Feeding Wild Animals

Intermittently, I receive a phone call asking me about the interpretation of a feed analysis for a wild animal as opposed to domesticated livestock whose nutrient requirements I am more familiar with.  These phone calls usually make me do a little more research and I learn something new about animal nutrition with each inquiry.

The first time this happened, I was new to consulting here at Ward Laboratories, INC.  A producer called asking why his pheasants were suddenly losing their feathers and then dying.  The situation was dire, and his story was quite startling.  As it turned out, he was offered a very good deal on some wheat grain and had decided that would be the feed source for his pheasants.  Luckily for me the nutrient requirements for pheasants are listed in the National Research Council’s Nutrient Requirements of Poultry, so I was able to make a direct comparison between the grain he was feeding and the bird’s requirements.   It turned out that wheat grain was very high in energy, however much lower than the protein, and mineral requirements of ring neck pheasants.  The moral of that story was to have a solid understanding of the nutrient requirements of the animal you are feeding along with knowledge of the nutrients the feed is providing.

A common wild animal I get asked about is deer.  Most of these questions are about supplemental feed for deer for hunting purposes.  Deer are unique in because antler growth is very important to hunters.  For optimal antler growth deer have a very high requirement for protein.  It is recommended that a supplemental feed be greater than 16% crude protein.  Deer are also browsing animals not grazing animals meaning that they select the most nutritious portions of plants for consumption.  So, it has been shown that the total diet of a deer in the wild can be between 20-24% crude protein.  A lot of livestock producers want to utilize leftover feed supplements to feed deer on their property.  These supplements were formulated for livestock species consuming roughages not wild browse therefore, those feeds may cause health issues for deer.  Sheep and goat feed is low in copper and other important minerals and may cause a deficiency for deer.  Horse supplemental feeds are typically for active horses and therefore high in starch which may result in acidosis when consumed by a deer.

Most recently, I was asked about feeding bison.  Being unfamiliar with nutritional requirements of bison, I did a little research.  Nutrient requirements of bison have not been studied as extensively and are not as well defined as beef cattle.  Bison are more efficient utilizers of fiber than beef cattle.  They prefer to consume large amounts of grass to smaller amounts of legumes.  For the most efficient finishing production bison should be provided with a diet at about 14% crude protein and 70-90% concentrate diet so that energy does not limit growth.   Crude protein requirements for bison at other stages are not well defined but are thought to be just below those for productive beef cattle.  This is because nitrogen recycling is more prevalent in these wild ruminants than in cattle.  A management challenge bison producers face is the sensitivity of bison to cool temperatures and shorter photoperiods.  Instinctually, these animals conserve energy during the winter and consume less feed, gain less and are less productive in the winter months.  However, during summer months, bison consume more feed, gain weight at a quicker rate and are more productive.

When feeding wild animals, be sure to do some research and familiarize yourself with that animal’s nutrient requirements, as well as common feeding practices by other producers or game promoters.  Then be sure you understand the feed ingredients and how they are going to meet those nutritional requirements. Ward Laboratories Inc. can test your feeds to get an accurate report of the nutritents in the feeds you are supplementing and I am here as a consultant to help you research the nutritnet requirements of different animals.   After meticulously formulating a diet or supplement, monitor the animals you are feeding to ensure they are healthy and productive.

2018 KSU Cattlemen’s Day

The highlights of this year’s KSU Cattlemen’s Day were the tour of the Feed Intake Measurement Facility given by Dr. Bob Weaber and the necropsy demonstration given by DVM A.J. Tarpoff.  The take away I want to reiterate to any livestock producers is that a post-mortem exam is crucial in determining the cause of death to an animal and identifying how we can prevent it from happening again.

Feed is the number one input cost to raising beef cattle, and improvements in the feed conversion to product can result in increased profits for beef producers.  This makes the research on feed efficiency at KSU very important and promising to steakholders.  The difficulty with improving feed efficiency, is that is is dependent on feed intake and gain, therefore to impact efficiency or feed conversion rate, cattle need to be selected to either gain more than average while consuming the average amount of feed, consume less than average while gaining weight at an average weight, or both gain more and consume less at the same time.  Touring the Feed Intake Measurement Facility was like a trip down memory lane for me.  When I was working on my masters’ project at the US Meat Animal Research Center, my steers feed intake was monitored using the same Insentec feeding system that is featured at the KSU facility.  The Insentec system uses RFID tags to keep track of each animal each time they come to the feeder.  The feed bunk is automatically weighed before the animal begins consuming feed and then after the animal is finished.  This results in many data points for each feeding event for each animal which is then condensed into average daily feed intake over the trial period.  What sets this research facility above others is their ability to also monitor water intake as well as the ability to put cow calf pairs on the lot and monitor their feed intakes as well.

The presentation by Dr. Tarpoff, Using Postmortem Examination to Enhance Heard Health Management, is a presentation I wish all producers could have attended.   All too often I receive a phone call with someone asking to test their feed to determine what killed their cattle, without having consulted their vet first.  A necropsy is a vet bill worth paying.  Dr. Tarpoff stressed the point that even if you believe it was a death due to bloat, you must first use necropsy findings to rule out other possibilities.  He said that even if a death appears to be a bloat that could just be the feed fermenting in the animal after the animal’s systems have begun shutting down.  Using information from a post-mortem exam can aid in making the best possible production decisions to prevent death losses in the future.  It is imperative that you work with your vet when problem solving animal health issues.  At Ward Laboratories Inc.  we can test for several animal health issues in feed such as nitrates, prussic acid, high mold and aflatoxin, but often all of these come up without answers and it is too late to perform a necropsy by the time our results are sent out. Use our lab tests to confirm what your vet determines. Dr. Tarpoff recommends a necropsy on a dead animal be performed as soon as possible and at a minimum within 24 hours of death.

This year’s KSU Cattlemen’s day, did not focus on nutrition, however I believe it was very valuable for producers who attended, and I would encourage any beef producers looking to make improvements to their production to attend this event in the future.

Trade Show

Cattlemen’s Day 2018 Beef Cattle Research


Feeding the Bugs Part 2: 7 Feed Additives to Modify Rumen Metabolism

The two most common issues that occur when feeding ruminant animals are bloat and acidosis.  Bloat is the result of gases not being able to escape from the rumen.  It can occur on a forage-based diet due to rapid fermentation of soluble protein and readily available carbohydrates resulting in a frothy entrapment of rumen gases.  In the feedlots, bloat is typically a secondary symptom to rapid starch fermentation and acidosis and froth may or may not be present. Acidosis occurs on grain-based diets and is the result of decreased pH in the rumen due to rapid starch fermentation and excess lactic acid presence in the rumen. While bloat is an issue on forage diets, ruminants were adapted to consume a mostly forage diet, but it is not conducive to efficient animal production.  Therefore, cattle are often placed on high grain diets for growing and finishing at a high rate of efficiency. Along with increased production on a grain-based diet comes the increased incidence of acidosis and bloat.  Here are how 7 feed additives modify the fermentation process in the rumen to prevent bloat and acidosis.


  1. Proanthocyanidins also known as condensed tannins, are found in plants such as apples, tree bark, grapes and cranberries. These compounds when present in the rumen at 1-5ppm DM intake, can precipitate soluble protein thereby preventing the accumulation of froth decreasing the incidence of bloat. We are in the day and age where crop improvements are often from manipulation of genetic material to suppress unwanted plant characteristics such as in low lignin varieties of alfalfa and corn. Currently, the consortium for alfalfa improvement is researching the possibility of varieties expressing condensed tannins to prevent legume bloat.  This variety may be available in 8 to 10 years if the process proceeds in a similar way to the low lignin varieties.


  1. Poloxalene is a surfactant which breaks up the soluble protein froth thereby preventing pasture or legume bloat. It can top dress a ration or be offered in a molasses lick.


  1. Ionophores are a chemical compound that inhibits the growth and activity of gram-positive bacteria in the rumen. Gram-positive bacteria only have one outer cell membrane as opposed to gram negative bacteria that have two and are therefore not susceptible to the effects of ionophores on the bacterial cell. Common gram-positive bacteria in the rumen include cellulolytic bacteria and methanogens.  Therefore, the fermentation pathways in the rumen are shifted so that less methane gas is produced and more useful compounds such as volatile fatty acids, which can be utilized by the animal are produced.  Ammonia producing bacteria in the rumen also tend to be gram-positive and consequently less protein is degraded to ammonia and by-pass protein increases.  Ionophores were originally fed because they change the feed intake habits of the animal to consuming smaller amounts throughout the day which decreases acidosis occurrence.  The ultimate result of feeding ionophores on animal production is decreased feed intake, increased rate of gain and thereby improved feed efficiency.


  1. Buffers include bicarbonate, limestone and magnesium oxide. These compounds increase rumen pH, decreasing acidity. When animals are fed buffers, cellulolytic bacteria populations increase, amylolytic bacterial populations decline and the rate of starch fermentation decreases resulting in less incidence of acidosis.


  1. Direct Fed Microbials (DFM) are just as they sound, the purposeful feeding of specific microbial species to alter ruminal microbe populations. When feeding DFM the bacterial population is meant to shift from lactic acid producing bacteria to lactic acid using bacteria thereby preventing acidosis. With this feed additive results vary, and they do not always exhibit an impact on acidosis.


  1. Enzymes that are meant to break down fibers are sometimes fed to increase forage utilization in the rumen.


  1. Essential Oils are naturally occurring plant secondary metabolites. They are not well understood, and research results are varying. They are currently thought to have the potential to alter rumen fermentation pathways, but the mechanism is not known.


Although the above feed additives can help prevent bloat and acidosis, they can not replace a properly formulated step-up ration and diet or production practices such as backgrounding.  One of the best ways to prevent these aliments is to test feed ingredients and formulate a diet plan that moves animals from a low energy forage-based diet to a high energy high-grain diet gradually.  This allows those intermediate acid utilizing bacteria with a slower turn over rate to catch up with the diet and reduce the chances of acidosis.

Feeding the Bugs Part 1: Exploring the Interactions of Rumen Microbes

Soil microbes are all the buzz these days, but what about rumen microbes?  Currently, it is very common to go to a ruminant nutrition meeting and hear about feeding the microbes first.  This is especially the case with the NRC Nutrient Requirements of Beef using the microbial protein and bypass protein system.  There are four groups of microbes that can be found in the largest compartment of the four-chambered stomach, the rumen.  These groups are bacteria, protozoa, fungi, and archaea. These microbes make up a diverse microbial community that behaves synergistically to prevent feedback end-products of fermentation, and to ensure rapid fermentation and digestion of feed.  Understanding how these microbes perform and interact in the rumen can help producers to understand why certain feeds have the effects that they do in the rumen, for example why acidosis or bloat is more likely to occur on certain diets and how a step-up ration can help prevent these digestive issues.

Bacteria are small in size and replicate quickly making them the most populous microbe in the rumen at about 100,000,000,000 cells / mL of rumen fluid.  Therefore, they play an important role in ruminal fermentation.

Cellulolytic bacteria are important to the breakdown of the fibrous structure of the plant material.  They adhere to forages to avoid predation by other microbes and utilize cellulase, a membrane bound enzyme, to breakdown plant fibers.  Populations of cellulolytic bacteria are highly affected by rumen pH.  On high forage diets, lots of ruminating is needed to breakdown the feed into small particle sizes for fermentation resulting in lots of buffering saliva present in the rumen allowing cellulolytic bacteria to thrive.  On high grain diets, cellulolytic populations decline as pH decreases and the rumen becomes more acidic. Important species of cellulolytic bacteria include Fibrobacter succinogenes, Ruminococcus albus, and Ruminoccuc flavefaciens.

Hemicellulolytic bacteria degrade hemicellulose into sugars, which can be used as a substrate of fermentation by other microbes in the rumen.  Most Ruminococcus bacteria fall into this category.

Amylolytic bacteria can utilize ammonia as a nitrogen source, and amylase, a secreted enzyme, to breakdown starches.  Like cellulolytic bacteria, their populations are also regulated by pH.  Inversely to cellulolytic bacteria, amylolytic bacteria are more prevalent on a high grain diet and decline with increasing pH and rumen buffers.  Amylolytic bacteria produce lactic acid which sometimes results in lactic acidosis.  Streptococcus bovis is an important species of amylolytic bacteria.

Intermediate acid utilizing bacteria are also very important to rumen fermentation.  These species utilize lactic acid, and succinyl acid as a fermentation substrate.  Intermediate acid utilizing bacteria are key to adaptation to high grain diets, however their reproductive rate is significantly slower than other bacteria, making production management such as backgrounding or implementing a step-up ration that much more important in the prevention of acidosis.  Important species of intermediate acid utilizing bacteria are Megasphaera elsdenii and Selenomonas ruminantium.

Proteolytic bacteria are very important in the rumen as they breakdown protein into peptides, amino acids and ammonia for growth by other rumen microbes. They also produce branched chain fatty acids which stimulate the growth of cellulolytic bacteria.  Some important proteolytic species are Peptostreptococcus and Clostridia.

Ureolytic bacteria only make up 5% of the rumen microbial population and are associated with the rumen wall.  These bacteria can break urea into ammonia and carbon dioxide allowing other microbes to utilize the ammonia as a nitrogen source.

Lipolytic bacteria use both secreted and membrane bound lipases to breakdown fat.

Protozoa make up a smaller proportion of the rumen microbe population than bacteria, but 50% of the microbial mass due to their larger size.  Protozoa cannot utilize non-protein nitrogen in the form of urea or ammonia.  They also predate smaller microbes such as the bacteria discussed above.  Most protozoa digest non-structural carbohydrates such as sugars and starches.  They play a role in acidosis prevention by sequestering some starch away from amylolytic bacteria. There are two classes of protozoa associated with fiber digestion.

Holotrichs have a long replication time, and are very sensitive to low pH, acidic environments. Therefore, exist mainly on a high forage diet and are not present in animals fed a high grain diet.

Entodiniomorphs have a short replication time and a greater population than Holotrichs.  They are also more tolerant of low pH environments. Therefore, Entodiniomorphs are present in the rumen on a high grain diet but are less prevalent.

Fungi have very low populations in the rumen but are very important to fiber digestion.  Fungi utilize their hyphae to physically separate strands of fiber.  Picture the stem of a mushroom as the hyphae and the log it is growing out of as the cellulose bundle it is breaking down.  Fungi also produce cellulase, an enzyme for breaking down the fibrous portion of the plant.

Archaea are not very populous in the rumen, but their impact on the efficiency of fermentation is very important. Archaea are the major methanogen producers in the rumen.  They utilize hydrogen produced by cellulolytic bacteria to produce methane gas, which is eructated by the animal.  This eructation, is considered an air pollutant by staunch environmentalists and a source of decreased production efficiency by producers.  The ionophore Monensin can be utilized to decrease methanogen numbers.  Important species of archaea are Methanobrevibacter and Methanomicrobium.

The four groups of microbes present in the rumen, bacteria, protozoa, fungi and archaea, play a major role in how ruminants utilize various feeds especially forages and high starch concentrate.  An understanding of microbial roles and interactions in the rumen can help a producer understand the importance of feed testing when formulating a new ration, changing the ruminant’s diet from forage-based to grain-based, and preventing acidosis or bloat.

Get the Scoop on Using Your Poop

Phewy! Smell that? From an early age, we are often told the old phrase “That’s the smell of money!” Although this phrase is often used to indicate cattle profits, the manure in those pens also holds a wealth of resources that can help enrich and strengthen your soil. Once used routinely in integrated farming systems, manure plays a critical role in returning nutrients to the soil. With the shift from integrated livestock and row crop farms to separated specialized operations, the natural cycle of many nutrients has been disrupted. This separation of practices has led to an overabundance of manure in some areas and a lack of nutrients in others, causing a shift to synthetic fertilizer use. So, what does manure do to our soil?

Manure is an important source of raw or partly decomposed organic matter. The nutrients in manure can vary depending on the animal type, health, age, feed ration, bedding and water content. In addition, the various management practices associated with handling manure, manure storage, duration of storage, application amount, application technique and weather can all dramatically alter the nutrient content in manure and thus the amount of nutrients available in the soil and for future crop use. Understanding and applying the correct amount of manure to your fields can be accomplished by testing your manure prior to application. You would be surprised how much it can vary! The table below highlights the difference in nutrient levels found in beef cattle manure that we have processed at the lab in the past five years. Want to see how swine, poultry, dairy cattle, or compost fared? You can check it out here.

Beef Manure


First, let’s set the stage. Before manure ever touches the soil, soil fauna (e.g. ants, earthworms, arthropods etc.) and microbial populations (e.g. bacteria, fungi, viruses) naturally exist in your soil. These populations, or communities, are incredibly diverse and have varying community structures that reflect your soil quality, or “soil health”. The majority of the microbial populations exist within the top few inches of your soil, clustered around the root structures of plants, known as the rhizosphere. Soil microbial activity is responsible for the main decomposition of all litter inputs into the soil. Larger fauna in the soil are important for the preliminary break down of residue into small pieces, creating greater surface area for microbial activity. They also move fragments of litter throughout the soil structure, exposing the litter to larger microbial communities, which provides a natural incorporation without resorting to mechanical methods. When food is scarce (e.g. winter months when no living plant is present), microbes have the natural ability to enter a low energy requiring comatose-like state to preserve their nutrient supply until food is readily available again.

Initial introduction of manure is a feeding frenzy for soil microbes. Manure not only contains a large amount of macro and micro soil nutrients but also inoculates the soil with microorganisms excreted by livestock. The nutrients in manure, although processed by the host, require a suite of soil microbe activity to alter the chemical structure of nutrients to make them available for microbe and plant use. Much like hungry teenagers at a buffet, microbes attack the most easily accessible forms of food first: sugars, starches and other soluble nutrients. This initial process is often rapid. Once these resources have been used, the breakdown of more complex soil compounds begins and is a slower process like preparing a box of mac and cheese. It takes time and a little bit of effort. This process includes the breakdown of cellulose and hemicellulose, both found in plant tissues. Lastly, complex compounds, such as tannins and lignins (found predominantly in woody plant species) are broken down. This process occurs over a long period of time and with a lot of help. It’s almost like preparing a Thanksgiving feast. This process requires the specific activity of select microbes (e.g. White Rot) to breakdown these compounds.

Microbes are very similar to people in the way they act. Although the main end product of aerobic (or oxygen loving) microbial activity is to release carbon dioxide (CO2) and water, microbes require nutrients to support growth, maintenance and reproduction. Thus, microbes make a living by harvesting carbon and other nutrients from the soil organic matter. Microbes are responsible for converting many minerals from organic to inorganic forms (often referred to as “mineralization”) that are easy to take up for both the microbe and plants. For instance, microbes need N to meet many microbial needs (e.g. protein building). If there is an abundance of N in the organic matter, extra microbial processed N, in the form of ammonium-N (NH4+-N), is released into the soil environment. Due to the close proximity of microbial communities and plant roots, the released, easily available N is taken up by the plant. Increases in nutrient sources, such as the addition of manure, stimulates microbial growth and reproduction, resulting in a larger, more active microbial community. Larger populations lead to greater microbial turnover, in which the death of the microbe releases nutrients gathered during its lifetime and can now be utilized by plants.

In addition to the minerals microbes liberate for plant use, manure and microbes can also help build your soil structure. Increased presence of organic inputs promotes microbial activity and decomposition. During this process, polysaccharides are produced as a by-product and help bind macroaggregates together in the soil. Polysaccharides  are sticky, glue-like substances that form bridge-like structures between aggregates and are resistant to degradation in the soil. The accumulation of this activity creates a snowball effect in the soil. Stabilized aggregates create tunnels that increase soil porosity, soil water holding capacity, nutrient cycling and nutrient availability to microbial communities. In turn, these characteristics support an improved soil drainage system, a decrease in bulk density and compaction, and a decrease in soil crusting and erosion.

The rate at which decomposition occurs in the soil is dependent on the quality and composition of the manure, the microbial community structure, weather and time. This rate causes manure to act like a slow release fertilizer, ensuring all the nutrients are not lost during initial application or shortly after. A manure analysis report often provides a “First Year Availability” value to help you understand and apply the correct quantity of nutrients needed for your crop. These manure mineralization approximated values are calculated based on similar mineralization rates found in research for each manure type. If you like to apply manure in the fall but are concerned about potentially losing nutrients due to soil moisture and microbial activity, consider incorporating cover crops into your rotation to help cycle nutrients in the soil. As they breakdown in the winter and spring, they will release the nutrients consumed from your manure application while supporting a healthy, thriving soil microbial community.

Applying manure to your soil can be an efficient way of stimulating an active, healthy microbial community while providing nutrients to your crop. Manure quality is dependent on various factors that contribute to the dominate microbe community and nutrient forms. Be sure to properly analyze your manure before you apply to ensure you are getting the most out of your valuable resource. Understanding and properly applying manure could help save fertilizer costs in the future while boosting your soil microbial community resiliency and soil health. So go ahead and take a deep breath. That’s the smell of money.

Drought Planning: 4 Ways to Stockpile Forages

The state of Nebraska is in the center of the High Plains Region of the United States.  The states that make up this region are Nebraska, Kansas, Colorado, Wyoming, and the Dakotas.  I checked the current drought monitor and found that southern Nebraska and southern Wyoming are abnormally dry, and Kansas, Colorado and the Dakotas are experiencing various levels of drought.  The current outlook through April is promising for the Dakotas, but dry for the rest of the region.  Precipitation from the Canadian border is predicted to remove the drought from North and South Dakota. The Dakotas are projected to experience a normal spring season.  As for the rest of the region, southern Nebraska, southern Wyoming, Colorado and Kansas, drought is likely to persist through April 1st.  Soil moisture levels on April 1st will have a great impact on the availability of forages throughout the region during the summer months. When planning for drought conditions, which are likely to result in decreased forage production, especially on dry pastures and rangeland, most producers’ strategy is to decrease animal numbers and stockpile forages.  Here are four ways to stockpile forages for livestock during drought conditions:

  1. Buy Hay

Buying hay is the first thing that usually comes to mind when people think of stockpiling forages.  During a drought, it is likely that local hay may be of lower quality, therefore it is important to test the protein and energy values (I reccomend a minimum of an NIR scan or the F-3 test at Ward Laboratories, Inc.) before feeding to ensure the forage will meet the animals’ nutritional needs. Hay nutrient values may change during transportation, so if hay is being shipped from another region be sure to test after receiving the lot and before balancing a ration to feed livestock.  Having extra stockpiles of hay for drought or emergency feeding is never a bad thing, however buying hay during a drought can be expensive due to less availability, higher demand, and transport costs.  Therefore, it would be beneficial to maintain supplies of hay during periods of plentiful forage conditions. In other words, it is most economical to buy hay in excess when it is low in demand and forages are in good supply and save some back as emergency or drought feed.  If you are located in Nebraska and are looking to buy hay check out the Nebraska State Hay Hotline.

  1. Graze Crop Residues

If your operation is located near farmland, consider working with your neighbors to allow your livestock to graze their crop residues.  Cattle can graze preferentially to take advantage of high protein, low fiber portions of the plants left standing in the field.  If you reside in southern Nebraska or Kansas, corn or wheat residues are good alternative forages especially when fed with energy supplements.  When grazing crop residues, be cautious and remember to test for nitrates before letting animals out onto the filed.  This option for stockpiling forages is cost effective, however labor intensive and may require cooperation with neighbors.  If you live in Nebraska check out the crop residue exchange to find farmers willing to let you take advantage of this great forage source.

  1. Graze Cover Crops

Adding cover crops to your own cropping rotation can be another great way to stockpile forages.  Cover crops allow you to extend the grazing season into the fall.  Preferential grazing increases the animals nutritional plane and therefore performance may also increase.  If you are lucky enough to get some moisture after grazing, cover crops may produce regrowth and animals may be able to graze those areas again.  There are also many benefits to adding cover crops into a cropping rotation for the soil. For more information on that read guest author, Emily Shafto’s Cattle and Crops: Completing the Nutrient Cycle. Planting a diverse cover crop mixture can ensure that if one species in the mix fails others will thrive, diversity can prevent disaster. Cover crops are cost effective as a source of forage, especially in a drought.  They are however, more labor intensive and if they are high in nitrates, prussic acid or sulfur, they may detrimentally affect animal health and mortality.

  1. Rent Additional Grazing Lands

If you are not located in an area where cropping agriculture is prevalent, and you rely on rangelands to provide forage for the summer grazing months.  Renting additional grazing lands may not be very cost effective immediately, but in the long run it will take some of the pressure off the lands typically grazed and allow them to rest and rejuvenate to provide forage for the next grazing season.  Renting additional grazing lands may be a hit to the pocketbook during that drought season, but it will prevent over-grazing, which is a necessity when practicing good land stewardship.


Stockpiling forages, using one or more of the strategies above, can help prevent a disastrous drought situation.  Always monitor the precipitation and temperature conditions so that you can do your best planning for the future.  Always look for creative ways to fill gaps in feed availability.  A feed or NIR test from WARD Laboratories, INC can aid in decision making when it comes to feeding alternate forages. When buying hay, test nutritional values after shipment and before feeding for accurate results.  When grazing corn stalks, oat stubble or wheat stubble check for nitrates before letting animals out in the field.  And revisit my blog 6 Cautions When Grazing Cover Crops to ensure you are feeding a safe forage when grazing cover crops.  For more information on drought planning visit the National Drought Mitigation Center.


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.