Corynebacterium pyogenes mastitis among heifer calves

In August 1975 an outbreak of C pyogenes mastitis occurred involving 18 heifer calves at the National Institute for Research in Dairying. This paper describes the outbreak which affected animals varying in age from five to 22 months. Fourteen of the cases (77%) were among calves less than 10 months old. The advisability of using fly control measures among young stock in the summer months is discussed.