Silage for Beef Cattle 2018 Conference

Last week I attended the Silage for Beef Cattle Conference in Mead, NE.  For those of you who put up corn silage, or provide advice for those who do I would highly recommend listening to the online uploads from this conference as well as looking over the proceedings. Here are 8 key concepts I took away from the conference:

  1. Processing is crucial.

Processing of the grain is very important to the digestibility and therefore, energy availability of the corn silage.  It is recommended that there should not be a single intact corn kernel in the final silage product.  To monitor this, separate the forage portion of the silage from the grain and then closely inspect the grain.  Adequate and consistent monitoring through the chopping process is key.

  1. Determining when to harvest is difficult and varies by operation.

As the plant matures fiber increases, kernel hardness increases thereby decreasing the digestibility of the forage and starch portions of the plant.  However, at a more immature stage less corn kernels are present, and the moisture of the plant is too high for ensiling.  Therefore, the recommendation was to harvest a week before or at black layer when the dry matter content of the green chop is between 33 – 38%.  However, the best practices may differ from operation to operation.

  1. Ensiling time is important.

As fermentation time increases, starch digestibility also increases.  For the fermentation to go to completion, it is recommended to ensile at least 90 days, but 120 days would be optimal.

  1. Packing is key to minimize shrink and prevent spoilage.

Delayed packing increases risk of yeast and mold spoilage.  It is also important to pack with enough weight and consistency.  Check out this packing density calculator from University of Wisconsin extension.

  1. Proper covering is also key to prevent shrink and spoilage.

O2 barrier plastics are the best option for covering, however polyethylene coverings are also an option with about a 5% difference in dry matter recovery.

  1. There are lots of ways ensiling can go wrong.

Silage contaminants can come from many different sources including soil, damages plants from hail or insects, manure, wildlife, rodents and birds.  These contaminants can include infectious microorganism such as salmonella, listeria, clostridia and toxin producing molds or undesirable fermentation by-products such as toxic amines or ammonia.

  1. Feeding spoiled corn silage at any inclusion rate is detrimental to rumen health.

Both dry matter intake and digestibility of neutral detergent fiber decrease when spoiled corn silage is included in the diet.  Additionally, when cannulated cattle were examined, the forage mat in the rumen was completely destroyed, again at any inclusion rate of spoiled corn silage.

  1. Producers can determine if they have aerobic deterioration of silage on farm.

At Ward Laboratories, Inc, I often suggest producers who are unsure of their silage to test both mold count and pH.  On farm producers can take the temperature of the center of the pile and other outer locations.  Moldy spots will be 20-30°F hotter, with up to 8 times the coliform forming units of mold than the core of the pile.

Again, this is a snapshot of the important information shared at the corn silage conference.  Check out the online uploads and consider sending your silage samples to Ward Laboratories Inc. to test for nutrient contents, pH, moisture and mold count.

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.