We have long believed our goats spend hours searching for new and unusual ways to kill themselves. The most recent – and unique – method they found at our farm was to ingest toxic blue-green algae.

The scientific name for blue-green algae is cyanobacteria. Cyanobacteria are normally unicellular and manufacture their own food, relying on sunlight for photosynthesis.

Most aquatic ecosystems (creeks, rivers, lakes, etc.) contain blue-green algae that may or may not be visible to the human eye. But when conditions are right, the numbers can rapidly increase; and “blooms” (also called scum) can be seen on water surface. These algal blooms can be toxic to animals.

British researchers claim the blooms are more prevalent in late summer and early fall when warm weather is followed by heavy rainfall then more warm conditions. Blooms will normally disappear in winter. Canadian researchers report the blooms appear in the hot summer months and are more prevalent in the prairies.

Thomas Morris, MD, Medical Epidemiologist in North Carolina wrote, “Cyanobacteria also have lipopolysaccharides (LPS, similar to compounds found in the cell walls of Gram-negative bacteria such as Escherichia coli) which are potent mediators in the mammalian immune system. Mortality from cyanobacteria is mostly confined to veterinary reports in pets and livestock that have drunk water densely packed with algae.”

There are between 10 (according to British research) and 50 (according to Dr. Morris) genera of blue-green algae that are toxic with the most common being Microcystis, Anabaena, Aphanizomenon, and Oscillatoria. The three main toxins are endotoxins, neurotoxins, and hepatotoxins. Endotoxins are primarily irritants which produce allergic reactions, rashes, and sometimes gastroenteritis. Neurotoxins cause muscle tremors and nerve damage while hepatotoxins damage the liver.

In general, the blooms do not have a long life, usually disappearing within days. The blooms are associated with eutrophication, the process of nutrient enrichment by phosphates and nitrogen. In rare occasions when conditions remain favorable, the blooms can remain for months if nutrient levels are high. When cyanobacterial toxins are discovered in a water system, they can be removed by using activated charcoal, but chemicals such as copper sulphate should not be used.

Per to Dr. Thomas, “Not all cyanobacteria produce toxins, and even those known to produce toxins are not always producing the compounds shown to be toxic.”

These toxins may be colorless, odorless, and remain in the water for weeks after the blue-green algae disappears. These toxins are not destroyed by boiling the water.

According to the Cooperative Research Centre for Water Quality and Treatment in Australia, “The first documented case of an algal bloom causing deaths occurred in South Australia’s Lake Alexandrina in 1878. In that case, cattle, pigs and sheep died within hours of drinking contaminated water.” Since 1878 there have been many other documented incidents of poisoning – both of wild and domesticated animals. According to Health Canada, “Animals are not more sensitive than people to the effects of the toxins; they are simply not as concerned with the way water looks or smells before they drink it.”

Also according to Health Canada, “Death is usually caused by damage to the liver or to the nervous system, depending on which toxins were predominant in the water. Treatments to counteract the effects of cyanobacterial toxins in animals have not been extensively investigated to date.”

When we recently lost the four goats and had seven additional goats down due to what we now believe was blue-green algae, we are convinced the seven goats we saved recovered because we gave them penicillin orally to kill the bacteria in their rumen. The area we think was infected contained runoff water from the hillside where the goats spend their evenings (and where they spill feed and release urine and nannie berries). Heavy rains caused the runoff water to settle in a small depression just inside the hay field. Weather conditions and flooding prevented the area from drying and contributed to the formation of the blue-green algae blooms.

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Ken and Pat Motes
Clear Creek Farms
33 South Clear Creek Road
Fall River, Tennessee 38468
Phone: (931) 852-2167
Fax: (931) 852-2168

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