PREVALENCE OF CONTAGIOUS MASTITIS PATHOGENS IN BULK TANK MILK FROM PRINCE EDWARD ISLAND DAIRY FARMS

摘要

The use of bulk tank milk can be of great value in the control of clinical and subclinical mastitis and potential milk quality problems on a dairy farm. Staphylococcus aureus, Streptococcus agalactiae and Mycoplasma spp. reside primarily in the cow'sudder and therefore, when found in bulk milk, these mastitis causing organisms are strong indicators of the presence of intramamniary infections in the herd. Isolation of contagious pathogens in the bulk milk has been associated with high bulk milk somatic cell count (BMSCC). Only a few studies have determined the prevalence of contagious mastitis pathogens in bulk milk in Canada. Strep, agalactiae prevalence was estimated in Quebec and Alberta in the early nineties at 43% and 6%, respectively. In 1998,58 out of 59 farms from Ontario were Staph. aureus-positivQ~3 either from individual cow samples or from bulk milk samples. On Prince Edward Island Keefe et al. studied herd level prevalence of Staph. aureus and Strep, agalactiae and they found 14% and70% herd level prevalence of Strep, agalactiae and Staph. aureus, respectively. Only one Canadian study reported in Ontario Mycoplasma spp. in bulk milk and individual cow milk, but this study was done in 1972.