Samband på individnivå mellan akuta klövskador och cellhalten i mjölk hos mjölkkor

Abstract: The purpose of the present study was to investigate the cow-level association between acute hoof lesions and the somatic milk cell count in dairy cattle. Cows from three loose-housed Swedish dairy herds were enrolled in the study if they had an acute hoof lesion treated by a veterinarian or professional hoof trimmer during the preceding year, according to farmer records. Studied lesions were sole ulcer, dermatitis, interdigital necrobacillosis and hoof abscess, in each case causing lameness. For each hoof-diseased cow, 0 to 3 healthy cows were included, matched with respect to herd, breed, parity and lactation stage. Cell counts were obtained from monthly test recordings from one month before to three months after the hoof-lesion diagnosis, and log-transformed. In total, 203 cell-count observations from 14 hoof-diseased and 32 healthy cows were analysed using mixed least-squares multivariable regression modelling. A random effect for cow identity was included. The principal explanatory variable was disease month, coded as -1 the month before diagnosis, as 0 for the same month as diagnosis, as 1 or 2 for the corresponding number of months after diagnosis, and as 3 for 3 months after diagnosis and all observations in healthy cows. Predictors representing herd identity, breed, parity, lactation stage, milk yield, type of hoof lesion and season were tested but excluded in the final analysis because they were judged not to improve the model. Cows with an acute hoof lesion had a 2.1 times higher cell count the month before the diagnosis (P=0.002) and a 2.3 times higher cell count the same month as the diagnosis (P=0.005) compared to 3 months after the diagnosis and healthy cows.