Posted on February 10, 2020 by maggielberger

By Lacey Newlin, 580-748-1892, [email protected]

Ruminants can utilize sources of biomass that other meat producing animals, such as fish, pigs and chickens, cannot. Ruminal microbes can convert low-quality sources of protein into a more valuable source of indispensable amino acids. (Journal photo by Lacey Newlin.)

“There are some really highly educated people out there who are actively against the beef industry,” said Tryon Wickersham, associate professor of animal nutrition at Texas A&M University. “I don’t think there is going to be anything we can do to change that. I think they will be against everything we do, no matter how we do it, but that doesn’t mean we shouldn’t mount a defense or stop educating the consumers about the value we bring to their plates.”

Wickersham spoke recently at the Oklahoma State University Beef Conference in Stillwater, Oklahoma, in a presentation called “Beef’s job title.” He says beef’s job title is to be a protein upcycler, which means to improve the value of protein.

Tryon Wickersham, associate professor of animal nutrition at Texas A&M University, spoke recently at the Oklahoma State University Beef Conference about beef’s job title of protein upcycler. (Journal photo by Lacey Newlin.)

Wickersham says, on average, it takes 770 pounds of corn to get a beef animal ready for slaughter. Corn is the primary source of human edible protein, or HEP, we feed and the main competition for food sources between cattle and humans. HEP does not necessarily mean tasty protein, but it is protein a person could consume. For example, grass is a source of non-HEP. Soybean meal, though we would not want to consume it, is a great source of HEP. Some people challenge agriculture for raising corn-fed cattle and believe we should be feeding all that corn to humans.

“If we didn’t feed corn to cattle, we wouldn’t compete with humans for that much food,” he said. “To justify corn-fed beef, we have to be able to say it is a better use of corn to feed it to cattle instead of children.”

He says children are used in his model because they have high amino acid requirements and they grow rapidly. The 770 pounds of corn we normally feed to one beef animal would meet the indispensable amino acid requirements of three children, according to Wickersham. Indispensable amino acids must be consumed in a diet to meet your protein requirements. If a child does not consume them, growth will be stunted.

“We don’t think a lot about stunting in the United States, but it’s a real problem in the world,” Wickersham said. “The world is not deficient in calories, it’s deficient in protein and other micro-nutrients and beef happens to be a really good source of those things. If you want to be a vegetarian in the United States you can, and you can meet your requirements and not be deficient, but not everyone is in the United States.”

Wickersham says corn is also high in calories, so those children would have to consume a lot more calories to meet their amino acid needs. In fact, it would be essentially impossible for a child to eat enough corn to meet their requirements.

On the other hand, if we feed the corn to cattle, through the value of protein upcycling we could feed 17 children and easily meet their protein requirements by feeding that one beef animal the 770 pounds of corn. Furthermore, ruminants can utilize sources of biomass that other meat-producing animals, such as fish, pigs and chickens, cannot.

“We’re really dependent on ruminal microbes to convert low-quality sources of protein into a more valuable source of indispensable amino acids,” Wickersham said. “Our animals can eat things that those other animals can’t and convert them into steak.”

Balancing the pillars of sustainability

Another method Wickersham uses to measure protein upcycling is net protein contribution or NPC. It estimates how a production system is contributing to meeting human protein requirements. Wickersham says this metric does allow us to address social sustainability. Sustainability is built on three pillars: social, environmental and economic sustainability. Wickersham says producers cannot pick just one pillar to focus on, they must balance them all.

“The beef industry does a really good job of addressing economic sustainability because everyone wants to stay in business,” he said. “We think about environmental sustainability indirectly as a result of improving economics. However, we rarely think about social sustainability of beef cattle production.”

According to Wickersham, methane production and HEP consumption are inversely related. The more HEP we feed cattle, generally methane production goes down. Conversely, if we feed them less HEP, methane goes up.

“We want them to balance each other,” Wickersham said. “We don’t want to go too far down on NPC. We want to have something counter balancing and pushing against NPC, so we are making the best decisions for the environment too.”

Another important figure is protein quality ratio or PQR, which determines if we are improving the protein quality of the product produced. As an example, the input PQR of corn is 36.8 and the output of beef is 112, by the end of the process, the beef animal has improved the protein quality three-fold. Wickersham says corn is about as bad as you can get when it comes to HEP and PQR and beef is at the best. Beef is a fixed biology; we cannot change the amino acid profile for the output. We can, however, change the input.

“We want the protein produced to be better than the protein we fed,” Wickersham explained.

Wickersham says we can determine if beef is competing with humans for HEP if we multiply HEP by PQR which will equal the NPC. If it is one or above, it is contributing to the human protein supply. Beef is usually around three, but at times it rises or falls, depending on phases of the beef cycle.

Wickersham says beef has a really great story to tell, but most of the time we fail to tell that story very well. He says NPC is a useful tool for defining the value of beef production systems.

“It gives us social sustainability and allows us to tell a compelling story that beef cattle are producing improved-value protein,” Wickersham said. “It also gives us an environmental sustainability and efficiency of nutrient utilization and provides us a way of capturing the benefit of having cows grazing our pasture. That brings value to humans. We are taking that grass that we have no way to utilize and turning it into steak.”

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