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Published on: July 3, 2014
Clinico-pathological findings in cattle exposed to chronic bracken fern toxicity
M D Perez-Alenza1, J Blanco, D Sardon
1Department Animal Medicine, Surgery and Pathology, Veterinary Medicine School, Complutense University of Madrid, Ciudad Universitaria, 28040 Madrid, Spain.
Aim:
To describe changes in blood and urine analytes in a large group of cattle exposed to chronic bracken fern toxicity, in order to identify parameters of potential diagnostic value.
Methods:
The study was conducted on two livestock farms on which bovine enzootic haematuria (BEH) was known to occur; Farm A grazed a local breed of cows and Farm B grazed Friesians. Group A1 comprised 66 cows from Farm A, Group B 54 cows from Farm B, and Group A2 13 heifers from Farm A. Ten healthy cows were used as controls. A complete physical examination was performed (Group A1), and blood (all groups) and urine (Groups A1 and B) samples were collected. Necropsies and histopathology were undertaken on four cows.
Results:
Anaemia, leucopenia, monocytosis, thrombocytopenia, hypergammaglobulinaemia, microhaematuria and proteinuria were detected. Multivariate statistical analyses established three phases of the disease of increasing severity; an initial phase, characterised by an extremely high monocytosis and otherwise normal parameters; an intermediate phase, characterised by monocytosis and moderate changes to other analytes; and a final phase, characterised by normal levels of monocytes and many changes to other analytes.
Conclusions And Clinical Relevance:
Monocytosis, detected in 31% of the younger animals, could represent an initial response to consumption of bracken fern and might be useful as an early haematological marker of BEH.
