Protein Supplements in Winter: How Angus Producers Can Use Them Better

Protein is the most familiar winter supplement. A USDA national study of beef cow-calf operations, NAHMS Beef 2007-08, reported that 74.7 percent of operations fed protein supplements to beef cows during the preceding 12 months, according to its nutrition summary. That is an older survey, and a different figure than some you may see quoted, so treat it as a rough indicator. The key question is not whether most people use protein but whether it fits your forage and your cows. This guide explains when it pays and how to use it well.

Why protein matters in the rumen

Cows do not digest fibrous forage alone. Rumen microbes do the work, and the microbes need nitrogen. NDSU Extension explains in its advice on low-quality forage that microbial fermentation drops when forage crude protein falls below about 7 percent, which lowers digestibility and intake. Supplying protein then does double duty: it feeds the microbes, the cow digests more of the hay and eats more of it. Utah State University Extension reports that supplemental protein can raise dry matter intake by about 20 percent, and that where forage TDN is around 50 percent or higher and the cow is in decent condition, protein often corrects most of an energy deficit.

When protein does not pay

Not every pasture is short of protein. Missouri Extension says dormant tall fescue rarely falls below 7 percent crude protein, and that protein supplementation is generally ineffective in Missouri's cool-season systems, where energy is typically the limit. Buying protein for cattle that are short on energy, or short on forage quantity, wastes money. Missouri advises checking quantity first: pasture under about 4 inches suggests that intake is limited. Test your forage and look at body condition before choosing a supplement.

Choose the source

NDSU says a true protein supplement should be about 25 to 30 percent crude protein. Options include good-quality hay, oilseed meals and byproducts such as corn gluten feed and distillers grains. Non-protein nitrogen such as urea is cheap but less efficient with low-quality forage. NDSU gives limits of 0.05 pounds per day of urea for dry cows and 0.10 for lactating cows, and warns that a feed tag listing 10 percent NPN protein equivalent means about 3.6 percent urea. USU suggests that urea-based NPN should be no more than about one-third of total dietary protein. Follow label limits, and introduce NPN gradually.

Price it by the pound of protein

USU's illustrative figures show how product price misleads. Delivered alfalfa at 18 percent protein and $150 a ton cost about $0.42 per pound of protein. A 36 percent protein block at $880 a ton cost about $1.22, and a 30 percent molasses tub at $1,100 a ton cost about $1.83. Prices today will differ, but ranking by cost per pound of protein, with labor and equipment added, is the right habit. Missouri makes the same point and notes that a higher-priced 40 percent protein feed can be cheaper per pound of protein.

Feed it less often

Cows recycle nitrogen, so protein does not need daily delivery. USU says feeding protein every other day or three times a week is adequate for mature cows. Its example: 2.3 pounds three times a week replaces 1.0 pound daily. Missouri says protein can be fed as little as twice weekly at roughly 1 pound of crude protein per cow per day when protein is limiting. Fewer feedings save fuel and labor. Young and thin cows may need more frequent feeding, and energy supplements generally do.

Why cows sort themselves out at the feeder

One practical wrinkle is competition. When supplement is offered in a pile or a limited number of feeders, dominant cows tend to eat more than their share, and timid animals, often the young or thin ones that need it most, eat less. That makes the average intake look right while individual cows are over- or under-supplied. Spreading feed along a longer line, adding feeders, or sorting thin and young cows into their own group solves much of it. Check body condition on the shy cows, not the average cow, to see whether the program is working. Intake control also matters with self-fed products such as blocks and tubs, where consumption can swing with weather and with what forage is available, so watch actual use against the label.

Common mistakes

• Feeding protein without a forage test.
• Feeding protein when energy or forage quantity is the real shortage.
• Letting the dominant cows eat the supplement while thin cows go without. Spread feed out or sort groups.
• Comparing by price per ton instead of price per pound of protein.
• Skipping minerals, which are cheap by comparison.
• Exceeding urea limits.

A decision path

1. Check pasture height and hay quantity first.
2. Test forage for crude protein and TDN.
3. If crude protein is below about 7 percent and energy is moderate, protein is likely to pay.
4. If TDN is below about 50 percent, plan on energy as well.
5. Choose the cheapest source per pound of protein, counting labor.
6. Decide on feeding frequency and track body condition.

Our guide on supplementing beef cows covers delivery methods, and farm.fm's page on optimizing feed formulation adds ration basics. agriculture.directory can help you find local help.

The takeaway

Protein supplements are common because low-quality winter forage often runs short of it. They pay when protein is what is limiting. Test first, price by nutrient and watch body condition. Check with a nutritionist, since requirements change with stage and weather.