BSAS conference: Hock lesions more common than thought

Research has shown that 99% of all cows have some form of hock lesion. But, unlike lameness, little research had been done into them, said Sarah Potterton of the University of Nottingham told the BSAS conference.

“Hock lesions take many forms and can include hair loss, thickened skin, wounds, scabs and swellings occurring on the tarsal joint. Cow-related factors and also possible management factors have been suggested as possible risk factors,” she said.

“The presence of hock lesions are correlated with injuries of the teat, carpal joints and skin, as well as increases in mobility score, high somatic cell counts, a greater incidence of clinical mastitis and higher culling and annual death rate. But we wanted to know the significance of potential risk factors in development of lesions.”

A sample of cows from dairy farms in the East Midlands were assessed for lesions and the severity recorded on a four-point scale. “Initial results show 89.7% of all cows showed some degree of hock hair loss, 11.8% with ulceration and 100% with some kind of hock swelling. The median percentage of hocks displaying hair loss, ulceration and swelling of score two and above (most severe) were 37%, 4.6% and 21.8% respectively,” she said.

“Of the 77 herds, most cows were housed on rubber matting or mattresses in cubicles and although not all results have been analysed, bedding and lying surfaces would probably be an important determinant,” she said.

“Although rubber mats and mattresses are increasing level of lesions, they do increase cow comfort. This is why management is important in relation to bedding. However, hock lesions have been about for many years, so it is likely other factors are involved.”