Use of bulk tank and milk filter cultures in screening for streptococcus-agalactiae and coagulase-positive staphylococci

The use of a single bulk tank milk culture and a single milk filter culture was studied for their suitability as screening tests for coagulase-positive staphylococci and Streptococcus agalactiae. Bulk tank and bulk tank milk filter cultures were compared to quarter milk cultures taken from individual cows at 49 Ohio dairy herds selected from all Ohio dairy herds by a stratified random sampling scheme. Individual cow quarter milk samples were collected from a sample of all milking cows using a sampling scheme designed to detect an organism present in 2% of quarters, with 95% confidence intervals between 1 and 3%. Seventeen (35%) herds had one or more cows positive for S. agalactiae and 34 (69%) had one or more cows positive for coagulase-positive staphylococci. Using the results of individual cow sampling as the standard, the sensitivity for S. agalactiae was estimated as 23.5% for a single milk filter sample and 35.3% for a single bulk tank milk sample. The sensitivity for coagulase-positive staphylococci was estimated as 52.9% for a single milk filter culture and 41.2% for a single bulk tank milk culture. Based on these results and those of others, it appears that a single bulk tank or milk filter sample has a relatively low sensitivity for both coagulase-positive staphylococci and S. agalactiae, making these poor screening tests for the presence of these pathogens within a dairy herd.PT: J; CR: 1987, LAB FIELD HDB BOVINE BARTLETT PL, IN PRESS VET PREV ME BROOKS BW, 1982, CAN VET J, V23, P156 GODKIN MA, 1990, SEP INT S MAST IND, P368 GONZALEZ RN, 1986, J AM VET MED ASSOC, V189, P442 GUSTAPHSON TL, EPISTAT STATISTICAL HOGAN JS, 1986, J FOOD PROTECT, V49, P990 KIRKBRIDE CA, 1972, J MILK FOOD TECHNOL, V35, P629 KRAMER RJ, 1980, VET B, V50, P948 MCEWEN SA, 1988, CAN J VET RES, V50, P18 OZ JH, 1985, DAIRY FOOD SANIT, V5, P248 PEARSON JKL, 1976, BR VET J, V132, P588 POSTLE DS, 1968, AM J VET RES, V29, P669 ROBERTSON JR, SEP INT S MAST IND, P112 SEARS PM, 1982, 3RD P INT S VET EP E, V670 SMITH A, 1978, S AFR J DAIRY TECHNO, V10, P131 WARREN HB, 1967, J MILK FOOD TECHNOL, V30, P363; NR: 17; TC: 11; J9: J FOOD PROTECT; PG: 4; GA: GQ448Source type: Electronic(1