5 Steps for Proper Hay Sampling

With the first cutting of hay coming off fields in southern states, I am reminded that proper hay sampling procedures are a must.  Today I was brought a sample from a single bale of mixed hay and asked to sort the alfalfa from the grass hay and use those as individual, separate samples.  I was not the only one whose first reaction was, are they planning on sorting it out every time they feed?  (Of course not!) For someone who is very passionate about providing producers with accurate, precise and above all else useful results, this request was difficult to stomach.  No matter what species of animal is being fed, lab results are a useless waste of producer time and lab time if they are not representative of the entire pile of feed or stack of hay.  So, when sampling hay and other forages the goal is to provide WARD Laboratories Inc. with a representative sample.  Here are 5 steps to obtain a representative hay sample:

  1. Define ‘lots’ of feed.

A lot can be one field of the same or a mixed species which has been harvested and bales in one consecutive time frame.  For example, if I had three fields two alfalfa and one mixed alfalfa and grass.  I harvested and baled one alfalfa field, then the mixed field and then a few weeks later finally harvested and baled the second alfalfa field.  I would define 3 separate lots based on species and time of harvesting and baling.

  1. Use a hay probe.

Using a hay probe will ensure samples representative of each bale.  The probe can cut through the side of the bale and take sample from deeper within the bale than a hand grab can.  Additionally, a hay probe does not discriminate against delicate leafy material the way fingers do.  A sample taken with a hand grab will test falsely low in protein and energy as the leafy material, which is high in protein and energy, slips through fingers.

  1. Take a minimum of 20 probes per lot.

If the lot has less than 20 bales, then take one probe per bale.  If more than 20 bales are in a lot take a minimum of 20 samples to represent that lot properly.  The National Forage Testing Association has done research to prove this number of probe samples decreases likelihood of a non-representative sample. When choosing bales to probe it is also important to not leave out ‘bad looking bales’ or intentionally include ‘good looking bales’.  Sample as randomly as possible.  The best possible thing to do is come up with a system to determine which bales to sample and follow it each time you sample a new or different lot.

  1. Split the sample using the cone and quarter method.

Once 20 cored samples are obtained, they will not all fit in a quart sized Ziploc bag. Therefore, the sample must be mixed and split until the sample is small enough to fit in the bag. On a tarp, large newspaper or other clean surface, mix the cores then pile them up into a cone like shape. Divide the cone into 4 quarters discarding two quarters diagonal to each other and repeating the process with the remaining two quarters.  Continue the process until each quarter can fill a quart sized Ziploc bag.  Then send one of those quarters to Ward Laboratories Inc. and save another quarter in a cool dry place.  The saved sample may come in handy if the original gets lost in the mail, or a resample is needed for some reason.

  1. Send the sample to Ward Laboratories Inc.

When placing the sample in an envelope or mailer, be sure to include your name, address, phone number.  Write the test on the sample bag or call into be sure you receive the information you want on your report.  Remember, if a result looks suspicious, Ward Laboratories Inc. will rerun tests to ensure accuracy upon request.

 

For further information on representative hay testing or to become a certified sampler check out foragetesting.org.  Here is a infomative video by Dr. Mary Drewnoski, currently a Beef Systems Specialist at the University of Nebraska-Lincoln:

 

 

Forage Creativity: Soy-Corn Silage

Here at Ward Laboratories Inc., we often encourage producers to be creative and try newapproaches to agricultural production.  A couple of weeks ago at the American Society of Animal Science Midwest meeting in Omaha, I listened to a talk about getting more creative with corn silage: “Production of High-Quality Forage through Unique Forage Blends” presented by Dr. Ishwary Acharya.  Ward Laboratories Inc. tested 1,451 corn silage samples and 2,197 total silage samples of all types in 2016.  So, I have seen the range and variation in the nutrient quality of silages used in the area.  Dr. Acharya’s research focused on making the best possible silage for a dairy operation, as he stated in his talk, “the ultimate measure of forage quality is milk production”.  Being in central Nebraska, I think his research could not only increase the nutritional content of the silages produced, but also the value of grazing the cornstalks by a beef enterprise after harvest.

The idea behind Dr. Acharya’s presentation was to double crop corn and vining soybeans to produce high protein low fiber silage without sacrificing yield.  First, to produce the best possible corn silage, the crop was chopped higher than producers typically chop corn silage.  This resulted in less stock and more leaves, husks, and cob in the silage.  Therefore, yield was compromised for higher protein and lower fiber concentrations.  The second part of the presentation explained that to overcome the sacrifice of yield, vining soybeans could be intercropped with the corn.  Therefore, when chopping for silage at a higher level, the soybean plant material made up for the loss of stocks in the yield.  In this study, the resulting silage had increase yield, forage quality, and protein compared with typical corn silage.  Dr. Acharya interseeded the vining soybean at various rates and determined that the optimal rate was somewhere between 67% corn 33% soybeans and a 50:50 mix.  The study also looked at the optimal time for fermentation based on pH and presence of volatile compounds that have affect on rumen function and animal performance.  At 60 days of fermentation Dr. Acharya determined that fermentation had not gone to completion and the silage should be ensiled for at least a 90-day period.  This finding agrees with other literature I have read on the topic.

Dr. Acharya’s idea of double cropping to create a high-quality forage source for dairy cattle could also be of benefit to beef cow calf pairs grazing the remaining corn stalks.  If soybeans were intercropped, I would predict that there would be some beans and vining materials left in the field which would be higher in protein and lower in fiber than the corn stalks alone.  Of course, I would advocate that producers test both their silage and try to get a representative idea of what has been left on their field to provide necessary supplementation.  For the silage, I would recommend testing crude protein, acid detergent fiber to predict energy values and neutral detergent fiber to predict dry matter intakes at a minimum noting that the sample would need to be ran as a wet chemistry feed test and that the addition of soybean to the silage would not allow for a reliable and accurate NIR scan.  For the grazing stocks and soybeans, I would run the same test to get an idea if protein or energy supplementation are necessary.  I would also caution that soybeans do contain urease and we typically do not graze cattle on soybeans fields as they risk urease toxicity if they have recently consumed non-protein nitrogen (NPN), therefore when considering supplementation strategies for cattle grazing a field of cornstalks intercropped with vining soybeans, lick tubs or mineral mixes with urea could not be utilized.

As, with any novel feed, always monitor animal body condition, production and health to ensure it is providing the nutrients required.  Don’t be afraid to try something new.  It might be of benefit to your operation weather it is vining soybean corn silage or grazing cover crops or feeding from the waste stream, feed testing and good ration and diet formulation can lead to success of a livestock operation.

Quarrels About Quality: 14 Sources of Variation in Forage and Hay Testing

When it comes to hay testing, producers commonly grumble about the variation in Relative Feed Value (RFV) and protein content, based on their observations and what the lab reported.

Producers often have these concerns, because the RFV determines the price of a forage and how much customers are willing to pay.  An underestimated RFV can result in decreased profit for forage producers.  A couple weeks ago, I attended the NIRS Consortium annual meeting where Rocky Lemus gave a very informative talk about the importance of proper sampling, which addressed the producer concerns I often hear.  Variation in forage test results can come from in the field, storage, sampling, and in the lab. Here are 14 common sources of variation within a forage sample:

 

  1. The leaf : stem ratio, forages with a higher leaf : stem ratio are typically higher in protein and RFV. This is because the leafy portion of the plant contains more protein than the stems. Additionally, the stems are a structural part of the plant containing higher amounts of fiber.  Acid detergent fiber (ADF) and neutral detergent fiber (NDF) are used to calculate RFV therefore, forages and hays with more leaves and less stems are lower in ADF and NDF and higher in RFV.

 

  1. The weed content of a forage can affect the RFV. Weeds are high fiber plants, so the more weeds contaminating the forage or hay the lower the RFV. Weeds also tend to be lower in protein, thereby also affecting the nutritional content of the forage.

 

  1. Baling conditions can also affect the RFV of a hay. If hay is baled under moist conditions or after having been rained on, the water-soluble sugars have been removed from and plant. The percent of ADF and NDF are increased due to the absence of sugars.  The result is a RFV and lower energy forage.

 

  1. Species of forage also affects RFV. This is not news to hay producers or livestock feeders.  It is well understood that legume forages such as alfalfa and clover are typically higher protein and higher RFV, than grasses.  This is a result of the leaf : stem ratios.

 

  1. The maturity of a plant can also affect the feed value. Older more mature plants are more fibrous, and they typically have a lower RFV than a lush growing forage.                     plant maturity

 

  1. Fertilization can result in higher protein in a forage and lower ADF and NDF. Fertilization management may help produce high quality forages. Be cautious to avoid creating a high nitrate forage by applying too much fertilizer.

 

  1. Proper storage of a baled hay is very important. Reduce ground contact as this will result in accumulation of moisture from the ground and a decreased RFV. Protect your baled hay from the elements to avoid losses of soluble sugars and protein.  Wind and rain alike can remove the leafy portion of the plant thereby decreasing protein and RFV.

 

  1. Division of forages into separate lots can affect the accuracy and representation of a forage sample. Lots should be defined by both species and field from which it was baled. For example:  If there are three fields two alfalfa and one grass, the lots need to be separated by not only species, but also field as one location may have a differing quality that the other based on management, precipitation differences, or topographical differences.  Therefore, I would send three separate hay samples to Ward Laboratories, INC. for NIR testing.

 

  1. Proper sampling procedure is very important. Using a hay probe is the key to ensuring a representative sample. Hay probes can accurately represent the leaf : stem ratio, whereas using a hand grab can result in the leafy portions falling through fingers and obtaining an overrepresentation of stems and a lower RFV.  Additionally, with a hand grab only one layer of the bale can be grabbed and to ensure a representative sample it is important to sample several inches inside the bale.  For more guidelines and to become a certified hay tester visit the National Forage Testing Association.

 

  1. The number of cores taken is another source of variation when testing. The recommendation is to combine 20 randomly selected cores. The difference between taking 20 cores and 10 cores can cause variation in crude protein by up to 5%, meaning taking only 10 cores could either over estimate nutrient values or under estimate them.

 

  1. It is very important to ensure proper treatment of samples in delivery. If the sample is hay, it is typically dry enough to not have cause for concern. If it is a fresh forage clipping, check the moisture, if it is very damp rotting can occur on its way to the lab in just a few days stuffed in a box with other samples or envelopes.  Of course, the portion of the plant that rots first is the leaves, so the RFV decreases when this happens on the way to the lab.

 

  1. Splitting in the lab can also affect RFV. Ward Laboratories, INC. uses the cone and quarter method on all forage samples that come in the lab. It is very important that when the lab splits the sample for the portion to be tested it represents the sub sample given to us.  Sometimes, it is requested to send the sample on to other labs, when this happens, the sample is split into two – three sub samples and the NIR scans are checked to ensure the sub samples nutritional values repeat.  This way we can keep some sample in our lab in case further testing is requested and it is a good way to check that our sub-sampling procedure is accurate.                                                                                                                                                                                                                                                      img_2506-e1517945202593.jpg

 

  1. Drying of the sample in the lab can result in heat damage to the sample therefore again decreasing RFV. Ward Laboratories, INC dries samples in an oven at 64°C before grinding, the typical dry matter after grinding is between 95-97% dry matter. Other labs use microwave ovens for faster drying time, however using a microwave does result in higher incidence of heat damage to samples.

 

  1. Grinding of the sample can also make a difference as to how it scans NIR. Ward Laboratories, Inc. grinds samples through a 1mm screen. More coarse grinding can cause inaccurate results on the NIR instrument.

 

When questioning results of a forage or hay sample, consider all the sources of variation that went into that sample. Sampling plants is tricky business as it is a variable material.  Always do your best to take a representative sample.  Call the lab if you have questions or concerns before taking your sample or interpreting your results.