Tail Lesions in Dairy Cows - What´s new about the old?

Tail tip inflammation is a well-known and widespread problem in fattening bulls. In addition to housing conditions, the main causes are thought to be the influence of feeding in the form of lack of structure or mycotoxin contamination. Recent studies show that dairy cows are also affected by alterations of the tail tips. In a first phase of our studies, different types of alterations in the invertebrate tail end of dairy cows were described. Based on these observations, dairy cows from numerous other farms were examined. Prevalences of up to 99% were found on all farms. Histopathologic examination of the tail ends of affected cows at slaughter revealed coagulation necrosis in deeper layers with undamaged epidermis. Coagulation necrosis occurs as a result of circulatory disturbances and could therefore be a possible cause of the observed changes. These results are in accordance with previous findings on the pathogenesis of hemorrhagic tail lesions, since thermographic examinations of the tail ends have shown that there is a clear correlation between the surface temperature of the tail ends, animal health, and the frequency of alterations at the tail end. Studies in calves have also shown that they were born with intact tail tips. However, weekly scored calves showed a strong accumulation of bloody lesions at the tail tips after dehorning in the third week of life, as well as after other triggers such as weaning from milk or first feeding of a cow TMR. In addition, significant correlations were found between the occurance of tail tip alterations in dairy cows and the day of lactation, number of parturitions, body condition and milk components. Thus, a purely traumatic origin caused by treads from other animals, manure scrapers or slatted floors seems rather unlikely. In principle, severe lesions such at the tail tip can be expected to be painful and represent, among other things, a potential source of infection and therefore, represent an animal welfare issue. Studies from Denmark or New Zealand also describe similar changes with high prevalences. Severe alterations, including (auto-)amputation of parts of the tail, may therefore be a worldwide phenomenon with an internal cause in high yielding cows.