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Water Quality

Blue-green algae is a problem worldwide and can occur almost anywhere with fresh, open water and the right combination of nutrients and sunlight.

“It’s a really challenging problem because, as human beings multiply, we are obliged to provide food,” noted Deon van der Merwe, toxicology section head and associate professor at Kansas State University.

“Arguably, the largest source of nutrients that eventually make their way into lakes and cause the trigger of blooms is nutrients from crop production,” he continued.

Blooms of algae

Algal blooms are composed of normal organisms that are part of the natural ecology of lakes and other water bodies.

“In many ecosystems, those organisms – called cyanobacteria – are very important primary producers. They produce the initial food for other organisms to build on, and we eventually have fish,” he explained. “The whole production of the animal ecosystem is dependent on these organisms being there.”

Cyanobacteria become a problem if conditions promote an overgrowth of the algae. Too many nutrients, coupled with intense sunlight, may lead to hazardous blooms.

“Conditions in the summer, for example with a heat wave and many cloudless, hot days, tend to promote the growth of the organisms,” he says.

Increased incidences

One of the reasons algae blooms have become more common, according to van der Merwe, is that the landscape is changing. Many years ago, there were fewer open bodies of water.

“We create small water bodies, such as ponds for livestock and lakes for recreation and water management. This creates opportunities for the organisms to cause a problem when the conditions are right,” he comments.

Often, when there is an economic impact, it is not directly related to livestock or human poisoning. Costs are more commonly incurred when risk mitigation efforts are implemented to prevent poisoning events.

“When we have risky conditions, and we have to take action, we have to close lakes, farmers have to provide alternative water sources for livestock, etc. It really is a wide economic footprint if we think about conditions that lead to risk,” he noted.

Hazardous toxins

There are various species of cyanobacteria that cause alga blooms and a variety of  risks associated with them. One of the most common types of toxins created by cyanobacteria is called microcystin.

When van der Merwe first began looking into alga blooms, there was a particularly severe case of mycrocystin in a pond that dogs had access to.

“When the dogs visited the lake and ingested the material, they would typically die within a couple of days of ingestion from a very serious, rapidly developing disease due to liver failure,” he explained.

At first, the toxin causes a rapid inflammatory response, but if it is ingested, it will cause vomiting and diarrhea, leading to liver failure and death if the dose is high enough.


“Liver toxins are very important, but probably the second most important toxins, looking at the impact and number of cases we see, are some of the neurotoxic substances that are produced by cyanobacteria,” continued van der Merwe.

Anatoxin-a and anitoxin-as are two common neurotoxins that can be produced in algal blooms.

“These are quite similar in effect, but they are different toxins,” he explained. “They affect the muscular-skeletal system, and the control of the muscle becomes abnormal.”

Initially, muscle spasms or convulsions will be observed, and if the condition persists, paralysis or death can follow.

“It acts very fast. Anatoxin-a’s original name was ‘Very Fast Death Factor’ because when they injected mice with an extract of this algal scum, the mice would die very fast. Later on, when they described the structure and figured out more exactly what it was, they called it anatoxin-a,” he commented.

Impacted species

Toxins from algal blooms can affect any number of species, from livestock and pets to people, wildlife and even fish.

“If fish are swimming in a lake where there are high concentrations of the toxins and they are not able to avoid those high concentrations, fish might actually die,” noted van der Merwe.

The main factor impacting how different species are affected by the toxins is generally related to their exposure or how much of the toxin they ingest.

If a case of hazardous algal bloom occurs in a body of water, the first sign is typically a change in water color. In many cases, the change will be toward green, but it can be brownish or reddish, as well.

“It’s variable. Just a change in color is a danger sign,” stated van der Merwe.

Another sign is a collection of scum or an accumulation of blue, green, brown or red material along the downwind edges of a pond.

“It can be that the algal bloom will form a scum that floats on the surface, which is quite common but not always the case. Because they float to the surface, if there is a breeze that blows across the pond, they tend to blow along the water surface,” he remarked.

Taking action

If a hazardous bloom is suspected, van der Merwe recommended preventing access to the water.

“What we can do about the problem depends on the type of pond and the circumstances,” he added.

In some cases, chemicals can be used to break up the algae, although they may only be effective for killing the current cyanobacteria. If conditions in the water remain the same, a new bloom can form.

“Things like copper can effectively kill the organisms. If we have a serious bloom, that is an option if the conditions are right,” he suggested.

Preventing light from reaching the water is also a recommended remedy. Adding trees for shade or adding specific products to the water that shade penetrable light are also potential solutions.

“If we have a lot of water plants in and around the water, they compete for nutrients with the cyanobacteria, so that can reduce the incidence as well. There are a lot of different things that can be used to prevent the problem from reoccurring,” said van der Merwe.

Natasha Wheeler is editor of the Wyoming Livestock Roundup and can be contacted at This email address is being protected from spambots. You need JavaScript enabled to view it..

“Water is the most undervalued and forgotten about nutrient when it comes to livestock,” said Saskatchewan Ministry of Agriculture Livestock Specialist Leah Clark. 

Clark was featured in a Canadian Beef Cattle Research Council webinar titled “What’s in your water? Water quality and the economics of pump systems.”

Importance of water

“Water is the most important essential nutrient for the biological function of animals,” Clark said. “Water intake and quality will affect feed intake, absorption of other nutrients, general health, weight gain, milk production and productivity.”

Clark noted limiting the availability of water to cattle will depress production rapidly and severely because there is a direct relation between feed and water intake. 

“Poor quality drinking water is often a limiting factor of feed intake and ultimately weight gains,” according to Clark. “There are a lot of factors that can affect the safety and palpability of water.” 

Clark lists some of the factors affecting production as hardness, alkalinity, total dissolved solids (TDS), conductivity, nitrates, sulfates, iron, algae and sodium, among others.  

“If we just look at the sheer volume of water in cattle, mature cows are 75 percent water, and calves are 80 percent water,” said Clark. “The range of water needs is determined by lactation and heat.”

Total dissolved solids 

TDS is a sum inorganic salts dissolved in the water, according to Clark. 

“The most abundant of these solids are sodium, calcium, chloride, magnesium, sulfates, nitrates and iron,” said Clark. “There are others but these are the most often seen in livestock scenarios.” 

“The tolerance level for livestock depends on the species,” she said. “Beef cattle have a max tolerance up to 5,000 milligrams per liter.” 

She noted cattle exposed to too much TDS will experience diarrhea and overall decreased gains.  

Total dissolved solids can be tested for using lab analysis or hand-held meters, according to Clark. The handheld meters don’t actually measure TDS. They measure conductivity and use a conversion method. 

“It’s important to understand these handheld meters can be a good screening tool if accurate,” she continued. “Lab tests are still the gold standard when it comes to accuracy.” 

“When test methods were compared, it was found the handheld meter readings did not show as much TDS as the lab test of the same water,” Clark explained. “We also found the previously held belief of a 64 percent conversion of conductivity was wrong and 97 percent was more accurate.”


Clark explained intake of sulfates in excess can also wreak havoc on the health of beef cattle. 

“Excessive sulfate intake may cause direct toxicity,” she said. “But the detrimental effects are associated with metabolic interference.” 

She noted sulfur will also interact with trace minerals in the animal. These interactions can lead to a deficiency in certain necessary trace minerals. 

“Excessive sulfur impairs thiamine synthesis,” Clark explained. “This particular impairment can lead to polio in cattle.”

The National Academies of Sciences, Engineering and Medicine recommend beef cattle have a suitable ration of 0.15 percent sulfate in their total diet. Max levels shouldn’t exceed 0.5 percent, according to Clark. 

“What we have to remember about these recommendations is they are encompassing the entire diet, not just water intake,” Clark noted. “As we start thinking about these things we need to look at both the diet and water of the cattle.”

“Causes of excessive sulfate include diet, rumen environment and mineral status among others,” said Clark 

The implications of high sulfate levels include reduced fertility and weight gain as well as immunity and skin issues, as per Clark. 

“With fertility, cows and heifers can have delayed cycling or skipped cycles,” she said. “Bulls will experience decreased production of sperm.”

She noted weight gain can be affected due to changes in metabolism and decreased feed and water intake. 

Algae and Bacteria 

“In the summer months, we also need to be monitoring bacteria and algae in our cattle’s water supply,” Clark stressed. 

She explained algae can function as an indicator of water quality. It thrives in nutrient-rich, stagnant water. 

“Smelly bacteria can persist in the winter months where there are anaerobic bacteria and nutrients present,” said Clark.

Clark explained cyanobacteria can produce neuro or liver toxins that can be fatal in cattle. She noted cyanobacteria are bacteria and not true algae, contrary to what the appearance suggests. 

“Cyanobacteria is planktonic free floating in the water column,” Clark said. “It has a green to dark brown appearance and looks similar to grass clippings or pea soup.” 

“Neurotoxins are fast acting and cause paralysis of the skeletal and repertory system,” Clark explained. “This type of toxin will kill cattle very quickly and symptoms include scours, mental derangement, muscle tremors and stiffness.” 

“Hepatotoxins can also be fatal but take longer to kill cattle in comparison to neurotoxins,” Clark noted. “These toxins affect the liver.”

Decreasing algae and bacteria

Clark explained issues with algae and other toxins can be magnified in the summer. Due to the heat, cattle demand more water and therefore will consume more. Because of the dry weather, there is no way to recharge sources so poor water only gets worse.

“Identification is key,” Clark said. “Some bacteria and algae look very similar but are treated quite differently.” 

She noted some algae are beneficial so identifying whether or not the algae is harmful or not is very important. 

“There are commercial products available to treat algae and bacteria,” Clark noted. “But proper management can help minimize these issues.” 

“We have the ability to deal with some problems in water quality,” she said. “But doing so requires a commitment of time and resources from producers.”

Callie Hanson is the assistant editor of the Wyoming Livestock Roundup. Send comments on this article to This email address is being protected from spambots. You need JavaScript enabled to view it..

Sheridan – Water quality concerns remain paramount for many across Wyoming, and the Wyoming Association of Conservation Districts (WACD) heard from researchers at the University of California, Davis about research that has looked at the impacts of cattle grazing on microbial loading of waters. 

“We’ve been doing research over the last 20 years on sustaining livestock, water quality, habitat and sensitive species on rangeland watershed in California,” commented Ken Tate, a UC Davis researcher. “Leslie Roche and I represent a group out of California that focuses on rangeland management.”

Tate and Roche presented at the Wyoming Association of Conservation Districts Annual Convention Nov. 18-20 in Sheridan.


California ranchers graze on nearly 57 million acres of rangeland that are divided between public and private ownership. 

“We have about 1 million acres of irrigated forage, and it is essential to our livestock acreage,” Tate said. “These acres are in a very diverse ecosystem with hundreds of vertebrates and thousands of invertebrate and plant species.”

In addition, 85 percent of surface waters in the state are used for municipal purposes. Water reservoirs for San Francisco are surrounded by vast tracts of rangelands, which are used for cattle grazing to control plant species.

Water concerns

In the early 80s, concern was expressed by the environmental community and regulatory agencies about rangeland watershed and clean water, particularly focused on human health. 

“The big water topic that won’t go away for us is microbial water quality as it relates to livestock production,” Tate said. “When I arrived at UC Davis in April 1995, I began testifying at the Public Utilities Commission in San Francisco in the midst of an ongoing debate being held in the news media as to whether or not livestock were the source of a protozoan pathogen called Cryptosporidium parvum.”

The pathogen had shown up in the water source and impacted the human health of San Francisco, making it a large concern. At the same time, testing for the species is difficult and expensive, chlorination doesn’t kill the protozoa, and filtration systems capable of addressing the pathogen are expensive.

“From that event, our group started a 20-year journey of trying to understand as much as we could about the ecology and biology of microbial pollutants,” Tate noted.

Animal production

One aspect of Tate’s research looked at how many microbes are produced in the fecal matter of cattle. 

“When we look at fecal coliforms, we see that fresh, right-out-of-the-cow, 10 million plus colony forming units are present per gram of manure,” he said. “A cow produces about 7 trillion E. coli a day. If we look at indicator E. coli, they put out about 1 million or more per gram of feces.”

Looking at Cryptosporidium parvum, Tate noted that 15 to 20 percent of calves at three to four months of age are infected, and they shed the microbe at a rate of approximately 100 eggs per gram. 

“Less than five percent of the cows in rangelands have C. parvum, and they shed it at a low rate – about one to 100 eggs per gram,” he said. “That is a small population of cows.”

“We were surprised that indicator bacteria are not correlated to the pathogen at the creek, but they aren’t correlated at the end of the cow,” Tate continued. “E. coli is not a good indicator for pathogen contributions from livestock.”

Species concerns

At the same time, new research has also indicated that the species of Cryptosporidium creating human health problems isn’t the same as that present in cattle. 

“With better taxonomic skills and better technology, we went back out and sampled 450 cow/calf pairs,” Tate said. “We found that 14 percent were infected with Cryptosporidium, but zero percent were C. parvum, which was the species we were worried about.”

Though the other species may be minimally infectious to humans, he noted that cattle “might not be the public health threat that we thought. Other scientists still need to follow and confirm this work.”

Pathogen survival

Tate further looked at the survival of pathogens in the environment, noting that the survival of many bacteria is very poor after leaving the host. 

“One of the first best management practices that was voiced when it comes to livestock production and microbial water quality is how far back from water sources do we need to build the fences,” Tate said. “We didn’t know if it needed to be 100 feet or 400 feet.”

A subsequent research project modeled temperature of cattle fecal pats during the day in a variety of conditions. The data was then mimicked in water baths in a laboratory. Known amounts of bacteria were added to the water baths and survival rates were measured. 

“If temperatures hit 104 degrees at some point during the day, it only took one day for 90 percent of C. parvum to die,” Tate noted. “At about 78 degrees ambient temperature, fecal pats reached 104 degrees.”

“We get a lot of 78-degree days in California, so we have a lot of days in the spring, summer and fall where the range is acting as an autoclave,” he continued, noting that the only period of concern is during the winter, when cooler temperatures mean that bacteria would survive longer.


Further, Tate noted that once the microbes leave the host, their ability to move in the environment is limited.

“Based on 40 to 50 storm events in 36 runoff plots, we looked at E. coli, Cryptosporidium and Salmonella,” he said. “If we get 16 storm events over the course of the season, 90 percent or more of the E. coli is still in the fecal pat or within 10 centimeters of it.”

Each meter away from the fecal pat, leaching of bacteria and protozoa is reduced an additional 79 to 99.99 percent.

Management tools

As a result of their findings, Tate said management actions associated are quite simple.

For example, calving in dry areas away from wet corrals and creeks reduces the survival of microbes. 

Additionally, Tate commented that because the microbes don’t move away from the fecal pats readily, keeping cattle out of creeks is often sufficient to reduce loading. Fences around creeks and riparian areas only need to be several meters from the banks.

“High stocking rates can lead to increased livestock water loads because there is more fecal matter out there,” he said. “We also need to avoid reduced infiltration due to compaction.”

As water seeps into the soil, filtration is increased, and the prevalence of microbes is reduced.

“I believe in working landscapes, and livestock are an important part of the landscape,” Tate added. “Not everyone in California agrees with me, though.”

Indicator bacteria

University of California, Davis researcher Ken Tate noted that often, indicator bacteria, such as Escherichia coli, are used to determine if water is safe to drink. 

“The fecal indicator bacteria are things we regulate on and things that we tend to monitor,” he explained. “We hope that monitoring for those bacteria, which is cheap and relatively simple, will indicate the presence of fecal material and potential for pathogen.”

Tate’s team looked at whether or not such a correlation was true for western rangelands. 

After months of research sampling irrigated pastures and meadows, he noted, “We continue to see a lack of relationship between indicator bacteria and pathogens.”

“It is a little disheartening,” Tate commented. “The relationships are a lot stronger in an urban watershed, and if the fecal source is more dominated by humans, the relationship get better.”

However, he noted that they continue to look for a way to detect potential harmful bacteria, commenting, “Maybe it is worth the money to start looking at the actual pathogens we are concerned about.” 


Look for information from Leslie Roche’s presentation at the WACD Annual Convention in an upcoming edition of the Roundup.

Saige Albert is managing editor of the Wyoming Livestock Roundup and can be reached at This email address is being protected from spambots. You need JavaScript enabled to view it..

Casper – Microbial source tracking (MST) has been implemented in several districts across Wyoming in the last couple years, according to Cathy Rosenthal, Wyoming Association of Conservation District (WACD) watershed coordinator.

Rosenthal hosted the MST session during the Progressive Resource Manager Forum at the Wyoming Natural Resources Rendezvous on Nov. 27 in Casper to review the last two years of MST.

“MST is a more specific method of determining microbial sources, like E. coli, compared to other similar methods,” Rosenthal explained.


Crook County Natural Resource Department (CCNRD) District Manager Raesha Sells discussed MST sampling in Crook County from the past two years.

“CCNRD conducts water sampling on the Belle Fourche River and Donkey Creek, where there is a total maximum daily load (TMDL) in place for E. coli, chloride and ammonia,” she said.

The Environment Protection Agency (EPA) requires a TMDL when an impaired water body is not removed from the impaired water body list after eight to 13 years, according to Rosenthal.

CCNRD hasn’t conducted MST sampling since 2015. MST was originally conducted to determine to source of E. coli in the Belle Fourche River and Donkey Creek, explained Sell.

“Eight different markers were tested looking for canine, ruminant and human sources. In 2015, the results showed one human hit, 11 ruminant hits and six canine hits,” she noted, adding CCNRD correlated data with Campbell County Conservation District for the canine and human results.

According to Sells, MST has been difficult for CCNRD to use for ruminants because the markers are not specific to cattle, sheep or wildlife.

“Due to the broad scope of MST markers, CCNRD discontinued MST sampling until more specific markers could be developed,” stated Sells, adding best management practices with landowners are being used to reduce E. coli within the watershed.

Tiered approach

Both Campbell County Conservation District (CCCD) and Popo Agie Conservation District (PACD) implemented MST tiered approaches.

“In 2006, CCCD spent grant funding to fix septic systems, but E. coli was still a problem, so we started using the MST tiered approach to find the human source,” stated Jay Quintanilla, CCCD water and range technician.

For two years, CCCD MST sampled the Little Powder River for human E. coli sources, resulting in zero human hits. CCCD decided to implement best management practices in that area to direct funds into a more cost effective project, according to Quintanilla.

“MST is a valuable tool that gives us some confidence to tell stakeholders there isn’t a major problem,” he added.

In 2017, Quintanilla stated CCCD moved up the tiered approach by investigating avian E. coli sources because there were a lot birds at all of the MST testing sites.

“We were only able to obtain five days of sampling for avian sources, so we will continue with the avian approach in 2018,” he stated.

In PACD, E. coli has been monitored since 2002, and best management practices were implemented to help reduce the concentration.

“We realized that to implement targeted best management practices, the E. coli source needed to be located,” stated Dave Morneau, PACD conservation technician.

He said PACD was directed to look more at human sources in 2006 and some key projects were implemented, but the data was inconclusive.

“We decided to try source identification, and MST was emerging but we decided to try a different method instead,” he added.

PACD also used the tiered MST approach for three years, but their approach was too narrow, according to Morneau.

“Currently, the samples haven’t been from definitively positive sources, so we have enhanced our sampling protocol,” he stated, noting PACD will be focusing on livestock.       


Quintanilla stated he thinks MST isn’t the best approach when there is a known E. coli source.

“CCCD is constantly observing wildlife, and we know that agriculture is a huge sector in the area, so MST isn’t always necessary,” he said.

He also mentioned MST has spatial and temporal limits.

“In Gillette, there is a sewer treatment plant, and we know there is human waste coming out of the area, but when CCCD samples downstream, there isn’t any trace of human sources,” explained Quintanilla.

Morneau also voiced his concerns with the sensitivity of the human marker tests, but PACD is moving forward in the belief there isn’t many human sources of E. coli.

“PACD is also concerned about the results between Microbial Insights, a lab in Tennessee, and the Wyoming Public Health Lab because the numbers were different,” he added.

Morneau concluded, “Just because there aren’t positive hits doesn’t mean there’s nothing to be learned. Negative hits are helpful, too.”

Heather Loraas is assistant editor of the Wyoming Livestock Roundup and can be reached at This email address is being protected from spambots. You need JavaScript enabled to view it..

According to the Wyoming Department of Environmental Quality (WDEQ), there are eight bodies of water in the state listed as impaired due to elevated presence of selenium. 

Lisa Ogden, Natrona County Conservation District manager, was a featured speaker at the inaugural Wyoming Association of Conservation Districts Watershed Conference, held in Casper Feb. 20-21, and presented on the dangers of selenosis in animals and how we can prevent it in our water systems.

Ogden was one of a variety of presenters who discussed projects to improve local watersheds at the conference. 

What is selenium 

Selenium comes from the Cody Shale that underlies much of Natrona County and is readily transported through our waterways,” said Ogden. “As per WDEQ impaired waters list, selenium in water bodies comes from both natural sources and irrigated crop production.” 

She explained selenium is a heavy metal, which makes it a high priority pollutant according to the Environmental Protection Agency (EPA). The metal is soluble in water, allowing it to easily travel throughout bodies of water. 

“It is the general consensus that irrigated crop production is the main cause of selenium in Wyoming waters,” said Ogden. “Precipitation and irrigation of selenium-rich soils can dissolve and mobilize the metal to the surface and ground waters.” 

“Selenium can bioaccumulate and form deposits in the topsoil,” she explained. “The metal is particularly concentrated in areas of pooled waters, such as ponding from flood irrigation or wetlands on selenium-rich soil.”


“Selenium is an essential trace mineral used to help the body make antioxidant enzymes, but too much of it can result in selenosis,” according to Ogden. “Selenosis has been documented in aquatic plants, invertebrates, reptiles and amphibians, as well as mammals including livestock, wildlife and humans.” 

She noted the standards for chronic and acute poisoning in animals are much lower than that of humans. 

“Animals have a much lower tolerance to selenium, especially aquatic animals,” she said. “EPA lists the chronic and acute standards for aquatic species at five and 20 micrograms respectively, while the human drinking water standard set by the EPA is 50 micrograms.”

She described the signs of livestock and wildlife selenosis as loss of hair, mane or tail, rough hair coat, sloughing of hooves, reduced reproductive performance, poor weight gain, hoof or horn changes, lameness and death. 

The signs for aquatic creatures include reduced egg hatchability, embryonic death and deformities, deformed or missing body parts, emaciation and death.

Minimizing selenium

“Research has shown flood irrigation has a stronger correlation to high levels of selenium than sprinklers,” according to Ogden. “Conversion from flood to sprinkler irrigation is not only more efficient but minimizes transport of selenium.” 

Ogden noted practices such as lining or piping ditches can also minimize selenium transport. 

“We also want to minimize development on wetlands and on soil rich in selenium,” said Ogden.  

She noted the success in delisting the North Platte River from the impaired water bodies list can be attributed to standard testing protocols. 

“Without good data, we have nothing,” Ogden said. “We don’t have the right to list, delist or claim something is good or bad without good data. Water quality data from 2012-17 had to pass rigorous testing from multiple organizations to delist the North Platte.” 

“As of 1995 only 10 percent of irrigated fields in the Kendrick Project Area were irrigated by sprinklers,” said Ogden. “The rest were irrigated by inefficient flood irrigation.” 

“We are happy to report since 2012, we have converted 1,200 acres from conventional flood irrigation to more efficient sprinklers, 70,000 feet of earthen conveyance ditch to pipelines and have made numerous stock wells, tanks and developments,” said Ogden.

Callie Hanson is the assistant editor of the Wyoming Livestock Roundup. Send comments on this article to This email address is being protected from spambots. You need JavaScript enabled to view it..