For several years now, I’ve wanted to give my Austrian-born wife Dora the opportunity to answer some questions about her work as a licensed Straightness Training Instructor and certified natural hoof care professional, and her thoughts about the relationship between the two. Not, mind you, because she’s my wife, but because I daily witness the amazing work she does with horses, and recognize she has a great deal to offer the horse world.

Straightness Training, for those of you who may not be familiar with it, is a method of training that embraces the idea that the role of horse training is to acknowledge and address both natural and human-created asymmetries in the horse’s body and consequent movement to slowly and methodically bring the horse’s body into balance. It also recognizes that the goal of classical dressage wasn’t to win pretty ribbons at the local horse show, but to have a horse so athletically and mentally fit that it could successfully perform the high-level dressage movements as preparation for mounted warfare. Extensive study of the works of the old riding masters of dressage such as Pluvinel, Guérinière, and Baucher led Dutch-born founder Marijke de Jong to develop a system of unmounted and mounted exercises designed to strengthen and supple the horse’s body and create a strong, willing partner for whatever discipline you may be interested in. And it works!

Dora also studied natural hoof care with Liberated Horsemanship (which is how we met), and continued on to become a Certified Natural Hoof Care Professional and Field Instructor. And she’s noticed a strong connection between the results of her work in Straightness Training and her hoof care, which is one of the topics we’ll explore with her in our upcoming interview. So please join us for this Facebook Live Event, and bring your questions! And meanwhile, if you’d like to read more about Dora prior to the interview, you can learn more on her website.

Hope to see you soon…

Now that we’ve examined the caloric impacts of forage and processed feeds on the horse’s diet in Part 1 and Part 2, respectively, let’s take a look at what happens when grass pasture is added to the mix.

According to Dairy One‘s data, “pure” grass pasture has a Digestible Energy of 911 calories per pound with a Standard Deviation of 171 calories, based on 8,436 samples, while mixed, mostly grass pasture (MMG) has a DE of 962 calories with a S.D. of 127 calories, based on 18,544 samples. That translates to 95% of grass pasture having a DE value between 569 and 1,253 calories, while 95% of mixed grass pasture has a DE content between 708 and 1,216 calories. Why so much variation? Because so many factors affect the amount of sugar in, and therefore the calorie content of, grass. Time of day, time of year, amount of moisture, amount of sunlight, temperature – all these and more influence sugar content.

Attempts to actually measure pasture calories are far more common in the cattle industry than in the horse world, but the process is the same regardless of what species is grazing on it. Most often, a device called a plate meter – either the rising or falling type – is used to collect a series of measurements in a random manner throughout the pasture. These devices work by using a (usually) round, weighted plate of a known size to rest on top of the forage, and the distance from the plate to the ground is then recorded. The plate meter must first be calibrated, however, by taking a distance measurement on forage of the same type, clipping the forage under the plate to post-grazing level (with horses, generally 2.5 cm), and then drying and analyzing the forage sample for calorie content. Although simple in concept, many such samples are required for the calibration process to ensure reasonably-accurate meter measurements – a time-consuming endeavor. But by first collecting and analyzing these samples, a correlation between forage height (the distance measurement) and calories per square unit can be derived. After calibration, the amount of calories in a pasture can be fairly quickly and easily estimated by collecting and averaging a set of measurements. Plate meters are available with a wide range of features from several companies, but you can also construct your own for very little cost.

Using a homemade falling plate meter. Image from www.fieldcropnews.com.

But…before you spend either a fair amount of money on a manufactured plate meter, or a fair amount of time constructing and calibrating your own plate meter,  you may want to consider the following: Research has shown that horses’ rate of consumption of grass pasture varies greatly – and not in an entirely predictable way – depending not only on how much time per day they spend on grass pasture, but also on type of horse, temperature, time of day, season, grass height, grass composition, grass density and other factors, making any attempt at calorie calculations for grazing extremely difficult. For example, grazing researchers at North Carolina State University (Dowler, L.E. et al. 2012. “Determination of Pasture Dry Matter Intake Rates in Different Seasons and Their Application in Grazing Management.” Journal of Equine Veterinary Science 32: 85 – 92) note the following –

…this finding still suggests that horses have the potential to consume relatively large amounts of forage even when grazing for a relatively small portion of the day. These results suggest that DMI [dry matter intake] rate decreases with increased grazing duration and that the extrapolation of 24-hour DMI rates (eg, 2.5% of BW [body weight] in DM/d [dry matter per day]) to grazing periods of <4 hours may result in the underestimation of actual DMI. This may have implications for horse owners trying to manage BW/caloric intake of horses by reducing grazing time, in an effort to manage or prevent various diseases (e.g. laminitis, equine Cushing disease, metabolic disease, insulin resistance).

In other words, the relationship between pasture time and the amount of grass consumed is definitely not a linear one; rather, horses with limited pasture time tend to up their rates of pasture consumption, particularly in the first 4 hours. Simply put, this means: 1) even if the calorie content of a pasture is known, you cannot predict how many calories a horse will consume in a given amount of time with any reasonable degree of accuracy, and 2) you cannot use limited pasture time as a means of reducing calories without almost certainly limiting feed and/or hay availability as well. Interestingly, horses on continuous 24-hour grazing were found to voluntarily consume very close to their total calculated daily energy requirement, with no additional feed and/or hay required.

To further complicate this already-complex situation, some horses simply cannot eat green grass without developing metabolic problems, while others can happily eat green grass all day long and never have an immediate issue. Usually, the older the horse, the more often grass consumption becomes a complication. Because the reasons for these differences in tolerance are not well understood, it falls to the owner to determine whether or not grass causes difficulties for their particular horse. In keeping with my sentiments about mimicking nature in feeding, my personal preference is to allow horses only a very limited amount of green grass, based on the idea that the feral horse in his aboriginal environment is never in a position to eat mouthful after mouthful of green grass. Feral horses have evolved to eat sparsely-spaced dry, bunch grasses, and have to travel up to 12 miles every day to find sufficient calories; contrary to the increasingly common notion that domestic horses should have as much hay as they’ll eat, feral horses do not have unlimited access to forage, and certainly not to green grass. Expecting a horse to not overeat when plopped in the middle of the horse equivalent of a candy store all day strikes me as completely unreasonable.

Furthermore, I am becoming increasingly convinced that, like Type 2 diabetes in humans, we can help prevent the development of metabolic problems by feeding our horses as if they already had metabolic problems i.e. severely limiting the amount of green grass they eat. So, some sort of properly-designed (which, by the way, most of them are not) so-called “track system,” in which whatever forage present (mostly grass hay, perhaps with very small and widely-spaced-apart patches of green grass) is spread out over as large an area as possible to force the horse to move to be able to eat, seems to be the best situation for our domestic horses at present.

So there you have it: Although we can use average values to give us a rough idea of the calorie impact of grazing, just as we did with hay and with feed, the (even greater) number of variables affecting not only the forage itself, but also the horse’s rate of consumption, mean that such “guesstimates” should be used only as a very rough starting point for diet planning.

Based on what little published research has been done on the pasture dry matter consumption rates of horses, the average of the rates of consumption reported in these studies is 0.127 pounds of dry matter per 100 pounds of body weight per hour, plus or minus 0.032 pounds per 100 pounds body weight per hour. But keep in mind that that value is only reasonably accurate for longer grazing times – say, those over 3 or 4 hours. So instead of using that value, I’ve taken the 3-, 6-, 9-, and 24-hour measured grazing rate values from some North Carolina State University research, and extrapolated the intermediate values to create the following chart –

Make no mistake: This is a very rough estimate of calories consumed through grazing, as you’ll note by the wide range of values between the Low and High numbers. The next step towards improving the accuracy would be to use actual measured calorie values from your pasture, but, again, it’s still going to be an approximation.

In an attempt to make things a bit simpler, I’ve created an Equine Diet Planner in MS Excel, which you can either download for use on your own computer or use online within your browser.

As you can see in the screenshot of the Planner below, it incorporates the University of Minnesota weight calculator, which calculates Current and Ideal Weights, and then continues in the following section to calculate Required Calories by entering daily riding times.

The next section allows you to choose the amount and type of hay you’re feeding, or enter your own hay sample results, to calculate Total Hay Calories. Similarly, the feed section computes Total Feed Calories from the amount and type of feed, including allowing you to use values for a brand not on the drop-down list, which you can either obtain directly from the manufacturer or have tested by an independent testing laboratory.

The pasture grazing section has several choices for types of pasture, and then estimates Total Pasture Calories based on grazing time and whether or not your horse is muzzled. As I’ve noted above, pasture consumption is undoubtedly the most difficult to predict, but this will help give you at least a point of departure for diet planning.

Finally, the Summary section at the end adds together the previously-calculated calorie values to give an overall picture of your horse’s diet. It also cautions you when the calorie intake exceeds or falls short of the calories required to maintain proper (ideal) body weight by more than 5%.

I would strongly encourage you to use this Planner to develop a better understanding of what and how much your horse is currently eating versus what he actually needs to maintain a healthy body weight, and I would encourage you to share it – and the information/videos from the first two parts of this series – with your friends and your barn owner as well. Because of the very large number of variables involved, though, please remember that ultimately the only certain guide to whether or not you’re under- or over-feeding your horse is an honest eye!

To wrap up both this Post and this series, here are a few things to keep in mind:

  • Be honest about your horse’s weight. If you can’t be objective, ask someone else to take a look. Better still, use accurate measurements in the weight calculator and trust the results.
  • Be honest about how much you actually work your horse. Time spent tacking up, walking to and from the arena, etc. doesn’t count as work time, nor does simply sitting on your horse while he walks around. Think of it this way: If you wouldn’t be sweating and/or breathing hard doing what he’s doing, it’s not work and shouldn’t be counted as such.
  • Be honest about what and how much your horse is eating. Weigh everything. Do the math, and figure out the best way to feed only what he requires to attain/maintain a healthy weight, spread over a 24-hour period.
  • Have your hay tested. It’s relatively easy and inexpensive, and since hay should far and away constitute the bulk of every horse’s diet, knowing how many calories are in it is important.
  • Remember that you can’t feed muscle onto a horse. If your horse has a bad top line or otherwise lacks muscle mass, increase his work load and feed the consequent higher calorie demand; don’t expect to put healthy weight on a horse with just food. And don’t try to rush either the weight loss or the weight gain process; feed for his calorie requirements, and things will take care of themselves.
  • Consider your particular situation when planning your horse’s diet. If you board, you may have very little to no control over certain aspects of your horse’s diet, such as pasture time or brand of feed, so control what you can: Use a grazing muzzle, reduce the amount of feed, increase the amount of hay, etc.
  • Remember that things can, and do, change. Your horse’s current dietary requirements may be very different from his requirements several years ago. Be aware of the impact of pasture time on his diet, and adjust his diet accordingly.
  • Finally, be logical in your approach to feeding. Consider how nature feeds the feral horse, and remember that mimicking nature will generally yield good results. Keep in mind there is plenty of  bad advice out there, including from those with PhD and DVM after their names. If what is offered is inconsistent with what I’ve presented in this series of articles, be suspicious!

Much more to come…

Well, I guess turnabout’s fair play, so when Dr. Bruce Nock said he’d like to turn the tables and interview me, I could hardly refuse! The only thing Bruce has mentioned so far is that he wants to question me about what hooves can reveal about not only the feet themselves, but about the rest of the horse as well. And that’s a fascinating subject that can be immensely helpful to horse owners, because the hooves can, of course, tell us a great deal about how the horse is doing overall – a true “mirror into the horse’s state of being,” if you will. So please consider joining us for this Facebook Live Event, and have your questions ready!

I readily admit it: although I arguably have a large and diverse set of skills, I’m certainly no animal behaviorist. But as I’ve told students for many, many years, the smart person is not the one who knows everything about a particular subject, but rather is the one who knows where to find the right answers to his or her questions about the subject.

Dr. Bruce Nock is the person I turn to for those right answers about training and behavior. As an animal behaviorist and scientist with a research career spanning over 40 years, Bruce is the type of experienced, “data-driven” resource I can count on to give me unbiased and scientifically accurate information. I find that particularly important in the horse world, where incorrect theories and a general misunderstanding of the science of animal training seem to flourish. So please consider participating with Bruce and me in our upcoming Facebook Live Event discussion of animal behavior and training – I know you won’t be disappointed!

UPDATE: I happened across some new information on approximating current and ideal (target) body weight based on research done at the University of Minnesota. Because they use different formulae for different body types, their method appears to yield more precise approximations than previous methods, so my advice would now be to use their method to determine the target weight for your horse. You can find a description of their research and method here; note they also have an app available for Apple and Android devices at a minimal cost. I decided to create my own MS Excel-based calculator using their formulae that can be used or downloaded from here at no cost. Here’s a preview –

Humorous as Jared Lee’s cartoon may be, the overweight horse is genuinely at risk for increased health and performance problems. Overheating, poor performance, and metabolic disorders are all common consequences of excess body fat, causing discomfort, pain, and even loss of use for your horse, plus costly vet bills, headache, and heartache for you as the owner.

In Calories 101 – Part 1, we looked at several methods for estimating a horse’s current and target weights, and calculated the total number of calories necessary for maintaining a horse’s ideal body weight. And now, equipped with that necessary information, we can next take on the task of planning a proper diet for your horse. But first, I want to reiterate that I’m not an equine nutritionist; I’m merely a guy with an extensive math background who understands and can explain how to do the well-established calculations necessary for the task at hand! For advice about specific nutrients and nutrient ratios, please consult an equine nutritionist – ideally (in my opinion), one at a university, who’s not likely to be employed by the feed or supplement industries, to minimize the possibility of any specific product biases. So let’s get started!

First of all, absolutely everything in diet calculations is measured by weight. Not flakes, scoops, coffee cans, bales, pudding containers, or anything else volume-related. Weight. Period. So you’ll need some reasonably-accurate method of weighing out forage and feed. Yes, we could do some get-it-in-the-ballpark volume-based “guesstimating,” and possibly get within a factor of 2 by the time we figure out the actual amounts to feed, but why knowingly add to the already-present inaccuracies in horse weight and exercise estimations? You’ll need probably two different scales – a small platform-style scale (like a kitchen or postage scale) to weigh feed, and a hanging scale (like a fish scale) with a bag or hay net to measure forage.

When we talk about things that go in your horse’s mouth, it’s important to understand the difference in calories between what we’re actually feeding the horse, known as as-fed basis, and the values listed on any sort of analysis, called dry matter basis. The idea is a simple one: Everything your horse eats contains some amount of moisture. Whether it’s cured hay, with a relatively small water content of around 8 – 13%, or grass pasture, with much higher moisture values of 60% or more, that water needs to be accounted for in any calculations. So for an apples-to-apples comparison, dry matter basis is the way to go!

Our calorie estimations depend on two numbers listed in an analysis: the digestible energy (DE), which is a measure of the number of megacalories per pound in the sample, and the percentage of dry matter (% Dry Matter) present in the sample. For example, suppose my hay sample analysis results state that all figures are on a dry matter basis, and list a DE (Digestible Energy) of 1.000 Mcal/Lb. and a % Dry Matter of 90.000. Since the DE on my report is listed as a dry matter basis figure (in other words, with no water), but what I actually feed contains water, I need to do a bit of math to figure out how many calories are in a pound of what I’m actually feeding. First of all, 1.000 Mcal is equal to 1,000 calories; we have to multiply by 1,000 (i.e. move the decimal point 3 places to the right) to convert megacalories to kilocalories, which are what we usually refer to as just “calories.” Next, we have to multiply the calories by the % Dry Matter to figure out how many calories are in an as-fed pound of hay, so 1,000 × 0.90 = 900 calories per pound. The easy way to help remember that you need to multiply rather than divide is that the as-fed calories will always be lower than the dry matter calories. And now I know how many calories are in a pound of my hay!

So we’ll begin by talking about how to plan a diet using already-provided average values for forage and feed, and then we’ll describe how to properly collect and prepare a forage sample for actual laboratory analysis. And this seems like an appropriate time to mention my general approach to feeding horses.

As with hoof care, I believe our feeding perspective should emulate nature’s process of feeding feral horses in their aboriginal environment to the extent possible. Even though our horses’ energy (calorie) needs may at times exceed those of the feral horse, what they eat and the method of delivering it can still be consistent with nature’s methods. By doing so, we can minimize or even eliminate most of the feeding-related problems; laminitis, choke, insulin-related metabolic issues, and colic are all examples of conditions most properly-fed horses rarely suffer from. So keep this in mind as I describe the diet planning.

The table below lists the average DE and % Dry Matter values for some of the most common forages and grains, including fresh forages like grass pasture. These values come from a fabulous and absolutely free resource: Dairy One’s Interactive Feed Composition Libraries. While not every possible thing you might want to feed your horse can be found in their libraries, most typical items – and even some seemingly-odd ones (for horse people) like fresh pineapple forage – are definitely provided! And, being the nice guy that I am, I’ve calculated the As-Fed Basis DE calories as well –

Let’s begin with dry forage (hay), since that’s crucial to every horse’s digestive health, and should by far constitute the largest percentage of any horse’s diet. The absolute minimum amount of forage required to keep a horse’s digestive system working properly is considered to be 1% of his Target Weight per day, on a dry-matter basis. That means my 15-hand horse with an ideal weight of 1,014 pounds needs at least 1,014 × 0.01 = 10.14 pounds of dry-matter-equivalent forage each and every day just to keep things operating properly. According to the above table, grass hay has a % Dry Matter of 92.255, so the easiest conversion to as-fed would be 10.14 ÷ 0.92255 = 11 pounds. Remember, the as-fed amount will always be higher than the dry-matter basis amount, so dividing by the percentage of dry matter gives us the increase in weight due to water. The table also lists an average digestible energy (DE) content of 864 calories per pound, so feeding the absolute minimum forage requirement for my 15-hand horse would provide only 11 × 864 = 9,504 calories. But if you remember from Part 1, my 15-hand horse requires 15,210 calories per day to maintain his target weight, so we have a calorie deficit of 15,210 – 9,504 = 5,706 calories. So let’s see how much additional grass hay I would need to take care of this deficit.

If we divide the deficit by the average as-fed DE for our grass hay, we have 5,706 ÷ 864 = 6.6 pounds. So, by feeding my horse 11 + 6.6 = 17.6 pounds of grass hay per day, we’ve provided all of the calories necessary for him to maintain his Target Weight – no other feed required! Admittedly, that was more complicated than it needed to be, because directly computing the forage amount from the required calories will always more than satisfy the 1% requirement. So, making certain to use appropriate values to end up with as-fed weight:

Required Calories per Day ÷ Digestible Energy per Pound of Forage = Required Pounds of Forage per Day, or

15,210 ÷ 864 = 17.6 pounds

Simple enough, right?

…but now I need to mention there are several caveats to keep in mind when using the information. Keep in mind that the Digestible Energy number, like all of the numbers, is an average value based (in this case) on 66,310 samples, and, in reality, the values can and will vary over a fairly wide range. For grass hay’s DE, for example, those samples had a Standard Deviation of 111 calories. Without getting into the statistics behind these numbers, let me just say this indicates that 95% of the samples tested actually had a DE somewhere between 715 and 1,159 calories per pound (dry matter basis), or 660 and 1,069 calories per pound as-fed. Let’s try to understand the implications of that on our simple feeding program.

If you feed the originally-calculated 18 pounds of grass hay (yes, I rounded it up to the nearest pound) per day which used the average DE for the calculation:

18 × 660 = 11,880 calories per day with a DE at the lower end of the samples, leaving a deficit of 3,330 calories and thus underfeeding the horse by 22%

18 x 1,069 = 19,242 calories per day with a DE at the higher end of the samples, creating a surplus of 4,032 calories and thus overfeeding the horse by 27%

Conversely, if you adjust the forage amount for the lower and higher ends of the samples:

15,210 ÷ 660 = 23 pounds per day will be required if the hay is actually at the lower end of the samples measured

15,210 ÷ 1,069 = 14.23 pounds per day will be required if the hay is actually at the higher end of the samples measured

This same variability, of course, is present in the % Dry Matter numbers as well; more or less water present than the average value will have a potentially serious effect on the calculated as-fed amounts, thus throwing your feeding program off even farther! Hopefully, you’re starting to understand from this example why it’s so important to have your hay tested; you could very easily be underfeeding or overfeeding by a significant amount if your hay’s DE and % Dry Matter aren’t very close to the averages! Fortunately, hay testing is very easy and inexpensive, and will provide an in-depth look at the composition of your hay. A basic analysis from Dairy One, for example, will cost you only $23, and they’ll provide you with a postage-paid mailer for the sample, and email you the test results in very short order. The international handling fee is only an additional $7. Well worth the money! On to feed…

As we just saw in the above calculation, we were able to meet the calorie requirements of my 15-hand horse with 18 pounds of grass hay per day, and no other feed or grain. Horses are able to eat upwards of 2% of their body weight in dry matter per day, which translates to:

1,014 pounds body weight × 0.02 = 20.28 pounds Dry Matter

20.28 pounds Dry Matter × 0.937 Mcal/lb. DE = 19,002.36 calories

This means my horse is able to eat enough of this grass hay per day to meet all of his calorie needs even if he were being ridden or driven an hour every single day – no concentrates required! And in keeping with my philosophy about emulating nature’s process of feeding feral horses, let me also state now that I’m not of the opinion that horses should have unlimited access to hay – for a very simple and logical reason: Although feral horses have a theoretical 24-hour access to forage, in reality they must work hard to get that forage. Unlike our domestic horses, who can simply stand in front of a mountain of hay and gorge themselves, feral horses are eating sparsely-spaced dry, bunch grasses, and typically travel just under 12 miles every day to eat enough to satisfy their calorie requirements. While some domestic horses may eventually “self-regulate,” and eat only an amount necessary to meet their daily caloric needs, many others will simply continue to eat in excess – as evidenced by the tremendous number of overweight horses! So, your horse’s hay – whatever the required amount – needs to be parceled out via some slow-feeding method over a 24-hour period, thus emulating nature’s feeding method to the degree possible.

Feeding grain to horses came about at a time in history when horses were being used many hours per day, whether for farming, warfare, or transportation, and simply hadn’t enough time available to consume sufficient forage to maintain their body weight. So the use of “concentrated calories” came about to allow horses to meet their calorie needs and still be able to do heavy work. Unfortunately, that tradition has continued, and many horse owners believe or are told that their horses must eat feed or grain to remain healthy. That’s simply not the case; as you can see, most of our horses’ much lower calorie requirements can easily be met just by feeding hay. And because horses must consume at least 1% of their body weight (dry matter basis) in forage to maintain proper gut function, concentrate manufacturers generally list their feeding recommendations with that 1% forage + maximum concentrate as the starting point, followed by progressively higher amounts of forage + lower amounts of concentrate. Enough of that for now!

The following data was provided to me by Dr. Don Walsh, founder of the now-closed Animal Health Foundation, which supported laminitis research all over the world (thank you, Don!). Don collected this information directly from feed manufacturers because they do not list calories on their products; sadly, you have to contact them for calorie information. This list is by no means comprehensive, but it can give us a pretty good sense of the calories in most concentrates. I’ve listed them in order of ascending calories, as that’s more useful and interesting to me than the specific feed type –

As you can see, there’s quite a range of calorie values here – from a low of 900 to a high of 3,900! Incidentally, the feeds at the lower end are typically forage or ration balancers, which are products designed to make up for forage deficiencies in a particular geographic area. They aren’t intended to be major calorie sources, and are fed at lower amounts than complete feeds. If your forage analysis reveals deficiencies,  a ration balancer is the ideal way to make certain your horse’s vitamin and mineral needs are being met without adding a bunch of unnecessary calories to his diet.

Once equipped with the necessary feed calorie information (remember: you may need to call the manufacturer to get it), any feed component in your horse’s diet can be calculated in the same manner. Let’s use the numbers from our previous example: a 15-hand horse with a target weight of 1,014 pound requiring 15,210 calories per day, with 9,504 calories already provided by 11 pounds of grass hay. So if we use the most common calorie value for feed of 1,550 calories per pound (as-fed), our 5,706-calorie deficit can be met by:

5,706 ÷ 1,550 = 3.68 pounds of concentrate

So our entire diet calculates out to be 11 pounds of grass hay plus just under 4 pounds of feed per day. Remember that your horse must have the 11 pounds of hay; that’s a well-established absolute minimum! And with only 4 pounds more of feed – or just under 7 pounds more of grass hay – we’ll satisfy all of his calorie requirements. Anything beyond that is excess calories, which will be converted to fat! Based on what I see and hear on a daily basis, I’m certain these quantities seem quite small to you – especially the amount of feed. But keep in mind that that feeling exactly demonstrates my point: We’re grossly overfeeding our horses!

To wrap up Part 2, let’s discuss how to collect and prepare a forage sample for testing. The first step is to gather an appropriate sample, which needs to be collected in a random manner to be truly representative of our lot of hay. The table below will help you know how many samples to gather to create your final sample for submission –

This particular approach to sampling, including the numbers in this table, is called the Acceptable Quality Limit standard, and dates back to World War II and the manufacture of bullets for the armed forces. It provides a method of determining the characteristics of a group of items by testing a randomly-chosen number of items from that group; how many items need to be tested is a function of the total number of items in the group. For diet planning, the numbers can represent some unit of hay – either bales or pounds probably being the most logical. For example, suppose we buy 100 bales of hay from a dealer. Looking at the table, we see that randomly testing 20 bales will give us a very good idea of the characteristics of the entire 100-bale lot. For our purposes here, we’re interested in the two numbers we’ve been using to plan our horse’s diet: the Digestible Energy (DE) and the % Dry Matter.

I can’t stress the importance of a random sample enough. If we merely test the last 20 bales unloaded, for example, it might turn out they were leftover bales from an earlier crop, and therefore wouldn’t be representative of the entire lot. So we need to be a bit creative in our approach to picking the 20 bales. It’s really not difficult; for instance, as the hay is being unloaded, you could set aside every 3rd, then every 5th, then every 7th bale, repeating that pattern until you had the 20 bales. At any rate, once you have the 20 bales set aside, you need to reach into the center of each of the bales and pull out 2 or 3 handfuls of hay (you could also use a hay probe for sampling, which is like a long, small-diameter hole saw, but it’s not necessary). Take a pair of scissors, cut each of your handfuls into 2- to 3-inch pieces, and combine all of the cut samples in a clean, dry plastic bucket. Thoroughly mix the samples. Weigh out one (1) pound, place it in the sample bag, squeeze out the air, and seal the bag. That’s it!

And rather than have a downloadable file of the tables in this Post, I’ve decided I’ll create an MS Excel spreadsheet that’ll incorporate the content of all 3 parts of this series in one “spot,” and will automatically do all of the calculations for you!

In Calories 101 – Part 3, we’ll tackle what I consider the most challenging part of basic diet planning: the pasture. Stay tuned…