Friday, December 2, 2016

Interpreting Hay Analysis

I finally had my hay tested! This is something I've been wanting to do but since I don't have any "special needs" horses, it was on the back burner. Plus I wanted to wait until a large supply was delivered so it would be relevant for a while.

Here are the results for the 2nd cutting orchard grass that I feed spring through fall:

Here are the results for the 1st cutting orchard grass/timothy mix that I feed in the winter:

I had to do a lot of research when I received these results because to be honest I had no idea what many of these values should be. I had a general notion about desirable protein content in hay and knew that lysine is an important amino acid. I knew that people with metabolic horses are concerned about NSC (non-structural carbohydrates) in hay, but I didn't know how to calculate that with what I was given (or how concerned I should be about it given that my horses have no known issues).

So after doing a lot of research and some calculations, I'm satisfied with the digestible energy, protein, and NSC:

  • DE (averages .76-.94 Mcal/lb): within range for both (.86), suggests ~29 lbs of hay per horse per day needed (based on light work recommendation of 25 Mcal/day for 1400 lb horse)
  • Crude protein (typically 8-10%): slightly low for 1st (7.7%), high for 2nd (12%)
  • ADF (30-35%): slightly high for 1st (37%), ok for 2nd (32%)
  • NDF (40-50%): high for both (61% and 55%) <-- suggests low palatability
  • NSC (WSC + starch, <12% for low sugar/starch diet): good for both (~10%)

Here's a table that shows what the horses would consume when eating 2% of their bodyweight in hay plus 1.5 lbs of Triple Crown 30% per day (I only totaled it for the 1st cutting because when they're eating 2nd cutting spring through fall, they are on grass more than half the time):

I also calculated mineral ratios for the hay alone and in combination with the TC30:

I thought it was really interesting that some ratios were off in the hay but corrected by the TC30. It seems that the TC30 is indeed fulfilling its purpose as a ration balancer!

The "required" column in all of these tables comes from the following sources:

National Research Council
Dr. Getty's How to Interpret Your Hay Analysis Report
Understanding Horse Nutrition (this is a great resource on all aspects of feeding!)

For help with unit conversions (e.g., lbs to grams, ppm to grams): try these conversion tables from Equi-Analytical. Here are some I found useful:

lb     x   453.6   =  g
mg/kg  x 0.4536  =  mg/lb
ppm     x  0.4536  =  mg/lb