Algal Poisoning in Livestock and Pets

The myths surrounding algal poisoning

I was thinking that with summer upon us its probably a good time to talk about water quality. Water is the most important nutrient we provide for our animals (and humans; we won’t last long without water). Water gives life to animals and plants, but under certain conditions can be the bearer of some not so wholesome constituents that we should be concerned about (for example vectors of disease like biting midges (Culicoides gnats; no-see-ums, punkies) that transmit bluetongue in livestock, and that carry hemorrhagic disease to deer. We also must start thinking about microscopic organisms that grow in water in less than favorable conditions.

We really don’t know what this summer will bring yet as far as temperatures and moisture conditions, but we do know that over the last several years when conditions have become hot and dry, some of our water sources start to dry up and stagnate, that’s the conditions we must watch for and in those conditions, algae poisoning can become an issue. In other words, cool running water is good and standing stagnant water can be dangerous. Reports over the last several years focusing on toxins in water have been tragic and heartbreaking for us that raise livestock and have pets.

Those of us that have been around a while will recall the term blue-green algae poisoning. Technically cyanobacteria are the culprit and live in a variety of water conditions (freshwater, brackish water, marine environments, and some live in the soil. When these toxin-producing cyanobacteria get prolific, that is termed freshwater harmful algal blooms (FHABs). They can affect the ecosystem and animals in several ways: Oxygen depletion, toxin production (40 known genera of cyanobacteria with the ability to produce toxins), and restricted or unusable water supplies in areas of the world where fresh water is hard to find. The problem with algae blooms has gotten worse with higher water temperatures and eutrophication (i.e., nutrient loading of nitrogen and phosphorus).

The cyanobacteria are microscopic but typically appear as blue-green, red, white, or brown scum on the surface of the water (usually in water > 60°F). They can also appear like spilled paint, pea soup, or striations in the water. In some cases, they may be totally invisible. The problem is that not all cyanobacteria produce toxins and some toxin-producing strains only produce toxins at certain times (seasonal variation). Other cyanobacteria can produce multiple types of toxins.

There are at least eight significant toxins produced by cyanobacteria and cause varying effects on livestock, pets, and humans. Most often the delivery of the toxin from FHABs is ingestion of the cyanobacteria or from ingestion of the toxin itself after the cells of cyanobacteria have broken apart (lysis of the cell).

Symptoms of algal toxins vary by species of animal, the specific toxin(s), and the amount of toxin taken in by the animal. The toxins can be harmful to the skin, liver, kidney, and nervous system. In general, weakness, staggering, paddling, convulsions, breathing difficulty, bloody diarrhea, and death are symptoms to watch for. Onset of signs of poisoning can occur soon after ingestion to 24 hours later. If you suspect poisoning of animals by cyanobacteria, contact your veterinarian immediately for assistance with treatment. Prognosis for animals that have been exposed to cyanotoxins is usually poor.

Prevention of exposure to cyanotoxins is the most effective way to keep animal safe. Producers (including our youth livestock producers) should focus on fresh clean water for their animals: Clean and rinse stock tanks and other water containers regularly; If you use small pools for water-loving dog breeds, these need to be cleaned as well. For livestock on expansive pastures, it is good practice to manage runoff of livestock waste (i.e., buffer strips of perennial plants around water holes) and carefully apply nitrogen and phosphorus fertilizer (if needed for farming or forage operations in proximity to livestock) so these nutrients don’t find there way into livestock water supplies causing algae blooms. Prevent livestock from standing in surface water by providing other water sources and limiting access by fencing. Algaecides have been used but are not selective and they may in fact reduce competition with other algae and therefore increase toxic blooms in the future.

As the weather heats up, a proactive and common-sense approach to water quality will go a long way in keeping our livestock and pets safe. If you suspect a problem with cyanobacteria on your operation, the following is a list of laboratories that can test your water. Contact them directly for sampling and shipping instructions.

Aquatic Services, 42184 Tweedle Lane, Seaside, OR 97138. Phone 503-755-0711. Contact: Wayne W. Carmichael, PhD. (Consulting and lab services, algal identification/enumeration.)

Aquatic Analysts, 126 Ocean View Dr, Friday Harbor, WA 98250. Phone 503-869-5032. Contact: Jim Sweet. (Identification and enumeration only, cheapest.)

King County Environmental Laboratory, 322 W Ewing St, Seattle, WA 98119. Phone 206-684-2300; direct 206-684-2358. Contact: Fran Sweeney. (Identification/enumeration and toxin testing for microcystin.)

Water Management Laboratories, 1515 80th St E, Tacoma, WA 98404. Phone 253-531-3121. Contact: Diane DuMond. (Identification/enumeration and toxin testing.)

Summer is here! Stay safe and have some fun! Please let me know if I can assist you with your cattle, forages, and feed.

— Don Llewellyn is the WSU Lincoln County Extension Director in Davenport. He can be emailed at don.llewellyn@wsu.edu