Area of hock hair loss in dairy cows: risk factors and correlation with a categorical scale.

Data from 3691 dairy cows from 76 farms were used to investigate the risk factors associated with the area of hair loss over the lateral aspect of the hock and the correlation between the area of hair loss (as calculated using a hock map) and hock lesion scores determined using a pre-existing categorical scale. Six factors were associated with a greater area of hair loss, including cows with locomotion score 3, a cleanliness score (10/28 to 18/28), high daily milk yield (25.1-58.1 kg), poor body condition score (1-1.5), duration of winter housing (≥41 days) and some combinations of cubicle base and bedding materials. Compared with cows housed in cubicles with a concrete base and whole straw or rape straw bedding, cows housed in cubicles with concrete bases with sand or chopped straw bedding had smaller areas of hair loss and cows housed on a mattress base with whole straw or rape straw bedding had larger areas of hair loss. Area of hair loss, as measured on hock maps, was not significantly different between cows with score 1 (median 23.6 cm(2)) and score 2 (median 20.3 cm(2)) on the categorical scale for hock lesions. This suggests that the categorical scale was not reflecting the extent of hair loss and that hock maps are a good alternative for studying the dynamics of hock lesions over time.

Prevalence and characterisation of, and producers' attitudes towards, hock lesions in UK dairy cattle.

The objectives of this paper were to characterise lesions found at the hock and to establish their prevalence across a large sample of dairy cows in the UK. In addition, the study aimed to examine farmers' perceptions of these lesions. Seventy-seven farms were visited; both hocks on a random sample of approximately 50 cows were scored on a categorical scale for hair loss, ulceration and swelling. In addition, the size and location of lesions were marked on a hock map. A questionnaire designed to explore attitudes towards lesions was conducted with the owner. Hair loss and ulceration were seen at five locations. Hair loss was identified on 5,619 of 6,896 hocks (mild: 43.7 per cent; moderate: 25.1 per cent; severe: 12.6 per cent) and 1,137 of 6,896 hocks had areas of ulceration (mild: 8.6 per cent; moderate: 5.8 per cent; severe: 2.1 per cent). The majority of lesions were small; however, a small proportion had extensive areas of hair loss (maximum size 113.3 cm2) and ulceration (maximum size 95.5 cm2). Moderate swelling was recorded on 20 per cent of hocks, and 2.0 per cent had severe swelling. Interview results suggested that more than 90 per cent of participants were aware of hock lesions and a third had sought treatment for them; most felt that lesions had at least some impact on productivity and welfare.