Fly larvae studied as potentially novel livestock feed under USDA grant

Merritt Drewery, assistant professor in the Department of Agricultural Sciences

The United States Department of Agriculture's (USDA) National Institute of Food and Agriculture (NIFA) has awarded Merritt Drewery, assistant professor in the Department of Agricultural Sciences at Texas State University, a grant to study insects as a potential alternative, environmentally sustainable feed source for beef cattle.

The $200,000 Agricultural and Food Research Initiative (AFRI) grant will support Drewery's project, "Black Soldier Fly Larvae (BSFL) as a protein source for cattle consuming forage."

The project addresses a growing agricultural need. Conventional livestock feeds, such as soy, demand significant resources to produce. Soy is also in high demand for human consumption, inviting unfavorable competition for livestock feed. By 2050, predictions indicate world population growth will result in a 58% increase in the demand for meat versus 2010, which will in turn drive up prices and increase pressures on natural resources necessary to meet this demand.

Alternative and potentially more sustainable feeds for beef cattle can help alleviate some of these challenges. Drewery's research has identified BSFL as a potential high-protein replacement for conventional livestock feeds. BSFL have high feed efficiency and can be grown on food and feed byproducts that would otherwise have an economic and environmental cost for disposal.

"Black soldier fly larvae is an attractive livestock feed," Drewery said. "They are easy to grow. They are high in protein. They thrive on food waste and feed byproducts that have environmental and cost issues associated with their disposal.

"In some cultures, insects are important sources of nutrition, but consumers in Western societies are not likely to accept insects into their diets," she said. "This indicates there will not be competition between the feed and food sectors."

BSFL have previously been evaluated as feed for fish and chickens. They have not yet been evaluated in beef cattle, so Drewery's project will feed different amounts of BSFL to cattle, along with the same amount of a conventional feed, such as soy, to serve as a comparison.

The study will evaluate how the different supplements impact feed intake and digestibility as well as document cattle feeding preferences when presented BSFL alongside other conventional feed options. Specialized equipment that mimics the cattle's digestive system will evaluate other nutritional characteristics of BSFL in the laboratory.

Cumulatively, the research trials will provide insights into how BSFL affects digestion in beef cattle and whether it can be recommended as a livestock feed or not. By assessing a novel feed that does not directly compete with existing crop production, is associated with low natural resource inputs and will not be accepted as a human food, Drewery's study may contribute to improving the long-term sustainability of beef cattle production.