Forage testing: why a test is the best route to go for your cattle

As hay and other forages make their way into your feed storage area this fall, you might want to consider forage testing. Forage testing has value for your operation, it can be a useful tool for maximizing livestock production and can minimize feed costs. Testing forages not only helps determine if livestock requirements are being met, it also determines whether you need to supplement or could mix off with lower quality forages to avoid overfeeding.

Forage analysis is useful when looking at inventories and planning for winter feeding. If forage quality is high enough, there may be an opportunity to mix it with straw, thus stretching supplies and lowering overall feed costs. If forage quality is lacking in certain nutrients, it will be necessary to bring in some type of concentrate product such as cereal grain, screenings, dried distillers grains or canola meal for example, in order to maintain body condition of livestock on feed.

Generally, forage analysis should include the following parameters: moisture, dry matter, crude protein, acid and neutral detergent fibre, calcium, phosphorus, magnesium, potassium and sodium. In addition to these, the analysis will include a variety of energy estimates which may be reported as total digestible nutrients (TDN), digestible energy or net energy. Each of these nutrients play a role in the overall quality of the forage being tested.

There are book values for many types of forages and other feeds, however, actual results can vary substantially and the cost of that variability can be high. If we balance a ration on book values and the energy value of your primary forage source was five percent lower than the book value, we could create a situation where pregnant females are losing body condition rather than maintaining or gaining the condition that we had prepared for. This is especially true as weather turns colder and females advance to the later stages of pregnancy.

Anti-nutritional factors can also be analyzed in forages. For example, kochia and brassica species such as canola, kale, turnip and radishes often contain high levels of sulphur. Testing for sulphur content provides the necessary information to determine safe feeding levels and avoid issues such as blindness, polio or trace mineral deficiencies. Flax and sorghum/sorghum-sudangrass hybrids may contain prussic acid, which can cause poisoning in livestock. Forages can be susceptible to mould and mycotoxins, which can reduce growth performance, cause feed refusal and impact immunity amongst other issues. Cereal greenfeed and some grasses can become contaminated with ergot, leading to lameness, sloughed hooves and tails, as well as abortion and reduced milk production. A forage test could be critical in maintaining the health of your herd over the winter.

There are different testing methods available. Near infrared reflectance spectroscopy (NIRS) uses different light wavelengths passing through a sample to interpret the kind and amount of nutrients present. Wet chemistry analysis (the gold standard for forage analysis) involves lab work and chemical testing. Wet chemistry analysis of large numbers of common feed samples is used to calibrate NIRS lab equipment. NIRS is often faster and cheaper but has limitations, especially with uncommon feedstuffs where a reference library may be small or unavailable. A basic feed test covering the parameters noted earlier will cost between $30 and $65 depending on the type of analysis and the lab. Testing for antinutritional factors or additional minerals will add to that cost. However, the overall cost of a forage test is small compared to the insight and useful information it can provide.

For more information about forage testing, borrowing a forage probe from your local regional office or other livestock related topics, contact your local livestock and feed extension specialist.