Comparison of a time series analysis of bulk tank somatic cell counts of dairy herds located in Brazil and the United States.

Abstract: Bulk tank somatic cell counts (BTSCC) is widely used to monitoring the mammary gland health at the herd and regional level. A time series of BTSCC from specific regions or countries can be used to compare the mammary gland health according to regions and estimate the trend of subclinical mastitis of dairy herds at the regional level. This data support economic decisions related to mastitis control at the regional herd level. Still, decisions at the regional or country level are mainly used to investigate the efficiency of the mastitis control program. Three time series of BTSCC from dairy herds located in the USA and the southeastern region of Brazil were evaluated from 1995 to 2014. The first and second USA time series presented an increasing and decreasing trend for the annual geometric mean of BTSCC and the percentage of dairy herds with BTSCC greater than 400,000 cells/mL, respectively. The Brazil time series showed no decreasing trend for the annual geometric mean of BTSCC or for the percentage of dairy herds with a BTSCC greater than 400,000 cells/mL; consequently, approximately 40 to 50% of the dairy herds from southeastern Brazil will not achieve the regulatory limits for BTSCC of 400,000 cells/m Lover the next several years