Carbohydrates and Forage Quality

The function of carbohydrates in any animal’s diet is to provide energy.  Some carbohydrates are more easily digestible and provide energy to the animal, or in the case of the beef cattle, to the rumen microbes more rapidly.  These carbohydrates are Non-Fiber Carbohydrates (NFC). Examples of NFC are starch and sugars, such as glucose and fructose, which are measured at Ward Laboratories Inc. as Total Sugars Invert (TSI).  Starch is also analyzed at Ward Laboratories Inc.  by breaking down the polysaccharide into simple sugars.  An example of a high starch forage is good quality corn silage.  An example of a high sugar forage is high quality alfalfa hay or haylage.

Samples dissolving into buffer on the hot plate with stir bars for starch analysis

 

 

 

Fibrous carbohydrates such as cellulose, hemicellulose and lignin are slowly digested.  In ruminant nutrition the two fiber types we typically use in formulation of feed rations and in evaluation of forage quality are Neutral Detergent Fiber (NDF) and Acid Detergent Fiber (ADF).  The indigestible and slowly digestible portion of feed is represented by NDF which contains cellulose, hemicellulose, and lignin.  The least digestible portion of feed is represented by ADF and contains cellulose and lignin but not hemicellulose.  Therefore, ADF is always less than NDF when represented as a percentage of the feed or forage being analyzed.

img_0943.jpg
ADF and NDF are measured using Ankom bag technology.

The Neutral Detergent Fiber of a feed makes up the floating mat of feed in the rumen.  This floating mat physically stimulates the animal’s digestive processes, specifically rumination.  A high NDF feed typically forms a mat that exists for a longer period of time in the rumen resulting in the animal feeling full longer due to the physical gut fill and consequently consuming less feed.  In summary, high NDF feeds, typically low-quality forages, are predictive of low dry matter intake, while low NDF feeds are predictive of a higher dry matter intake.

Acid Detergent Fiber is used in predictive equations to calculate the energy content of the feed.  Total Digestible Nutrients (TDN), Net Energy of Gain (NEg) and Net Energy of Maintenance (NEm) can all be calculated using the ADF value.  Feeds with a higher percentage of ADF have a lower percentage of the high energy sugars and starches.  Therefore, high ADF feeds and forages have lower energy values and low ADF feeds and forages have high energy values.

At Ward Laboratories Inc. I receive phone calls inquiring about why certain forage reports have higher Relative Feed Values (RFV) or Relative Forage Qualities (RFQ) than others or why those two index values do not match for the same feed.

Relative Feed Value was created to quickly compare the quality of legume hays such as alfalfa or clover. We often apply this index to other forages, or feeds forgetting the original purpose and loosing the understanding that it was not originally meant to be applied to grass hays, corn stalks and especially not corn grains and other non-forage feeds.  Therefore, non-legume forages typically have lower than expected RFVs and animals consuming this hay perform better than the index value would predict.

Relative Forage Quality was created to be inclusive of most forages and is a quick way to fairly compare one forage to another weather it is a grass hay or legume.  The values for RFV and RFQ on the same feed often are separated by as much as 20 points because RFV uses ADF and NDF to predict digestible dry matter and dry matter intake while RFQ uses crude protein, fat, NDF, NDF digestibility among other factors to predict dry matter intake and total digestible nutrients.  South Dakota State University Extension has put together a great resource for better understanding of RFV and RFQ.  Below are the simplified equations for each index:

RFV = Digestible Dry Matter × Dry Matter Intake / 1.29

RFQ=Dry Matter Intake × Total Digestible Nutrients /1.23

    In conclusion, carbohydrates provide energy to the beef cow and support the growth and role rumen microbes play in ruminant digestion.  The higher percentage of the forage or hay is made up of fibrous fractions, such as ADF and NDF, the less NFC are available to rapidly provide energy.  Therefore, as ADF and NDF increase the forage quality decreases due to lower energy values and declining feed intake.  So, when feeding low quality forages such as old cane hay or corn stalks it is important to provide energy supplements in the form of beet pulp, distillers grains, corn grains or molasses based liquid supplements for example. However, on low ADF and NDF, high quality forages little to no supplementation is needed to support animal maintence and production performance.

April Snow Showers Bring Stress and Scours

This spring we have had some very untimely snow storms.  Some have even been historical, such as the blizzard that hit most of the midwest including Minneapolis as I was traveling to the Montana Nutrition Conference and Livestock Forum.  Unfortunately, I was not able to attend the conference as my airplane was diverted and the rebooked flights canceled, TWICE! So now here I am some how stuck over a thousand miles from my destination (Bozeman, MT) in the upper penensula of Michigan.  However, this was a minor inconvenience for me compared with the obstacles cattle producers face this season.  Through social media I have read countless stories about ranchers doing all they could to save calves and help cows in these snowy, windy, unseasonably cold conditions.  I have read about ranchers who were out rounding up newborn calves that were struggling as the storm began to roll in.  Some of those producers wrote of feelings of sadness and failure as they lost visibility and it became unsafe for them to be out in their pastures attending to their livestock. Other farmers, were able to get their calves in a hoop house shelter or barn to ride out the storm.

calvesinbarn2
Joeseph Skroch’s calves in a barn riding out the blizzard in central Minnesota.

While the storm has past, producers are not in the clear just yet.  Weather events such as this blizzard put extra stress on cattle.  The increased levels of cortisol in the animal’s system suppresses the immune system leaving them more susceptible to other infectious agents.

In mature cattle, the suppressed immune system is often taken advantage of by infectious agents resulting in a respiratory disease.  Bovine Respiratory Disease Complex (BRDC) can be caused by viral infectious agents (Bovine Respiratory Syncytial Virus (BRSV), Parainfluenza 3 (PI3), Infectious Bovine Rhinotracheitis (IBR)), bacterial agents (Pasteurella multocida, Mannheimia haemolytica, Histophilus somni, Mycoplasma bovis) or a combination of any of the above.  

In calves, this increased level of stress and suppressed immune system culminates as diarrhea, or calf scours.  With the storm, chances of calf scours increases if the dam is shortchanged nutritionally resulting in poor quality milk for the calf.   If the dam is low on protien and energy, she cannot produce milk containing the nessicary antibodies to protect the calf.  Therefore, especially after this storm event it is important to ensure a well formulated diet for the cow.  Opportunistic infectious agents can also play a role in calf scours and can be bacterial (Escherichia coli, Salmonella, Clostridia perfringens), viral (Rotavirus, Coronavirus, Bovine Viral Diarrhea (BVD), IBR) or parasitic (Cryptosporidium, Coccidia).

When cattle are already under extra stress due to the weather, it is important to not add any additional stress through poor nutrition.  Be sure to formulate precise and accurate diets for both the cow and calf through feed testing and consulting at Ward Laboratories Inc.  A good ration to avoid nutritional stress will provide ample protein, and energy to meet physiological requirements of the animal.  It is also important to provide minerals in the diet to support the immune system. When the immune system is supressed from stress due to the changing weather, absorption of minerals vital to immune function such as magnesium, selenium, copper and zinc are supressed.  A combination of stress and imporper nutirition can render a good vaccine schedule useless.  In addition to providing a high quality diet, avoid feeding questionable feeds containing mold or aflatoxin as these agents may not directly cause illness or death, they can contribute to the suppression of the immune system resulting in respiratory symptoms and reduced reproductive productivity.  While no one can truly be prepared for all adverse weather events.  Producers can always utilize all their knowledge and resources to move forward after an event such as this spring’s blizzard and snowstorms.  Now hopefully I will have made it back to Kearney, NE by the time you are reading this post and we are done with all of this cold weather and on to summer forage production!

 

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.

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.

file-1
Trade Show

Cattlemen’s Day 2018 Beef Cattle Research

 

Integrated Systems Agriculture: 4 Benefits of Grazing Cover Crops to Beef Producers

Intensive, specialized crop production has several widely agreed upon downfalls.  These specialized systems tend to have stationary yields with expensive pesticide and herbicide inputs all while profitability is widely dependent on a global market over which we have little control.  Dependence on these practices  leads to higher resistance among  insects  and weeds, reliance on fertilizers due to nutrient depletion  in the soil,  soil erosion and contamination of waterways due to run off, and improper soil management practices. Soil scientists and agronomists agree that the addition of cover crops to a cropping rotation can improve soil quality and health through decreased erosion, increased microbial activity, increased carbon sequestration, more soil aggregates, and increased conservation of moisture in the soil, all due to a more extensive rooting system and ground residue protecting the soil for more months out of the year.  The addition of livestock, most commonly beef cattle, to this rotational cropping system decreases the need for herbicides and fertilizers, as they help deplete the weed seed bank and their manure contains many nutrients vital to plant nutrition and soil health. Guest author, Emily Shafto, covered the benefits to the soil extensively in her blog Cattle and Crops: Completing the Nutrient Cycle.  Here are four benefits of grazing cover crops to cattle producers:

 

  1. Grazing cover crops extends the grazing season, leading to decreased costs of stored feeds.  Supplementation needs are also lessened due to the animal’s ability to preferentially graze to meet their nutritional needs. According to a study by Practical Farmers of Iowa, grazing cover crops can offset winter feed storage costs by up to $40,000. Of course, it is important to mention that labor costs increase, and grazing cover crops requires more intensive management of the land and cattle.  The cost may be offset by the reduced need to cut and bale excessive amounts of hay or corn silage. Feed should still be stored for emergency use, such as a failed cover crop or a stressed crop that has accumulated too much nitrate to graze.

 

  1. Grazing cover crops can improve cattle’s nutritional plane through preferential grazing.  Animals consuming a cover crop mix can choose plant parts such as leaves over stems which are higher in protein and non-fiber carbohydrates and lower in fiber.  Cattle can also choose less mature plants for the same nutritional reasons.  Therefore, by grazing a mix of annual crops, cattle can consume more protein and carbohydrates for performance than a balanced ration of roughages and grain supplements. Therefore, grazing cover crops can improve nutrition and eliminate the cost of ration balancing and mixing.

 

  1. By improving their nutritional plane, animal performance can increase when grazing cover crops.  Growing steers typically have increased feed intake when consuming cover crops as opposed to a mixed ration, which results in increased weight gains.  Heifers and cows on the higher plane of nutrition provided by cover crops can have increased reproductive performance.

 

  1. Grazing cover crops rotationally can have an added benefit of forage regrowth.  When animals graze a paddock for the first time, they open the top canopy and allow sunlight to reach shorter plants.  When the cattle are removed from that section, plant growth is stimulated and if allowed enough time, may recover sufficiently enough to allow the area to be grazed again.   Grazing regrowth is like bonus forage and can also contribute to decreased feed production and storage costs.

 

Integrating cropping systems with forage production and grazing benefits soil health, grazing livestock, and your pocketbook.  Grazing cover crops specifically benefits beef production by extending the grazing season, thereby saving on winter stored feed costs, improving the animals nutritional plane resulting in improved animal performance through increased intake and gains, and bonus regrowth can also be grazed, again saving on winter feed costs.  Don’t forget to take proper precautions before allowing cattle to graze cover crops. See my blog post: 6 Cautions When Grazing Cover Crops. 

4 Considerations of Water Quality for Beef Cattle

Typically, livestock water access and quality are considered during the summer months when heat stress is a concern.  I am choosing to address this topic during the cold winter months because as the temperature drops, below the thermal neutral zone animals consume more feed to increase metabolic heat production and water intake requirements increase with feed intake.  Water is often an overlooked nutrient during the winter months although access to quality water is important for maximum health and production.  Additionally, I have received a concerning inquiry regarding adding salt to water to keep it thawed during the winter months.  This could have deleterious effects on animal health. If a high salt water is provided with no alternate fresh water source, it could eventually lead to the animal’s death.  It is important to remember that water serves many functions in the mammalian body including making up 70% of the body’s mass, regulating temperature, growth, reproduction, lactation, digestion, metabolism, and many other functions we typically take for granted to function properly.  Therefore, access to quality water is important throughout all seasons, including the winter months.  Cattle can substitute snow if water availability is sparse but, access to quality water promotes maximum growth and reproductive performance.  Cattle are not particularly fond of cold water and therefore, while they can use snow in place of water, they prefer a heated water tank. Below are 4 items to examine when determining water quality:

  1. Total Dissolved Solubles (TDS).

This measures the minerals broken down within the water. Sodium chloride (NaCl), bicarbonate (HCO3­), sodium sulfate (Na2SO4), calcium (Ca) and magnesium (Mg) are some of the common solubles present in water.  Less than 1000 ppm TDS indicates safe water and will not cause any animal health concerns.  If the TDS is greater than 1000 ppm then further guidelines found in either the Ward Guide page 148  (http://wardlab.com/download/WardGuide.pdf) or Table 9-2 of Nutrient Requirements of Beef Cattle 8th revised edition page 156 should be referenced for Total Soluble Salts (TSS) guidelines

  1. Nitrate.

Health risks including abortion can occur in cattle drinking greater than 133 ppm NO3-N over long periods of time.  Nitrate poisoning and death can result from cattle consuming water greater than 221 ppm NO3-N.

  1. Sulfates.

High sulfate water can result in health risks from diarrhea to Polioencephalomalacia (PEM), a disruption in thiamin metabolism resulting in a neurological disorder.  It is recommended that calves are provided with water less than 500 ppm sulfate and mature beef cattle are provided with water less than 1000 ppm sulfate.

  1. Contaminants.

Other compounds can be found in water which are detrimental to cattle health. Below is listed common contaminants Ward Laboratories, Inc. tests for, but we are always happy to send samples out to other labs if you suspect another compound may be causing issues.  We commonly send out for selenium and lead.

Contaminant Toxic level (ppm)
Aluminum 0.5
Boron 5.0
Copper 1.0
Fluoride 2.0
Manganese 0.05
Zinc 5.0

 

In conclusion, it is important to provide quality water low in soluble salts, nitrates, sulfates and other contaminants to cattle in order to maximize production performance and ensure healthy animals.  Addition of salts to beef cattle water to keep it thawed during the winter months can increase the TDS thereby, having negative effects on cattle performance and health.  If you are struggling with keeping waterers thawed, remember cattle can substitute snow for water when necessary, and options such as heated tanks should be considered. If you are really struggling and need to get creative, put a salt water solution in water bottles and allow them to float at the top to prevent ice formation.