繁殖用黒毛和種牛の蹄における白線離開病変の発生状況

Abstract

To clarify the etiology of white-line disease in Japanese Black (JB) cattle, the prevalence of white-line separation was investigated in 156 hooves (from 39 JB cattle) obtained from a slaughterhouse. Multiple Logistic Regression Analysis was used to extract factors that could affect the occurrence of white-line separation. Explanatory variables were age, body weight, and hoof configurations (toe length, toe angle, wall concavity, and wall ridges). Prevalence of white-line separation was shown to have no significance in the cases of the lateral and medial hooves of the fore and hind feet. The odds ratio of white-line-separation occurrence in JB cattle with toe lengths of >85mm was 6.51 (1.97-21.52/95% confidence limits) times those of toe lengths of ≤85mm. These results indicate that in JB cattle, white-line separation is related to weakness of the white line at ground surface caused by increased toe length.