A new study
reported in the January issue of the Journal of Dairy Science today reaffirms the notion that low somatic cell counts and mastitis prevention are key to reducing new clinical cases after calving.
The study involved 218 cows from the University of Wisconsin herd. In the first 120 days after calving, clinical mastitis was found in 47 of the cows.
Researchers found that quarters that had at least one case of mastitis during the previous lactation were 4.2 times more likely to have mastitis in the subsequent lactation compared to mastitis-free quarters. And quarters with cell counts greater than 200,000 at dry off and postcalving were 2.7 times more likely to have mastitis than quarters with cell counts below 200,000.
Older cows are also more susceptible to mastitis. Cows having their fifth or later calf are 4.2 times more likely to have mastitis than cows in their second lactation.
The study found that gram-negative pathogens (typically thought of as environmental forms of mastitis rather than infectious) were the most common pathogens associated with the clinical cases.