Clinical forum: the role of dry cow therapy in the modern dairy herd

Abstract

Antibiotic dry cow therapy (ADCT) is a crucial component for the control of contagious mastitis pathogens as part of a herd's mastitis control policy and recent research has again highlighted the excellent cure rates achieved with ADCT, despite ‘apparent’ cure rates across the dry period averaging much lower than those published. However, following the control of the classic contagious mastitis pathogens, environmental pathogens such as Escherichia coli and Streptococcus uberis have become significantly more important and have resulted in a shift in emphasis at drying off, away from identifying those cows with a persistent infection towards protecting those without. This means there are two clear roles for any dry cow therapy, i.e. the cure of existing infections and the prevention of new ones, giving rise to a challenge for veterinary herd health advisors. This should lead to an increased awareness of the importance of taking an individual cow approach to dry cow therapy — moving away from ‘blanket’ ADCT approaches, using internal teat sealants and products with extended Gram-negative activity to protect against new infections and regularly reviewing the use of ADCT in herds as part of prescribing antimicrobials responsibly.