OBJECTIVE: To determine herd-level prevalence of Mycoplasma spp mastitis in Utah dairy herds and characterize farms and management practices for positive herds. DESIGN: Epidemiologic study. SAMPLE POPULATION: Bulk tank milk samples from 222 of 285 (78%) dairy farms in Utah. PROCEDURES: Milk haulers or dairy producers collected 5 milk samples from all bulk tanks at 3- to 4-day intervals for mycoplasmal culture. Owners of all positive herds were offered follow-up visits. RESULTS: Milk samples from 16 of 222 (7%) herds had positive mycoplasmal culture results. Follow-up information was obtained from 14 of 16 herds; 12 provided complete data. Some characteristics of mycoplasma-positive herds included the following: 8 of 14 herds had > 750 lactating cows, 9 of 11 had bulk tank milk somatic cell count of 140,000 to 240,000 cells/mL, 7 of 11 had actual milk production of 9,535 to 11,622 kg (21,000 to 25,600 lb)/305 d, 11 of 12 had cows with clinical mastitis that was nonresponsive to treatment and involved >or= 2 mammary gland quarters, 9 of 12 had cows with clinical mastitis that spread from 1 mammary gland quarter to another, 8 of 12 had cows with droopy ears, 7 of 12 had cows with a head tilt, 7 of 12 used common milking towels, 2 of 12 were closed to replacement cattle for > 1 year, and 2 of 12 purchased bulls only. CONCLUSIONS AND CLINICAL RELEVANCE: Herd-level prevalence of mycoplasma mastitis in Utah was relatively high, compared with other areas of the United States.
OBJECTIVE: To determine herd-level prevalence of Mycoplasma spp mastitis in Utah dairy herds and characterize farms and management practices for positive herds. DESIGN: Epidemiologic study. SAMPLE POPULATION: Bulk tank milk samples from 222 of 285 (78%) dairy farms in Utah. PROCEDURES: Milk haulers or dairy producers collected 5 milk samples from all bulk tanks at 3- to 4-day intervals for mycoplasmal culture. Owners of all positive herds were offered follow-up visits. RESULTS: Milk samples from 16 of 222 (7%) herds had positive mycoplasmal culture results. Follow-up information was obtained from 14 of 16 herds; 12 provided complete data. Some characteristics of mycoplasma-positive herds included the following: 8 of 14 herds had > 750 lactating cows, 9 of 11 had bulk tank milk somatic cell count of 140,000 to 240,000 cells/mL, 7 of 11 had actual milk production of 9,535 to 11,622 kg (21,000 to 25,600 lb)/305 d, 11 of 12 had cows with clinical mastitis that was nonresponsive to treatment and involved >or= 2 mammary gland quarters, 9 of 12 had cows with clinical mastitis that spread from 1 mammary gland quarter to another, 8 of 12 had cows with droopy ears, 7 of 12 had cows with a head tilt, 7 of 12 used common milking towels, 2 of 12 were closed to replacement cattle for > 1 year, and 2 of 12 purchased bulls only. CONCLUSIONS AND CLINICAL RELEVANCE: Herd-level prevalence of mycoplasma mastitis in Utah was relatively high, compared with other areas of the United States.