Watch Your Water!

In the summer months, particularly during periods of hot weather we occasionally diagnose cases of blue-green algae (cyanobacterial) toxicity.  In previous years our diagnoses have been in cattle, although other species can be affected.   

This condition should be considered in cases of otherwise undiagnosed sudden death, particularly in cattle at grass depending on their water supply. In the acute stages of the disease process cattle can show nervous signs and muscle tremors. In the chronic form of the disease cows show a toxic hepatopathy and potentially a secondary photosensitisation.  This is the form we diagnose more commonly based on liver histopathology. 

High water temperature, shallow water and high concentrations of nitrogen in the water pre-dispose to algal blooms.  Animals drinking near the edge of a pond are more predisposed as the algae and toxins are concentrated in the superficial layers.  Another risk factor might be water troughs in fields that have been shut up for silage that then return to grazing where water troughs might need cleaning and water refreshed. 

Depending on how the rest of the summer’s weather goes the risks of this condition occurring might be higher. It is a good prompt for farmers to ensure that water troughs are cleaned out. There are regulations on how and where livestock should have access to water courses from an environmental perspective and if there are concerns about algal blooms, livestock should be fenced off affected natural water supplies.