Risk of New Intramammary Infections during the Dry Period in Holstein Dairy Cattle Enrolled in the CBMRN National Cohort of Dairy Farms

Abstract

Intramammary infections acquired during the dry period are difficult to diagnosis and tend to lead to decreased production in the subsequent lactation. In addition, the use of dry cow therapies (DCT) have virtually eliminated major pathogens, such as Streptococcus agalactiae. However, use of dry cow therapy or teat sealants may have questionable efficacy against other pathogens. Selective dry cow therapy, based on farm- or cow-specific pathogen profiles, tend to decrease usage of antimicrobial products. However, to generate farm-specific pathogen profiles, knowledge of incidence of intramammary pathogens is needed.
 The objectives of this observational study were to determine the incidence of new intramammary infections (NIMI) in dairy cattle during the dry period and risk factors associated with NIMI incidence risk.