Relationship between udder and leg hygiene scores and subclinical mastitis.

The objective of this study was to determine the relationship between udder and leg hygiene scores of lactating dairy cattle and measures of subclinical mastitis. Study animals (n = 1250) consisted of lactating dairy cows from eight commercial dairy farms. Herds were enrolled during December 2000 and January 2001 and were visited bimonthly for a total of five visits per herd. Udder and leg hygiene scores were recorded by one person using a four-point scale ranging from one (very clean) to four (very dirty). Udder and leg hygiene scores were compared to bacteriological cultures of milk samples and monthly individual SCC values. Mean hygiene scores were 2.09 and 2.33 for udders and legs, respectively. Udder hygiene scores (UHS) were significantly associated with leg hygiene scores and varied among farms. Linear somatic cell scores increased as udder hygiene score increased. Significant differences in somatic cell scores were observed for all contrasts of udder hygiene score, except between scores of 1 and 2 and of 3 and 4. Linear somatic cell scores were associated with leg hygiene scores, but the only significant contrast was between leg hygiene scores of 2 and 4. There was a significant association between the prevalence of intramammary contagious pathogens and udder hygiene score. The prevalence of intramammary environmental pathogens was significantly associated with udder hygiene score and was 7.7, 10.0, 10.6, and 13.5% for UHS of 1, 2, 3, and 4, respectively. The prevalence of environmental pathogens was not associated with LHS. Cows with udder hygiene scores of 3 and 4 were 1.5 times more likely to have major pathogens isolated from milk samples compared with cows with hygiene scores of 1 and 2.