Variation in Daily Shedding Pattern of Staphylococcus aureus in Naturally Occurring Intramammary Infections

Abstract

The cost of mastitis has been calculated at 6% of the value of production; at 2007 prices that is upwards of 2.1 billion dollars. It is estimated that 70-80% of this loss is due to subclinical intramammary infections (IMI) caused by organisms such as Staphylococcus aureus (SA). The control of SA is contingent on accurate diagnosis of IMI, yet currently there exists no standard for the diagnosis of SA IMI. As a result, comparisons between published works are difficult. In addition, the shedding of SA from infected quarters has been described as "intermittent", resulting in recommendations for the diagnosis of SAIMI that are cumbersome and cost-prohibitive in veterinary practice and field research. The goal of this study was to describe shedding patterns of naturally occurring SA IMI over an extended period of time and to provide a reasonable foundation upon which to determine appropriate diagnostic criteria for SAIMI. The effect of PFGE pulsotype on shedding was also examined.