Study focuses on feeding beef cattle algae co-products

COLLEGE STATION – Algae typically is not associated with cattle feed, but a group of researchers in the Department of Animal Science at Texas A&M University has found interesting results that may change this in the future.

Animal Science graduate student Merritt Drewery, Dr. Tryon Wickersham, associate professor, and Dr. Jason Sawyer, associate professor, are working to determine the feeding value of post-extraction algal residue, the co-product resulting from algal biofuel production. This research is part of a bioenergy program led by Texas A&M AgriLife Research  and is supported by the Department of Energy through the National Alliance for Advanced Biofuel and Bio-Products.

“One of the key factors in the success of algae as a biofuel is finding suitable markets for the residue. The beef cattle industry is an established user of co-products such as distillers’ grains, glycerol, cottonseed meal and soybean meal,” Wickersham said. “We may be able to use post-extraction algal residue as a source of nutrients for all classes of beef cattle.”

Through a series of studies completed this June, researchers determined palatability and nutrient availability of post-extraction algal residue to cattle fed a forage diet, with the primary objective of determining the effectiveness of post-extraction algal residue as a protein supplement. In a companion project, researchers located at the Texas A&M AgriLife Research and Extension Center at Amarillo, are evaluating the inclusion of post-extraction algal residue in feedlot diets.

“The first project tested palatability,” Drewery said. “We offered 12 different supplements with different levels of algae inclusion. We measured how long they took to completely finish the allotted supplement.”

Surprisingly, the steers were not picky eaters as they widely accepted the algal residue in a processed form, the researchers said.

Supplements with algae were offered at 2.2 pounds per day and the steers were given an hour to consume them. The algae co-product, which is 20 percent crude protein, was blended with dried distillers’ grains or cottonseed meal at 0, 20, 40, 60, and 100 percent blends.

“The algae could be blended up to 60 percent with distillers’ grains or cottonseed meal without significantly altering palatability,” Drewery said. “The study results show a 54 percent completion rate and lower rate of consumption when the algal co-product was offered alone.

“In the second project, we compared supplemental post-extraction algal residue and cottonseed meal and found forage intake and utilization were stimulated to a similar extent when algae was used.”

Angus steers in this project had free choice to low-quality hay (4 percent crude protein), and supplements were administered ruminally to ensure complete consumption.

“We administered the supplement in the morning just prior to feeding hay,” Drewery said. “Supplementation rate was based on steer body weight and previous research conducted at Texas A&M.”

“This project indicated post-extraction algal residue is an effective source of supplemental protein for cattle consuming low-quality forage,” Wickersham said.

In the third experiment, steers were allowed access to supplements of post-extraction algal residue or cottonseed meal over the duration of an entire day.

“We were worried they wouldn’t eat the entire amount of the algae supplement this time around, but there weren’t issues with supplement refusals,” Drewery said.

In visual observations, the steers would eat half of the algae supplement within 10 minutes, finishing the rest sometime during afternoon hours.

“They would also eat hay and drink a lot of water after consuming the algae,” she noted.

The final project was initially designed to test a final blend of post-extraction algal residue and other feedstuffs to create a complete supplement.

“However, based on our observations in projects one and two, we were confident steers would consume post-extraction algal residue without the addition of other ingredients if given a long enough time to consume the feed,” Wickersham said.

There is additional information to be determined, he added, including determining the market value of post-extraction algal residue in the beef industry compared to distillers’ grains and cottonseed meal, common ingredients found in cattle feed today.

Also, the researchers are attempting to get the algae in a form that is “easily deliverable to cattle.”

“We are trying to identify the best processing method to feed it to grazing cattle,” he said. “The algae co-product is high in salt, as the algae is a saltwater product.”

“Crude protein is 20 percent, but half of the chemical composition is ash,” he said. “In comparison to cottonseed meal, you have to feed twice as much algae to get the same effect. In the beef industry, traditionally the cow-calf operator pays more for protein that the feedlot side. That’s something we have to consider. Additional research is required to fully explore the value of feeding algae to grazing cattle.”

In addition, future research will evaluate feed delivery systems for post-extraction algal residue as well as different types of algae and production processes.

“While algae as biofuel is in the developmental phase and it will likely be a few years before large quantities of post-extraction algal residue become available to beef cattle producers, this research can immediately be used by algal biofuel producers to estimate the market value of post-extraction algal residue,” he said.

Wickersham concluded, “long-term, if algal biofuel production reaches commercial scale, our research will create a foundation for future research focused on using post-extraction algal residue as a source of nutrients in beef cattle systems.”


For more information regarding news from the Department of Animal Science, College of Agriculture and Life Sciences, Texas A&M University, please contact Courtney Coufal at or (979) 845-1542.

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