Factors associated with the occurrence of severe teat-end hyperkeratosis in dairy herds in southern Brazil.

Abstract

We aimed to evaluate animal- and farm-level factors associated with severe teat-end hyperkeratosis (THK) in dairy herds in southern Brazil. The study was conducted in 11 farms and included 642 lactating cows. Farms were visited four times over a year to collect data on THK scores. Cows were classified as having severe THK if at least one teat was scored as 4. Parity, days in milk (DIM), milk yield, and somatic cell count (SCC) data were obtained monthly from official milk recording systems. Frequency analysis were performed to evaluate the occurrence of severe THK within different classes of milk yield, parity, DIM, and SCC, and variables related to milking system and maintenance. Logistic regression was performed to estimate risk factors associated with severe THK. Cows producing <20&#xa0;kg/day had lower odds of severe THK than cows producing 20-30&#xa0;kg/day (OR: 0.56; 95% CI: 0.33-0.94) and&#xa0;>&#xa0;30&#xa0;kg/day (OR: 0.44; 95% CI: 0.25-0.78). Early-lactation cows were less likely to develop severe THK than cows with 101-200 DIM (OR: 0.64; 95% CI: 0.41-0.99) or 201-500 DIM (OR: 0.59; 95% CI: 0.37-0.94). Primiparous cows had lower odds of severe THK than multiparous cows (OR range: 0.50-0.58). Farms without automatic cluster removers, those milking cows three times per day, and those performing sporadic maintenance of the milking system showed a significantly increased risk of severe THK. These findings highlight the importance of appropriate milking management and equipment maintenance to mitigate severe THK.