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UNL staff discuss protein supplementation in low-quality forage scenarios

by Wyoming Livestock Roundup

The University of Nebraska-Lincoln (UNL) BeefWatch podcast dated Nov. 9 welcomed co-authors Nebraska Extension Beef Systems Educator Hannah Smith and UNL Beef Cattle Nutritionist, Range Production Systems Travis Mulliniks to discuss their UNL BeefWatch newsletter article titled “Protein supplementation: What should I know before purchasing.” 

Protein supplementation
on low-quality forage 

From a fundamental standpoint, producers are not only feeding a beef cow, but also feeding microbes in the rumen. During winter grazing of dormant forages, daily energy intake can be a limiting factor for cow performance. 

“From a low-quality standpoint, we have to make sure we’re meeting the requirements of the microbes first so the cow can digest and utilize the forage [she is consuming],” says Mulliniks. “Once forage crude protein (CP) gets to seven percent or lower, producers can start to see intake issues.” 

Feeding a protein supplement provides for microbes and increases energy intake, he adds. 

“The cow now has the ability to consume and digest forage and increase energy,” he says.  

In low-quality forage scenarios, Mulliniks encourages producers to think about meeting the needs of microbes in the rumen, and then meeting the forage needs of the cow. 

When there is not adequate protein in the forage to meet the protein needs of the microbes, CP typically falls below seven percent, he mentions.  

Feeding a protein supplement will generally improve the energy and protein status of cattle by improving digestion and intake. By feeding microbes in the rumen, producers can increase microbe activity, which then increases the cow’s ability to eat more forage. 

“Forage has to get to a very small particle size before it can leave the rumen, so it takes so much longer if there is not enough protein in the diet,” he says. “While these forages can be in the rumen for 42 to 72 hours, producers really want to enhance the ability of those microbes to digest forage and get it out of the rumen quicker.” 

Supplemental protein options for classes of cattle 

Protein supplements can be offered to cows daily, three days a week or once per week to maintain adequate performance. Producers can utilize cake cubes, grain mixes, blocks, tubs and forages, all ranging in overall CP content. 

Producers need to keep in mind the importance of changing feedstuffs or protein types across all classes of cattle, including calves and first- or second-calving heifers versus an older mature cow. It’s important to economically analyze cost per pound of nutrients, Smith says. 

As a rule of thumb, producers can feed 0.3 to 0.6 pounds of CP per day during late gestation to mature cows to ensure the cow maintains performance and fetal growth. 

“Protein supplementation is very complicated,” says Mulliniks. “It’s very important to consider the class of cattle being fed because producers can have two very different protein sources and have two different responses from feeding the cow.” 

Types of protein

Due to rumen fermentation, not all proteins are equal. CP can come from natural protein sources or non-protein nitrogen sources such as urea, biuret and/or a mixture of the two. 

Another CP option is rumen undegradable protein (RUP). This protein is protected from degradation in the rumen and will be absorbed and utilized by the cow. 

“There’s a lot of research showing RUP sources have a much bigger benefit on the reproductive processes of getting cows pregnant,” he says. “There’s a lot of benefits to RUP sources as well – it’s important to understand the dynamics of when one type works and one type doesn’t.” 

A few examples of natural proteins include alfalfa hay, distillers’ grains and soybean mills. Non-protein nitrogen includes urea used in cooked molasses tubs, liquid molasses and biuret. 

“Urea and biuret have their own place, but they are highly degradable,” mentions Mulliniks. “They cheapen protein costs and they are a major protein source to a lot of liquid feeds and lick tubs – there is a good place for them, but the challenging part is they are highly degradable.”

When grazing a low-quality forage, a lot of highly degradable protein is wasted, and in scenarios where producers are feeding a true protein, there is less waste and better utilization of microbes, he notes.  

“Just because something is cheaper and has better protein, doesn’t mean it’s a better choice from a cow performance aspect,” he adds. “It can make it a very complicated decision.”

In developing a protein supplementation strategy, it’s important for producers to consider what the goal of feeding the protein supplement is and to remember not all protein sources are equal. 

“With protein supplementation, producers have a lot of flexibility,” concludes Mulliniks. “Cows are extremely efficient, especially in low-quality forage situations with utilizing and recycling of protein – it gives a lot of flexibility with supplementation strategies.” 

He notes one way to get around high feed, fuel and delivery costs is through frequency. If producers are feeding up to five times a week for protein needs, producers can cut costs by feeding twice a week while maintaining the same performance.  

In addition, when feeding a starch-based supplement, such as corn or milo, producers will need to feed every day, but if it’s fiber based, producers can feed every other day. 

“As a whole, there’s a lot of flexibility when it comes to protein supplementation with how often producers can feed protein supplements and still have the same performance,” he says. “With cost being high, no matter what producers are feeding, there will always be waste – understanding waste is very important in controlling cost and making sure producers are meeting protein needs.” 

Brittany Gunn is the editor for the Wyoming Livestock Roundup. Send comments on this article to

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