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.


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.

Feeding From The Waste Stream


The other day I received a phone call from a dairyman who said he was attempting to “Feed from the waste stream” and he sent in two samples.   The first sample was mixed juice pressings, which consisted of a random assortment of spinach, cucumbers, ginger, carrots, apples and more, and the second sample was citrus pulp, also leftovers from juice mainly consisting of orange peels.  He tested these samples for nutritional values.  Both samples had greater than 8% crude protein and both samples were very high in nitrogen free extract meaning they were high in soluble sugars and energy as well.  Showing that these organic human food wastes do have value nutritional value as an animal feed source.  The producer went on to comment on how much his cattle loved these feeds and how affordable these by-product feeds were to him, which lead me to do some more research into the phrase he used “feeding from the waste stream”.  What I found was, the EPA encourages feeding from the waste stream and this practice could be beneficial to food and livestock producers, consumers, and the environment.  There are also added value compounds in some organic wastes which could potentially improve animal health and production. However, there are laws regulating the practice of “feeding leftovers to livestock”.

The United States alone produces 160 billion pounds of food waste per year.  These wastes can range from the leftover juice pressings mentioned above to bakery wastes to expired grocery products.  Typically, this organic waste goes one of three places, a landfill, incineration, or compost.  These options especially, the landfill option, can have detrimental impacts on the environment, therefore the Environmental Protection Agency encourages the use of organic wastes in animal production.  Below is a diagram of the Food Recovery Hierarchy which shows feeding animals as priority after feeding hungry people.


Ward Laboratories has also tested samples from Northstar Recycling a company that works to help livestock producers and food packers to recycle organic waste. I will never forget the first sample they sent to us, it was tuna by-product. We received it on a Monday and I can tell you it smelled like it had been in the mail for 3 or 4 days by the time it got to our lab.  Since then, we have received many more pleasant-smelling samples including marshmallows, assorted candies, dough waste, peanut butter, cake and more. With feed being the most expensive cost of production in the livestock industry taking advantage of these cheap waste products could improve profit margins.  Additionally, the livestock industry is constantly battling the consumer perceptions that our animals are competing with humans for grain based feeds and meat is “bad for the environment”, therefore feeding from the waste stream could improve consumer perception of the industry.

Some of the organic waste products, specifically those from leftover fruits and vegetables have value added compounds.  For example, citrus peels have essential oils which have been shown to improve immunity and have a positive effect on production.  One essential oil of interest is D-limonene.  This essential oil has been shown to improve gut microflora balance by increasing beneficial microbial populations and decreasing detrimental microbial populations, and increase feed efficiency of beef cattle and gains in swine.  Another example of value added compounds present in organic wastes is polyphenolic compounds.  These compounds occur at a higher concentration in the seeds, roots, pits, and skins of fruits and vegetables than in the edible portions utilized in human food production. Polyphenols exhibit beneficial properties such as being anti-carcinogenic, anti-pathogenic, anti-oxidative, and immune modulatory. Therefore, in feeding livestock, a producer may see improvements in gut, respiratory, and cardiovascular health in their animals.

There are regulations for feeding food wastes to livestock and the rules that apply are different depending on the source of organic food waste and the species of animal to be fed.  The Food Safety Modernization Act (FSMA) was put in place to prevent food-borne illness from occurring at the processing stage of food production. The regulations in the FSMA apply to products from human food production, this would include things like bakery waste, or juice pressings.  The regulations that apply depend on the type of facilities producing and utilizing the food waste. The other two pieces of legislature for feeding food waste to livestock are the Federal Swine Health Protecting Act (SHPA) and the Ruminant Feed Ban Rule.  Put simply, the SHPA states that food scraps containing animal products must be heat treated to kill disease causing bacteria and prevent the spread of foot and mouth disease.  The Ruminant Feed Ban prohibits the feeding of mammalian proteins back to ruminants to prevent Bovine Spongiform Encephalopathy (BSE) also known as mad cow disease.  States may also have their own rules and regulations regarding feeding food by-products to livestock.

In conclusion, there is an abundance of organic food waste products.  Their utilization as livestock feed is good for the environment, profitable for the producer, and if we tell this story can improve consumer perceptions of our industries. Some of the fruit and vegetable waste products are not only nutritionally beneficial to animals but also contain compounds which can improve production value and animal health.  If a producer is interested in “feeding from the waste stream” they should do their research, test their feeds for nutritional values to ensure they are meeting animal nutrient requirements and be aware that it is a regulated practice. Below are some additional links for further reading on this topic.

Fruit and Vegetable Wastes as Livestock Feed


Leftovers for Livestock



2017 KSU Swine Day

A couple of weeks ago I attended Swine Day for the second year in a row.  This event is a great way to remain informed on the latest in swine nutrition research. I would recommend attending for anyone involved in the swine industry.  It is also very interesting to see what the researchers are doing with all of the feed samples that go through Ward Laboratories, INC from the Kansas State University Swine Laboratory. The morning session consisted of quick 15 minute research updates on the projects in Manhattan, KS and with KSU cooperators.  Two presentations that specifically caught my attention were the feed safety presentation by Dr. Cassie Jones and the Limonene presentation by Dr. Jim Nelssen. Finally, I would be doing a disservice to the lab if I did not highlight Dr. Chad Paulk’s presentation on sampling technique from feeders.

I often field phone calls from producers wanting to test for mycotoxins. These toxins are produced from specific strains of mold under certain conditions and often appear together.  At Ward Laboratories, Inc., we only test for Aflatoxin, but always help people find a lab to test with if they would like to test other mycotoxins.  Dr. Jones’ presentation focused on what we can do with contaminated feeds specifically corn grain and how some of our common practices to reduce shrink in feed mills may be contributing to mycotoxin contamination of feeds.  Mycotoxin producing molds often thrive on broken kernels of corn.  Therefore, Dr. Jones analyzed the effect of cleaning corn or separating the broken kernels from the intact kernels on mycotoxin contamination.  She found that cleaning the corn kernels decreased aflatoxin by 26% and fumonisin by 45% in the cleanings.  However, the screenings were concentrated with aflatoxin.  Often these screenings are added back to other feeds to decrease shrinkage in the feed mill.  Thus, hitting home the point that maybe a little shrinkage could be acceptable when taking into account the potential negative effects on animal health. A summary of this research can be found on page 54 of the 2017 Swine Day publication.

In the livestock industry across all species, consumers are driving increasing demand for antibiotic free products in supermarkets.  Therefore, finding alternatives to antimicrobial products that boost performance in a comparable way is a lucrative research goal.  According to Dr. Nelssen, antibiotic alternatives represent a $20 million global industry across all species and, in swine the cost of going antibiotic free is $20.68 / pig due to decreased growth rate.  Therefore, his research compared average daily gain (ADG) in weaned pigs given feed four different feed treatments 1) Carbodox, an antibiotic fed for increased performance, 2) increased concentrations of copper and zinc, 3) the essential oil Limonene 4) a negative control diet.  Limonene is already an approved product (Victus LIV) to replace Tylosin in beef cattle.  The results of his study show that pigs supplemented with copper and zinc together or Limonene had higher ADG than the negative control diet and performed comparably with pigs supplemented with Carbodox.  A summary of this research can be found on page 31 of the 2017 Swine Day Publication.

Many producers who want to sample their feed are often unsure of how to take an accurate and representative sample.  For Hay samples I always refer them to the National Forage Testing Association guidelines, however for swine mixed feeds I have a hard time with a resource to direct them toward.  Dr. Chad Paulk’s presentation focused on quality control in feeds testing.  First, he compared probe samples to hand samples and found that the probe decreases variability among samples.  Then, Dr. Paulk compared sampling individual feeders with taking a composite sample and determined that the composite sample also decreased variability.  Additionally, the results showed that using a probe and a composite sample together reduced the number of samples needed to ensure an accurate result. Dr. Paulk’s final recommendation when taking a mixed feed sample from a feeder is:

  1. Utilize a probe
  2. Take 6 samples from 6 different feeders
  3. Combine those samples for one composite sample

A summary of this research can be found on page 55 of the 2017 Swine Day Publication.

Here just three topics covered of many in this year’s Swine Day at KSU have been highlighted.  I would encourage all involved in this ever changing industry to attend this event in the future and check out the information they have made available through the links I have included below. As for those of you looking to take a feed sample, don’t overlook the importance of an accurate representative sample.  Consider taking advantage of the technique outlined above.