EVALUATION OF FIXED FACTORS AFFECTING HOOF HEALTH

Hoof trimming data were collected from the University of Illinois dair y farm. Normality transformed scores for six traits (corkscrew claw (C C), heel erosion (HE), interdigital dermatitis (ID), laminitis (LA), s ole ulcers (SU) and white line separation (WLS)) were tested for fixed factors (breed, year, season, age, trimming interval and months postp artum) by an animal model. Ayrshires and Jerseys had 'better' claw sco res for all six traits. Brown Swiss had the worst score for CC. LA, SU and WLS were worst in Guernseys, and HE and ID were worst in Holstein s. November was the highest risk season for HE, SU and LA, whereas WLS was worst at July trimming. Scores of CC and ID were worst in March. Risk of each of the six traits increased with age. A 4-month trimming interval had worse scores than a longer trimming interval for all trai ts except SU and CC. This emphasized that cows trimmed more frequently usually had a higher probability of repeating their problems. Multipl e environmental factors were significantly involved in the expression of one or more of the six hoof traits.