The occurrence and treatment of mastitis in U.S. dairy herds is reported to cost as much as $2 billion annually, and part of the challenge in managing mastitis is the difficulty in diagnosing those cows with subclinical mastitis, reported B.W. Woodward of NextGen, A.J. Seykora of the University of Minnesota and T. Koopman of Isogen Animal Care in abstract LB7 presented during the late-breaking research session at JAM 2013 in Indianapolis, Ind.
oodward et al. explained that this difficulty stems from the lack of availability, speed, cost and/or adoption of equipment to individually measure somatic cell count (SCC) for cows at the time of milking, especially during the transition period when the incidence of mastitis is at its highest.
They introduced a new inline device (Mastiline) that provides SCC values by sampling milk from each individual cow directly from the milk flow before it reaches the main milk line. Approximately 120 microliters of milk is drawn into the device where proven ATP measurement technology is used to measure the number of live somatic cells in less than 2.5 minutes.
According to Woodward et al., considerable research over the last 20 years supports ATP measurement as a reliable indicator of SCC in milk. Inside the device, the milk sample is mixed with a specially designed nontoxic reagent that breaks open the somatic cells to release ATP, which is then measured and the results converted into SCC.
Initial laboratory testing of the inline device involved spiking full-fat samples taken from retail pasteurized milk with 50,000, 200,000, and 500,000 cells/mL, as well as raw milk samples from individual cows, Woodward et al. explained. All samples were measured by the device three or four times.
The coefficient of variation (CV) for SCC was less than 9.32% for each retail and raw milk sample repeatedly measured by the inline device, the researchers said, and the CV for retail and raw milk samples with SCC between 100,000 and 500,000 cells/mL was less than 4.30%.