Testing and Improving Forage Quality

A breakdown of how forage testing works, how to read your results, and how to improve forage quality.

Posted by Brooke Loeffler on Jan 31, 2024 5:17:48 PM

Forage, as the bulk of your animals’ diets, represents one of the biggest investments you make for their health and production. Forage testing helps you make more informed and financially safe decisions on feed rations, mineral programs, and pasture management. Hay quality varies much more than other agricultural commodities, so consistent testing is a great way to prevent deficiencies and imbalances in your animals before they start. Whether you grow forage to sell, or feed to your own animals, testing will help you gauge quality for greater profit and healthier winter feeding rations. Let’s learn more about forage quality testing and what to do with the results.

Jump to Section

| What do Forage Tests Measure | When to Test | How to Collect Samples | Understanding Test Results | What to do After Testing |

What Does Forage Testing Measure?

Forage testing measures the nutritional and market value of pastures, silage, or cured and dried forage, like hay. As the major source of energy, protein, fiber, vitamins, and minerals (especially during the winter season), forage quality directly impacts the health and production of any sized livestock operation. Most forage tests measure:

  • Protein- through the total nitrogen in the plant matter
  • Energy- fiber content and quality
  • Moisture- percentage of dry matter

These testing categories are broken down into different metrics (see Understanding Forage Test Results below) that can help you:

  • Prevent nutrient and mineral deficiencies
  • Maintain energy balance
  • Increase energy input for weight gain and lactation or gestation support
  • Protect your livestock from mold, toxic levels of nitrates, and other feed toxins.

Helpful Tip! Don’t just rely on chemical forage testing alone. Visual inspections of pasture, silage, and hay quality should always be combined with forage testing results. Keep reading to learn how to perform a visual inspection of your forage quality. 

Forage Mineral Levels

Complete forage testing should also measure mineral levels in your plant matter. Labs that only use near infrared reflectance spectroscopy (NIRS) and not “wet chemistry”, may not provide minerals in their results. Minerals are essential in powering the systems your animals use to break down plant matter. For this reason, you may need to specifically request macro and micromineral levels from your preferred testing lab.

What Affects Forage Quality?

There are a lot of factors that influence forage quality:

  • Soil health- balanced macro and micro (trace) minerals, pH levels, organic matter, soil-based organism activity
  • Plant species and variety- mixture between grasses and legumes which have different levels of structural and non-structural carbohydrates. Legumes typically have more protein and fiber than grasses. (Click to learn more about the balance of fiber and carbohydrates in ruminants).
  • Plant leafiness- leaves have more non-structural carbohydrates and protein than stems.
  • Plant maturity- as plants mature, they have less digestible energy, so more mature plant matter can test poorer than younger plants.

Plant cell maturity and forage quality

  • Harvest method- leaf loss during harvest will result in lower feed quality
  • Storage conditions- incomplete ensiling and incorrect moisture levels will dramatically lower forage quality and increase the risk of mold and other toxins
  • Growing environment- sunlight exposure, moisture levels, and temperatures affect plant quality. Heat stress can increase lignin levels, heavy rains can damage forage quality and strip soil nutrients, and extreme weather can cause harvest delays for more mature (less digestible) forage results.

When Should I Test my Forage?

No matter when you collect your samples, they should be mailed and analyzed as soon as possible. Storing or freezing samples will increase delays and give you less accurate readings. Mailing early in the week and avoiding mail holidays will give you better results as well.

When to Test Pastures and Soils

Most Ag Extensions recommend testing soil in the fall and waiting at least 3 months after you have applied any amendments. Additional testing in the spring can also be helpful if your herd has struggled with grass tetany

When to Sample Hay Bales

Taking a sample immediately after harvesting can give you important information about the quality of your pasture and soil health. However, a lot can happen to hay quality during handling and storage, including leaf loss, mold growth, and nutrient leaching. That means testing results can be different from the time samples were taken compared to when you start using it as feedstuff.

If you want the most accurate reading on the actual feed value of your forage, test closer to when it will be incorporated into feed. Comparing these 2 testing results can help you see the storage losses that occur after harvesting. If you are purchasing forage from a supplier, make sure to ask for the most recent sample results, so you have the clearest picture before planning out your feed rations.  

When to Sample Silage

Silage samples should be taken after fermentation is complete. Testing silage too early in the ensiling process can result in high, even toxic, levels of nitrates.

How to Collect and Submit Forage Samples

It is recommended to choose a local lab that is certified by the National Forage Testing Association (NFTA). Each NFTA approved lab may have slightly different sample collecting guidelines, so be sure to check with your facility of choice, to prepare your sample correctly. 

Testing Pasture Quality

Most pasture testing is done through soil samples. Take samples that are representative of your general pasture and not from high nutrient areas where waste is present like: water troughs, feeding areas, other animal gathering areas, ditches, etc. For larger pastures, collect at least a dozen samples and thoroughly mix together in a clean container before packaging and mailing. Did you know? Soil testing can be completed a lot quicker than other forage tests, especially when using Redmond’s Soil Test Kit. Our easy-to-use kit gives you thorough, digital results in 6-8 days plus recommendations tailored to your exact results. Click to learn more about testing your soil

Many soil testers have enjoyed the ease and speed of Redmond’s Soil Test Kit…see how Homesteading expert Jill Winger used hers:


Collecting Windrow Samples

You can also take fresh or drying forage cuttings from windrows. Multiple samples throughout the entire field will help you get an accurate representation of overall quality. Take samples from several different locations, then cut these sections into 1 inch pieces and mix samples together in a clean container before packaging.

Collecting Hay Bale Samples

Organize your hay bales into “lots” so you can get a representative sample from each lot of hay. Hay can be grouped into lots by:

  • Plant type
  • Cutting dates
  • Plant maturity
  • Curing or storage conditions
  • Weed contamination levels, and more.

Using a sharpened bale core sampler, collect and mix a minimum of 12 cores per lot. Round bale samples should be taken from the rounded side into the center of the bale. Square bales should be samples from the middle of the butt end. Once samples are collected, mix together in a clean pail, then bag with as much air removed as possible. Label your samples carefully so you remember which lot they came from.

Farmer takes a hay bale sample to test forage quality*Image courtesy of North Dakota State University

Collecting Silage Samples

For silage sampling, take handfuls from around 10 different locations in your storage until you have about a 2 gallon sample. Take extra care with larger bunkers or piles and use tools or loaders to help you safely get samples from different locations within the silage. Mix each handful together in a clean container and package in a labeled plastic bag. 

Visual Forage Inspection

Chemical testing and visual inspections compliment each other and should be used together. Visual inspections use sight, smell, and feel for palatability problems that your animals won’t like. Looking for qualities like leafiness, softness, color, and smell are subjective, but are still important for measuring forage quality. Oklahoma State Extension has created a forage score card where you can combine chemical results with visual inspection results.

Understanding Forage Test Results

When your forage test results arrive, you will have a number of metrics, abbreviations, and acronyms to consider:

Understanding forage testing results

Total Nitrogen (TN)

Total nitrogen measures how much true protein and non-protein nitrogen is found in your forage. Total nitrogen percentages will tell you the amount of crude protein (CP) by multiplying TN by 6.25. Crude proteins contain essential amino acids and nitrogen your animals and their rumen microbes need.


2 types of fiber are measured in forage tests: neutral detergent fiber (NDF) and acid detergent fiber (ADF). These readings break down how much energy your animals can derive from the plants tested.

Neutral Detergent Fiber:

NDF measures the total fiber from the structural parts of the plant and shows how much forage will be consumed.

  • Low NDF = more energy available to the animal.
  • High NDF = poorer quality feed and less energy for the animal.

Acid Detergent Fiber:

ADF shows the least digestible parts of the plant.

  • Low ADF = good digestibility.
  • High ADF = poor digestibility.

Fiber measurements are also used to calculate the relative feed value (RFV) of your forage. RFV is not a specific nutritional metric, but combines data from the NDF and ADF into a single number that is used to determine market value. This is frequently used by forage producers as a simple way to compare hays, but should be used with a range (of ± 5 points) since NDF and ADF can naturally vary.

Total Digestible Nutrients (TDN)

Total digestible nutrients (TDN) is one way to measure the energy value of a forage and is derived from the ADF. TDN can sometimes over-estimate energy levels because it does not take into account natural energy losses that happen during digestion (due to heat and gas creation).

Net Energy (NE)

Net Energy (NE) is another way to measure the energy value of a forage, and only shows the energy that is useful to the animal (not the energy lost to waste, and excretion). NE is helpful for showing how much energy is left after digestion to help with pregnancy, weight gains, and lactation.

  • Net Energy-Maintenance (NEm): the energy value in the forage used for maintaining a normal function and weight
  • Net Energy-Lactation (NEl): the energy value in the forage available for milk production
  • Net Energy-Gain (NEg): the energy value in the forage available for weight gain and improving body condition scores


Moisture and dry matter percentages are measured simultaneously. Forage samples are dried in an oven until a constant weight target is hit. The final dry weight is divided by the original weight to calculate the dry matter %. (100 - dry matter % = moisture %). Hay should be stored with a moisture % of 15-20 percent. High moisture levels cause mold, bacteria, feed toxin growth, and also increase spontaneous fire risk. Silage contains a higher moisture percentage but, if sealed properly, will be exposed to less oxygen and proper fermentation protects it from contamination.

What to do After Testing Your Forage?

Once you receive your results, you can make more informed decisions about feed rations, pasture management, and mineral supplementation. 2 major steps can now be taken: amending soil and pastures, and adjusting livestock feed and mineral programs.

Soil and Pasture Management (feed the soil, not just the plants)

Building healthy soil and pastures takes time but is well worth the effort. If your animals are grazing live pasture, if you harvest and store your own forage, or if you harvest your forage crops to sell…look beyond just nitrogen, phosphorus, potassium (NPK) fertilizers. Feeding your soil will create microscopic nutrient factories that, in turn, feed your plants more efficiently than chemical fertilizers alone.

  • Amend with a broader profile of macro and micro (trace) sea minerals to wake up the biology in your soil so they can break down nutrients into forms your plants can use. 
  • Amend with humates and volcanic conditioners to increase the nutrient storage of your soil, so your plants can trade for what they need.

Over the course of 4 years, Redmond teamed up with AGRES in Wisconsin to see what amending with a blend of our sea minerals and volcanic conditioner (Redmond SR 65) would do for alfalfa forage quality. The Redmond fields consistently showed higher TDN and RFV levels than other fields using chemical fertilizers:

YEARS 1 & 2

“Redmond SR 65 could be helpful in raising the feed quality of alfalfa. NPK fertilizer did not have have the same effect…SR 65 outperformed…and combined with manure appears to be a viable option for plant quality and yield.” -AGRES Wisconsin

“It appears that Redmond along with manure is a great option for feed quality compared to regular fertilizer.” -AGRES Wisconsin

YEARS 3 & 4

“The overall feed quality again improved with the Redmond application as indicated by lower NDF and higher protein, sugar, RFV, TDN, and NEL.” -AGRES Wisconsin

“Once again, feed quality under the Redmond Treatment (lower NDF, higher RFV and TDN). Yield also slightly increased with Redmond.” -AGRES Wisconson

Here at Redmond, we are always working hard to find new ways to share our rich sea and volcanic mineral deposit. In addition to our SR Blends of minerals and volcanic clay, we are proud to offer our Mineralyte family of soil amendments. Mineralyte Foundation, Build, and Grow all offer powerful benefits to bring life back to your soil and build quality into your forages and crops.

Improve forage quality

Animal Feed and Mineral Programs

With forage testing results in hand, you can also make adjustments to the feed and minerals you are offering your animals. If your forage quality results are low, extra supplementation will be needed to prevent deficiencies.

  • Resist the temptation to switch to heavy mineral mixes that have a low salt to mineral ratio. These mixes are less palatable to your animals and can increase excreted mineral waste.
  • Higher salt to mineral ratios that are carefully fortified and balanced for each species needs will put minerals to work, not to waste.

The nature balanced profile of our sea minerals mirrors levels found in healthy blood, both in type and concentration. That’s why our products so efficiently replenish blood mineral levels without all the waste. With this foundation of delicious electrolytes and trace minerals, our animal health experts carefully mix minerals to match each species needs and common deficiencies.

Learn more about what Redmond can do for:  

Give us a call at 866-709-3192 to see how Redmond can build health back into your forage and livestock and get you back to what you love about farming!

Back To Top