Approved and unapproved drug use in dairy cattle

Abstract

Criteria used in selecting drugs to be used in treating a lactating cow (diagnosis of disease and causative agent, chemistry and pharmacokinetics of the drug, withdrawal times and economics), antibiotics used by veterinarians either in accordance with label directions or in a dose or manner not indicated on the label, and the use of antibiotics not approved for treatment of lactating cows are discussed. Reasons for using unapproved drugs or approved drugs in unapproved ways are presented. Selection of withholding times for unapproved drugs is also examined.