairy cows, representing the entire bandwith of different lesions. While macroscopically alopecic areas were characterized by the formation of granulation tissue in the dermis with unconspicuous epidermis, we found not only dermal granulation tissue but also purulent-necrotizing inflammation with breakdown of the basement membrane in encrusted lesions. Interestingly, in some cases we found herds of coagulation necrosis of epidermal and dermal layers in the crusts. Tails with macroscopical scaling were affected by ortho- and/or parakeratotic hyperkeratosis and in tails with macroscopical swelling, we observed a low-protein edema of the central longitudinal connective tissue of the tail. We conclude that the observed lesions might be caused by ischemia of the skin in distal parts of the tail.