Coliforms

The coliform bacteria which often cause mastitis include Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca and Enterobacter aerogenes.  Coliform infection rates are about four times greater during the dry period than during lactation.  The rate is significantly higher during the first two weeks of the dry period as well as the two weeks before calving. The infection rate is highest in the early stage of lactation and decreases as lactation advances.  Infection rates increase with each succeeding lactation.  Accurate records of new clinical cases, together with milk cultures from clinically infected quarters, help assess the extent of coliform mastitis.  Unfortunately, this impact is not as easy to measure with bulk tank somatic cell counts, individual cow somatic cell counts, whole-herd cultures, culture of a subpopulation of cows or bulk tank cultures.