Pasture pond covered with algae

Producer Question from 2012

Q.  Pasture pond is covered with algae. Will it be harmful to the cattle if they drink the water? (July 24, 2012)

A.  Algae have appeared in some farm ponds to be used for livestock source of water this spring and summer. There is not a lot of information on the impact of toxins produced by algae on cattle performance and morbidity or mortality.

The blue-green algae appear to be the concern. The toxin is held within the cell wall of algae. When the algae lyse (fancy word for cell wall rupture) then the toxins and the blue-green pigments are released.

Cells walls can be broken by stomach acid, or naturally by UV light (sun light). If the algae are consumed, an algal cell that contains a toxin, stomach acid can cause the toxin to be released. If the algae in the water contains a toxin and it is exposed to the proper amount of UV light then the cell lysis and the toxin is then released into the water. If the pond looks like pea-green soup or the water looks like John Deere paint, then there is a potential for the water to contain toxins.

Whether these toxins are detrimental to cattle is uncertain. If the blue-green algae was in the pond at some point in time this spring and now is gone, it doesn't mean that the water doesn't contain toxins. The toxins produced by the algae can still remain in the water for two to three weeks post disappearance of the algae.

For additional information, please see the UNL NebGuide Water Requirements for Beef Cattle, G2060 (PDF version 628KB).

Dr. Rick RasbyDr. Rick Rasby, Professor of Animal Science
Animal Science, University of Nebraska - Lincoln, Lincoln, NE