Hematologic abnormalities over 5 days in cows with acute Escherichia coli mastitis

Abstract

Haematological data from 45 adult Holstein cows with coliform mastitis and systemic clinical signs were studied retrospectively. They developed panleukopenia that resolved over several days, first through an increase in immature forms and later by an increase in mature neutrophils. Neutropenia lasted 3 days in most cows. The majority of cows in early lactation did not develop neutropenia for an unknown reason. Cows with fatal disease could not be distinguished based on haematological analysis, because most died early in the disease, while both surviving and non-surviving cows still had panleukopenia. Cows with coliform bacteraemia had prolonged neutropenia and higher metamyelocyte and myelocyte counts during the regenerative phase. These findings suggest that haematological analysis during the regenerative phase may be useful to identify cows with bacteraemia for more aggressive treatment.