Myth:  When thinking about purchasing or putting up feed for next winter, there’s not many options to keep feeding costs down.

Beef Cattle Mythbuster

Dr. Don Llewellyn¹, Gary Rohwer², and Sarah Dreger^1
1WSU Department of Animal Sciences and WSU Extension, Pullman, WA
²Bar Diamond, Inc., Parma, ID

Myth:  When thinking about purchasing or putting up feed for next winter, there’s not many options to keep feeding costs down.

Answer:  Help is on the way!

First, the realities, here we go again: Hay prices are through the roof, grains doing the same, and anyone that eats food or puts fuel in a vehicle is back on their heels wondering where this inflation came from, basically overnight.  The fix will take time.

Being the eternal optimists that we need to be, we are taking notice of every bit of feed we are going to put into the cows next winter.  This is a big decision with hay prices such as they are, and there won’t be much margin left.  That said, producers are going to be looking far and wide for alternatives when it comes to feed (both in types of feeds and how to categorize and feed them).  It may seem strange to be focused on winter feeding at this time of year when the cows have just been turned out on pasture, but lots of feed will be purchased soon and many decisions will need to be made.

Gary, Sarah, and I have been pondering the question: Can we take the best available science in beef cow nutrition and apply it in a reasonable and science-based way to assist in making the tough decisions in strategies to feed the cows next winter and keep them and their calves in good shape and healthy?  We think there is hope and we would like to provide some ideas.

Let’s consider three categories of feeds: base forages (hays, straws, and other harvested feeds; and dormant low-quality grass for grazing), which are generally of fairly low in quality, but are utilized well by cows that have relatively low nutritional requirements such as nonlactating spring calving cows.  Energy feeds are those which can be used to increase the caloric density of the diet.  These include grains and other starchy feeds such as corn, barley, and triticale, just to name a few (typically the cost per unit of energy is lower for these types of feeds than forages).  Fats fall into the energy feed category as well, but there are limits in the amount of fats we can feed because of their effect on rumen function, fiber digestion, and palatability.  Finally, there are the protein feeds such as oilseeds like canola meal, or another alternative is dried distiller’s grains.  In addition, alfalfa hay is a classic protein supplement in the Pacific Northwest.  Interestingly, there is a subcategory that includes moderate quality hays that are fairly rich in protein and have the ability to supply a good amount of energy.  So, what do we feed?  Low-quality forages with protein and/or energy supplementation?  Moderate quality hay by itself?  It all depends on the cost and the arrangement of the feeds in the diet.

This is where we come to “modeling” a beef cow diet.  Actually, we can do diet modeling for beef cows, heifers, pregnant, nonpregnant, yearlings in dry lot or on pasture, growing cattle, finishing cattle, you name it!  So, what is beef cow diet “modeling”?  Essentially it is taking a systematic, scientific (but applied) look at what feeds you have, their prices, and how they fit with the nutrient requirements of the cows.

Fortunately, we have a great resource to get us started.  This is the eighth revised edition of the Nutrient Requirements of Beef Cattle (nutritionists call it the “Beef Cattle NRC” and this version was released in 2016).

The National Research Council (NRC) has published seven editions since it was started in 1944.  This document serves as a guide for nutritionists for the development of feeding and nutrition programs for beef cattle.  It incorporates the most recent research results and current state of knowledge in beef cattle nutrition and feed ingredients, and provides a perspective in using this information in beef cattle production.

In a practical sense, how do we “model” a beef cow diet?  Answer: We have tool.  Complementary to the “2016 Beef NRC” described above, we can employ the Beef Cattle Nutrient Requirements Model (BCNRM).  It is basically a mathematical tool to help us work our way through the development of a feeding program.  Many users may find it a bit cumbersome, but ruminant nutritionist (like your Beef Mythbuster team) find things like this pretty exciting.  Instead of looking up all of the nutrient requirements for your cattle in tables and hand-calculating nutrient delivery from your feeds, the model does it for you.  It’s an Excel-based tool that allows us to define the type of cattle we want to feed, understand the nutrient requirements of those cattle, balance a diet (grazed or harvested forage, supplemented or not supplemented), and ultimately arrive at a daily cost for feeding the cattle.  While there are many components and tabs to navigate the tool, in general it looks like this (our example is using crested wheatgrass hay, alfalfa hay, and barley grain, and balances for protein and energy, and assumes the producer is providing free choice mineral supplement separately):

National Academies of Sciences, Engineering, and Medicine. 2016. Nutrient Requirements of Beef Cattle: Eighth Revised Edition. Washington, DC: The National Academies Press. https://doi.org/10.17226/19014.

It also has the capability to generate many summary tables that you can save for reference:

National Academies of Sciences, Engineering, and Medicine. 2016. Nutrient Requirements of Beef Cattle: Eighth Revised Edition. Washington, DC: The National Academies Press. https://doi.org/10.17226/19014.

How it works (the process):

• Define the animal you are feeding (age, sex, body condition, initial and final body weight, mature body weight, breed type, breeding system [straightbred, crossbred, etc.], breed, pregnancy status, calf birth weight, days since calving, milk production, target calving age (first calf), and calving interval.
• Define management—feed additives and implants (relevant for growing and finishing cattle), grazing unit size, days on pasture, available forage mass, etc. Some of these will apply to your cattle and some will not.
• Define environment—wind speed, previous temperature, current temperature, relative humidity (previous and current), storm exposure, lowest night temperature, hair depth, hide, hair coat, panting, and mud depth.
• Some advanced options are defined for maintenance factor, adjustments to required NE_m, dry matter intake (DMI), ionophores, implants, ruminal pH, efficiency of conversion of digestible energy to metabolizable energy, and others.
• There are substantial feed tables included in the program. If you have the nutrient analysis for your own feeds those can be used in the model as well.  These are the dietary inputs.  A price per ton for each feed is entered into the model which will make it possible to have a daily cost to feed your cattle generated.
• When the animal characteristics are defined, and feeds and feed prices are in the model we can balance the diet. For example, with dry spring calving cows in the third trimester of gestation, one would likely choose some relatively low quality base feed (because the nutrient requirements of those cows will be fairly low).  We would take your available feeds, generate an estimate of intake of the forages and determine what requirements are being met and those that aren’t. Use your available base forages, protein feeds, and energy feeds, to balance for protein and energy manipulating the available feeds to provide for the producers’ desired level of performance (gain, body condition score, etc.).  We can also balance for vitamins and minerals, but many producers will provide those supplements free choice.  A key point as well is that by proper modeling of the diet, producers can avoid over- or under-feeding the various nutrients which can have performance and/or environmental implications.

As you can imagine, there was a lot of research data that went into the model and made all of the inputs (i.e. we can call them assumptions) possible. After working through the process, the producer should have a pretty good handle on how much will be required for each class of feed and an estimate of the daily cost to feed the cows during the time period set forth.  There are also some very interesting outputs on the source and metabolism of the various nutrients (but that discussion is for a workshop).  And you can do all of this for your cattle to evaluate any time during the cows’ production cycle.  Pretty cool, eh?

There you have it; the myth is busted!  We can navigate feed prices in a scientific way from the cows’ perspective.  What we do in beef cow nutrition modeling won’t make the commodity prices of feed go down, but at least we know we are getting the most out of every pound of feed provided to the cows.  Stay tuned, modeling beef cow diets seems like a great idea for a series of WSU Extension workshops for next fall and winter.  It will also give us time to cover interpretation of results and learn more about ruminant nutrition.  If you are interested in a nutrition workshop in your area next fall/winter, let us know (don.llewellyn@wsu.edu), we can make that happen!  Have a great spring!