As many of you, I often look at food labels while grocery shopping. I look at the calories, protein, fats, carbohydrates and ingredients and from there I make assumptions on how healthy that item is for me. Sure, I can look at a loaf of bread and can guess how healthy it is by on the brand or type of grain, but the label is able to detect the things you can’t see. The qualitative attributes of the bread and quantitative nutrition facts put together are what help you make the most informed decision.
So why is it we buy hay without knowing the quantitative lab results and base everything on the qualitative attributes - green, no weeds, not too dusty, and no traces of mold? If I gave you two bales of hay from different farmers and the hay seemed nearly identical, does that mean that they’re both the same quality? The answer is a big fat no!
Although scanning your hay to see if it has any mold or weeds is a good way to guess the quality, lab tests help fill in the blanks and best of all, they don’t lie. It’s the confirmation that you know exactly what you’re feeding your livestock.
Learning the basics of a lab report is essential to knowing the quality of the hay. The very basic metrics to look at are the crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), relative feed value (RFV), relative forage quality (RFQ), and total digestible nutrients (TDN).
CP is important because it lets you know how much protein your horse is consuming. Some grass diets that are low in protein might not have sufficient protein for what your horse needs. knowing the exact crude protein helps alleviate that.
NDF indicates how much fibrous material your horse is consuming and the higher the NDF, the less they will eat, which also means the fewer nutrients they’ll also be consuming.
ADF helps gauge the quality of digestibility of the forage. The higher the ADF, the lower the digestibility.
Putting this all together, think of CP as steak and potatoes, NDF as bread, and ADF as how well you digest the food. If I gave you lots of bread before you were to have dinner (high NDF) you’d have less room for higher-nutrient foods like steak and potatoes (CP) and with a higher ADF you’d have a harder time digesting. However, if you had a lower NDF and ADF, you’d have more room for steak and potatoes and you’d be able to digest better.
Believe it or not, this is what happens whenever I go to the Cheesecake Factory. I fill up on bread and then I can't even finish my meal. I also go for the brown bread because I think it's healthier. This all goes back to my opening paragraph.
Typically a high-quality alfalfa will have a CP over 20%, NDF <40% and an ADF <31%. Other important metrics such as the TDN, RFV, and RFQ are the big-picture scores that we use to grade the overall quality of alfalfa. Think of them as the three credit bureaus. I’ll get into those with more detail in a later post.
If you want to read about how to understand lab results in further detail, you can read this article by the University of California Alfalfa Workgroup.