Alfalfa

Alfalfa Production.

Production of premium forages is extremely complex. One of the top and most widely recognized measures of forage quality is the amount of crude protein it contains. Crude protein has a large impact on animal digestive health and productivity. Read on for more information on crude protein, why it’s important and what percentages are ideal in different types of forages.

What is crude protein in forages?

Protein itself is an essential element of livestock nutrition, and there are many sources from which it can be derived. However, the term “crude protein” does not refer to or measure how much protein is present in forages. So what exactly is crude protein? Crude protein is a chemical analysis of the forage that calculates the amount of nitrogen, which is the building block for amino acids that form proteins. This is then used to estimate the amount of true protein and non-protein nitrogen.

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Proper crude protein levels are essential in forages for the many types of livestock that rely on them for nutrition. When the percentage of crude protein is low, the bacteria responsible for digestion cannot sustain adequate levels to process forage. Ultimately, the animal’s intake and digestibility are reduced. It is important to note that although CP is important and a commonly used measure of feed quality, it should not be used to estimate energy value. This is best represented by TDN, which we will cover in depth as we continue with the Forage Nutrition Series.

How is this percentage increased?
Forages that don’t contain proper amounts of crude protein will require supplementation by protein nutrients in order to return bacteria levels to a sustainable level. Forages that are effective as supplements to primary feed include soybean meal, cottonseed meal and corn gluten feed. However, considering the cost of protein supplements, the smart financial choice is to make purchasing decisions based upon crude protein in the forage – eliminating the need for supplements.

To calculate crude protein, total nitrogen is determined, then multiplied by 6.25 (there is 1 part N for every 6.25 parts protein in most forages). This number reflects a forage’s potential to provide protein that certain livestock require.

Climate & harvest effects on crude protein

Crude protein concentration does vary by season and maturity. Cooler environments will produce forages with higher levels of CP as compared to warmer months. Crude protein also decreases as the forage ages and fiber content increases, and in excessively rainy conditions where nitrogen is leached out after the forage has been cut. There are many fertilizer options available to increase the nitrogen available during growing.

Advantages of Alfalfa

• Versatile use Alfalfa can be ideal on farms where it can be used for hay, silage, or grazing. Virginia workers studied grazing alfalfa systems based on need and environmental conditions. Systems of grazing the early spring growth provided quality feed and delayed the first hay harvest until more favorable weather conditions for curing.
• Extended use of stand Grazing can extend the useful life of a stand by a year or more for old alfalfa hay fields where some of the stand has been lost or has become weedy. Grazing may also rejuvenate some stands by reducing grass and weed competition.
• Lower fertilizer expense Under grazing, over 80 percent of the plant nutrients ingested are returned as dung and urine. Therefore, annual fertilizer needs are lower than where plant nutrients are removed from a field as hay. However, manure distribution is not uniform in a grazing environment because of concentration around water points and shade.

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