Beef Tips

February 2020 Feedlot Facts

“Cow Nutrition: Protein, Energy and Forage Availability”

By: Justin Waggoner, Ph.D., Beef Systems Specialist

Protein supplementation is important, but there is more to cow nutrition than simply ensuring that the cow’s protein requirements are met and that we have supplied the rumen microbes with sufficient nitrogen to digest the low-quality forages that sustain our cows through the winter months. Most cattle producers know and appreciate the value of protein supplementation, but often overlook energy. Although, protein supplementation does impact energy status by enhancing digestibility and intake of low-quality forages.

The benefits of protein supplementation are not fully realized by the cow if forage availability (supply) is limited. Both protein and energy requirements steadily increase during gestation and post-calving. Thus, there are many production scenarios, where both protein and energy may become limiting or where energy becomes more limiting than protein, minerals or vitamins.

I have found that producers often attribute negative production outcomes, such as higher percentage of open cows, with their previous protein supplementation protocols or mineral and vitamin deficiencies. Protein, minerals and vitamins are important components of cow nutrition, but in many cases energy deficiency may be the more likely cause. Energy status of grazing beef cows is essentially a function of forage availability in most situations.

The most basic way to think about forage availability is to ask yourself “Does each cow have all she can eat in the pasture or field?” If the answer to that question is “No” then energy is likely the most limiting factor in your production system. There are many ways to address situations where energy has become limiting. Feeding hay to replace grazed forage, moving to a new pasture or field of stalks or feeding combination supplements that provide both protein and energy are all strategies that may used to increase energy status.

For more information, contact Justin Waggoner at

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