Relationship of early first lactation somatic cell count with risk of subsequent first clinical mastitis

摘要: Abstract The relationship between initial Somatic Cell Count (SCC) and time to first clinical mastitis was estimated from data including 20,422 Holstein heifers, without signs of during the month lactation with a test day SCC lower than 400,000 cells/ml. Number days 35 after calving event in or second studied using survival analysis methodology, allowing for censored data. model included effects milk yield at test, herd-year, month, stage. Separate analyses were also performed subsets herds low high frequency SCC. risk highest around calving, lactations starting summer, high-yielding cows. probability occurring increased continuously as increased. same pattern observed level. In lowest frequencies, occurrence weakest. But all situations, results indicated that cows had mastitis, any intermediate optimum.