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0508 FG: Alfalfa hay grading and sampling for a quality product

Written by Denise McWilliams, Scott Bundy, Woods Houghton, James Duffy and Gary Hathorn Published on 17 Oct 2008


Alfalfa quality: The key to marketing a better hay product
Hay is one of the most versatile means to package and sell stored forage for animal feed.

Hay can be kept for long periods of time with little loss of nutrients when protected from weather. Many crops can be hayed successfully. Alfalfa, in particular, has successfully been used for specific ration supplementation and for specific animal markets.

Hay can be produced and fed to fit different farm or ranch needs using small to one-ton large squares, multiple sizes of round bales and even loose or stacked hay. Crops used for hay can also be managed in bales or wrapped and stored to prevent weathering.

Cut at different moistures, the crop may be used to produce balage or silage, giving the grower latitude of choice between feed product type and form. Hay can be produced, grazed or baled and fed with low bottom-line economic costs compared to other feed.

Operation costs, largely mechanization at first, range from minimal equipment needs for simple, direct grazing use up to complete mechanization. Intensive mechanization involves seeding, all haying equipment to bale, pick-up, store and deliver. Hay [...] can supply most nutrient needs for stocker units and is the most commonly stored feed in animal operations.

Most baled hay is pressed into packages or round bales varying from 35 to 2,500 pounds. Hay can be baled at moisture percentages above 25 percent if stored within silage bags for a balage product. Hay, however, is usually baled at around 18 to 20 percent moisture for safety. Low moisture prevents combustibility and molding, as well as loss of quality.

Harvest operations include mowing and curing the hay, then raking the hay into windrows and baling. Additional operations can be used in humid or high rainfall areas where hay curing is difficult within a short turnaround time, and crimpers may be used with applications of drying agents at baling. Baling into small round or square bales at 35 to 80 pounds has traditionally been popular but is labor-intensive, even with the current small bale stacking equipment.

Better mechanized harvesting equipment within the last 20 years has resulted in a more widespread use of large round or square bales up to 2,500 pounds, but many weigh in at about one ton (2,000 pounds). The advent of large bale use in new, bigger mixer-grinder units has also hastened the use of large bales, particularly at dairies and in feedyard operations.

The original standards, last modified in 1985, established grades on visual estimates using hay leafiness, percent green color, percent foreign matter, coarseness of stem and other qualities including odor, mold and dust.

However, these visual estimates are difficult to consistently substantiate. Visual criteria are not necessarily related to animal performance or feed quality. Indeed, different regional products may look similar but vary in nutritional value. Thus, hay standards were updated to provide a more qualified, standardized system across regions of the country and world.

Hay is now shipped not only across state lines but to different countries, making a standardized product evaluation essential. While current standards still do not require specific laboratory or digestibility nutrient analysis testing, alfalfa hay standards do provide a slightly more specific segmentation between classes of hay. This ensures fairer pricing and more specifically describes hay entering foreign trade and also provides a better estimate of feeding value prior to purchase.

Hay standards set in 1998 are still used to designate grade. The original federal grades were established in 1933, then revised in 1944 and 1949 under the Agricultural Marketing Act of 1946 and the Farm Products Inspection Act. The guidelines currently use crude protein (CP) percent, acid detergent fiber (ADF) percent and relative feed value (RFV) along with an evaluation of color, molds or weeds present.

Alfalfa is then placed in five quality categories:

•Supreme: very early maturity; prebloom; soft, fine-stemmed, extra leafy (factors indicative of very high nutritive content); excellent in color and free of damage

•Premium: early maturity; prebloom; fine-stemmed, extra leafy (factors indicative of a high nutritive content); green and free of damage

•Good: early to average maturity; early- to mid-bloom; leafy, fine- to medium-stemmed; free of damage other than slight discoloration

•Fair: late maturity; mid- to late-bloom; moderate or low leaf content and generally coarse-stemmed; may show slight damage

•Low: very late maturity with mature seed pods; very coarse-stemmed; could include hay discounted due to excessive damage and heavy weed content or mold

The supreme quality designation was established as a new category in 1998.

Some states have adopted additional regulations on hay standardization and have modified the categories; however, most states have simply kept the 1998 federal standards.

Some states have established additional criteria on alfalfa hay standards, but there is little uniformity. Due to this lack of uniformity, selling hay across state lines can at first be confusing. In addition, some states have a weed-free certification program that has added another set of criteria to certain certified hay sold in and out of that state.

Few states have implemented a weed-free certification program due to additional costs for color-coded twine used on certified bales and the need for multiple inspections at the field and for the final product. However, with this certification yet another sales class of alfalfa hay has emerged for marketing beyond the quality standards of supreme, premium, good, fair and low.

Hay quality is best measured by the amount and availability of nutrients in the hay. Current laboratory testing can quickly estimate protein, fiber and hay digestibility to help determine hay quality. The most concise test of quality, however, is animal performance upon feeding the product. Quality alfalfa hay will be easily consumed by the animals being fed and will increase or maintain animal growth and gain as desired.

Animal performance is determined by intake, digestibility and nutrient content as well as lack of toxic compounds within the hay product. Intake is supplemented by hay digestibility and nutrient content.

Hay must be digested and converted by the animal’s metabolic system. Some hay or hay mixtures are just naturally preferred by animals. Softer, leafier vegetation may be consumed faster than hay with more stems (less digestible and less nutritious) or hay that has lost leaves due to pest problems or with leaf shatter at baling.

The hay must also be free of harmful components that might limit animal intake. This not only includes toxic compounds within the hay or weeds that were also harvested but also dust or mold that may have accumulated within the hay product during baling, storing or at feeding.

Plant species and variety, seed quality, fertility, stage of maturity at harvest, as well as curing or handling conditions, are some of the alfalfa production elements that can also affect hay quality or the intake, digestibility, nutrient content and toxic compound content within the hay.

Plant species and variety will affect hay quality. The type of forage will impact hay quality, with legumes such as alfalfa generally higher in quality than grasses. Cool-season grasses are often of higher quality than warm-season grasses in hay products. Pure alfalfa usually also produces higher quality hay than an alfalfa-grass mixture; however, when properly cut and dried, a mix can still produce a high-quality hay product.

Perennials such as alfalfa, orchardgrass, fescue or even bermudagrass in the long run may be more economical as hay crops rather than annuals, if persistence and longevity of stands minimize establishment costs. But annuals such as sorghum-sudans, small grains or even ryegrass can be used effectively in haying operations for specific uses.

Choice of forage as well as variety can ultimately determine stand persistence, yield and quality. Choose varieties that meet the location and climate needs in alfalfa including recommended fall dormancy ratings, winter survival criteria, disease and insect tolerances, as well as grazing or haying variety suggestions to optimize your operation.

Seed quality of the crop planted can also make a difference in ultimate hay quality and operational costs. Use of certified seed ensures higher germination and potentially better stands for improved yield and quality.

Clean seed, seed not limited by weed seed, dirt or other contaminates, can ensure better quality hay as disease or competition from weeds on seed material do not limit the crop. Weeds can also limit hay quality by lowering product palatability and digestibility or even adding toxic or harmful contaminates within the hay.

Timing of planting at approximate dates ensures better success with seeding. Planning establishment around rain or irrigation, along with considering a better establishment in the spring or fall with cool- or warm-season species, can make a difference in seedling establishment and stand thickness as well as ultimate crop longevity and productivity.

Major and minor fertility needs for the forage must be met to provide a starting stage for success with seedling establishment and must continue for crop needs through the seasons on perennial plants.

Fertility will help maintain stands and further prevent weed encroachment or competition. Use of soil testing can determine fertility needs at establishment and in future seasons. Making sure seeds at planting are inoculated with viable rhizobium for root symbiotic nitrogen fixation can also help establishing seedlings and mature plants to begin fixing nitrogen.

Multiple cuttings or high rainfall can remove nutrients more rapidly. With simply nitrogen (N), phosphorus (P2O5) and potassium (K2O), alfalfa typically removes 56 pounds of N, 15 pounds of P2O5 and 60 pounds of K2O per ton of forage harvested.

With continued production, other nutrients may also be needed, particularly magnesium (Mg), sulfur (S) or even iron (Fe) in higher pH soils or where poorer quality irrigation water is used. In Western alfalfa fields, yield per acre (yield/A) may be limited unless nutrients are available for crop uptake when needed during the growth and regeneration stages.

Stage of maturity at harvest can also influence hay quality. As alfalfa grows from vegetative to reproductive, it becomes higher in fiber and lower in protein, digestibility and palatability. Even though yield increases with maturity, forage quality deteriorates. Timing hay cuts to take advantage of favorable growth due to optimum temperature and soil moisture conditions can increase total yield per acre.

Poor curing or weather and handling conditions can also lower alfalfa hay quality. Leaf loss and nutrient leaching from plant materials can occur with rain. Intense sunlight can reduce vitamin A content with plant bleaching. Excessive raking of dry, brittle hay can further lead to leaf loss. Conditioning of alfalfa stems, especially under poor weather conditions, might decrease drying time by a day and lead to less leaf and nutrient loss, but this processing step is not always necessary.

Indeed, hay plants at 80 percent moisture must lose about 6,000 pounds of water to result in each ton of hay at 20 percent moisture; however, drying conditions often can accomplish this in one to three days.

Thus, even the use of chemical conditioners such as potassium carbonates or sodium carbonates is rarely needed to reduce hay drying time. Use of width swaths or simply raking or tedding while hay is moist (at 40 percent moisture) and baling before hay is too dry (below 15 percent moisture) can hasten drying and reduce leaf loss.

Use of hay preservatives applied at baling are not needed if baling moisture is correct and rain does not fall on bales. Hay is safely baled at greater than 20 percent moisture on small bales and at 18 percent moisture on large bales, but should be stored in stacks at moistures below 18 percent (preferably at 16 percent or less) to prevent combustion. Hay preservatives, when applied at baling, can prevent excessive heating and mold growth when applied uniformly to higher moisture hay.

Examples of marketed preservatives are products from propionic acid or a mixture of propionic acid and acetic acid. Most products marketed today are buffered to be less volatile and to prevent some of the early problems of removing paint from balers, offensive odors and irritation to exposed skin of human hay haulers.

Even roughly handling alfalfa hay before feeding or mixing into rations can cause leaf loss and consequentially quality decrease. Even with small bales, the average bale has about 29 percent of its total volume around the outside 1-inch depth (average small bale at 14 inches by 18 inches by 30 inches); thus, leaf shatter from the outside parameter can make a difference in ultimate hay quality. With large round bales, the outer 4 inches contain about 25 to 30 percent of the total volume, making careful handling and storing a must to preserve hay quality by limiting leaf shatter losses.

Indeed, alfalfa production elements such as plant species and variety, seed quality, fertility, stage of maturity at harvest, as well as curing and handling conditions will affect hay quality, intake, digestibility and nutrient content.

Long before the development of balers, hay was stacked. The hay was first cut, then cured (dried) and windrowed and placed in buildings or in stacks or shocks in the field.

The development of mechanized stackers that compressed hay into stacks became popular again in the 1980s, when hay could be left in the field or even covered with a cotton module tarp to protect it from the weather. These stacks vary from one to six tons in size. However, baling – both small and large bales – remains more popular.

Recent developments in plastic mesh wrap (netwrap), solid, self-adhesive plastic wrap and even the use of silage bag wrap on bales has provided even more protection against weathering losses in outside storage for either round or square bales.

Hay grading systems must reflect fairly upon quality for both the seller and the buyer of the product. This is difficult with a forage product that can vary across a field and is inconsistent throughout a bale due to random distribution of leaves and stems.

Thus, evaluating hay quality requires the use of sampling points which truly represent the contents of a bale. Also, hay is often sold in lots of 25 tons or more, which may be composed of hay supplies from various fields and regions. The larger the lot, the more bale-to-bale variation.

When formulating a feeding program or ration, try to use similar bales for more precise formulation calculation. Determining quality of hay through the use of a forage nutrition analysis is the best method to work hay content into animal feed rations. This will not only determine hay quality but will indicate what type of supplements are needed to complete the feed ration.

It is true a visual estimate of hay quality can first alert you to hay that might be worth buying. Not as reliable as forage testing, a visual estimate can give you some idea of the hay’s cut, greenness, leafiness, softness, lack of foreign contaminates and odor.

Alfalfa sampling: The proof for a more marketable hay product

Hay sampling procedures and equipment
Upon any particular common lot (same cutting, variety, stage of maturity, harvested within 48 hours) of hay, a minimum of 20 core samples should be taken at random, with one core obtained per bale.

Probing near the center of one end of each bale, enter the core at right angles to the bale for full, consistently dense samples. Place each core in a freezer bag, seal, mark the bag with the sample identification (location, field, number), your name, address, phone number and e-mail and place all samples in a cool place or into the refrigerator until samples can be delivered, ground and mixed at the laboratory.

After grinding, place into a clean, dry container. Samples can be mixed and a random analysis sample taken for testing. Alfalfa hay “flakes” or hay hook samples are unacceptable for testing, as they will not provide a good, random, accurate sample.

Analytical laboratories certified by the National Hay Testing Association can test alfalfa hay for nutrient content. These laboratories can provide you with different types of analyses for determining your alfalfa quality.

Many parameters have been used to estimate hay quality. Laboratory analyses, according to the alfalfa hay standards, use crude protein concentration (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), total digestible nutrients (TDN) and relative feed value (RFV) for predicting animal performance. Grass hay is only required to use CP to designate hay standards. Low NDF and ADF values in alfalfa hay are desirable, as they are associated with increased animal intake; while high CP and TDN values indicate higher quality hay.

Even when properly sampled, some variation in laboratory results is normal. A 1- to 2-pound sample may be representing as much as a 200-ton lot from samples taken by hay brokers. If comparing results from different labs, send in samples split only after grinding. Most laboratories will return ground samples after analysis if requested, too, so a sample may be sent on for comparison, if desired.  FG

References omitted but are available upon request at

—Excerpts from New Mexico State University Extension website

Denise McWilliams, Scott Bundy, Woods Houghton, James Duffy and Gary Hathorn; New Mexico State University

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