Prevalence and severity of foot lesions in Danish Holstein heifers through first lactation.

Several studies have shown that foot lesions and clinical lameness occur before first calving and develop further during the lactation period. Lameness may cause production losses, but the relationship between foot lesions, particularly in the claw horn, and lameness in heifers is unclear. The objectives of this study were to describe the development of and evaluate the relationship between lameness and foot lesions in Danish Holsteins before and after first calving. In a longitudinal study, 147 heifers were examined for lameness and foot lesions 2-5 times over an 18-month period. Lameness was assessed by means of a visual locomotion score and foot lesion severity was recorded. The prevalence of a locomotion score 3 was 25% before calving, and 90% at approximately 250 days in milk (DIM). Prevalence of moderate to severe sole haemorrhage (SH) was 27% before calving and 56% at 250 DIM, and that of moderate to severe white line lesion (WLL) 44% before calving with a peak of 70% at 200 DIM. There was one case of white line abscess but SH was seen throughout the entire study period. Digital dermatitis (DD) was prevalent prior to first calving (15%) and peaked at 39% at 0-100 DIM. Heel horn erosion (HHE) occurred in almost all cows (93-100%) and was strongly correlated with DD (r=0.51). The correlation coefficient between SH and WLL was also high (0.42). The relatively high correlations between WLL and both DD and HHE were more surprising (0.38 and 0.35, respectively), those between SH and both DD and HHE were moderate (around 0.18). Interdigital dermatitis was significantly correlated with both HHE and DD, but completely unrelated to SH and WLL. The overall average locomotion score increased by about one-half of a score unit from 1 month prior to calving until 250 DIM, with a large difference between herds, although this was unsurprising as cows may alter their locomotion pattern with management factors (e.g. floor properties). DD and WLL were both associated with a locomotion score > or = 3 but of the cows with severe WLL there was no clear association between a locomotion score > or = 3 and DD. The highest locomotion scores occurred among cows with DD but without WLL.