Udder cleft dermatitis and hock lesions in dairy cows - animal welfare problems in great need of preventive actions

Background and aims
Udder cleft dermatitis (UCD) and hock lesions (HL) are skin lesions that can affect dairy cows. In Sweden, some smaller studies indicate that UCD and HL probably are rather common but that the proportion of affected cows vary between herds. It is likely that the skin lesions cause pain and discomfort which is negative for animal welfare. It is also possible that the lesions may be infected with bacteria and lead to increased risk for other diseases such as mastitis (udder inflammation). Unfortuately, UCD and HL have got little attention and not so much have been done to prevent these lesions. For UCD this can be due to difficulties to detected them. Preventive activities are also inhibited by the fact that the understanding of why UCD and HL occurs is limited. The overall aim of the project was to find out how common UCD and HL are in Swedish dairy cattle herds and why they develop. We also wanted to understand the connection between these lesions and mastitis. 

Conclusions
The studies showed that both UCD and HL are common among Swedish dairy cows, but that most cases are categorized as mild. It was clear that the occurrence varies between herds. Only around one third of the UCD cases recovered spontaneously and those that did were mainly mild and cases with short duration. Treatment with wound spreay did not have any effect on the recovery. Several risk factors for occurrence and developmentof UDS and HL were identified, which can be used to give better advice on how to prevent these lesions. The causes of UCD are, hwoeber, still partly not known. Thus, more studies are needed to understand how and why they develop.