What’s in your hay?

Ted Wiseman, OSU Extension, Perry County (originally published in The Ohio Cattleman)

I don’t think that anyone would be surprised if I stated that getting hay made this spring was a real struggle.  Spring arrived with beef cows in some of the poorest body conditions that we have seen in years.  It is possible for an animal to starve to death with hay in front of them every day all winter.

My intent in this article is to simply illustrate the importance of getting your hay tested this year and to work with a nutritionist to establish a feeding program. Forages analyzed from this year indicate that quality is going to be an issue again.  Many of the first cutting samples from this year have protein levels in the single digits and total digestible nutrient (TDN) levels, in the 30s and 40s.  To put this into perspective straw has a crude protein level around 4 percent and TDN levels between 25-55.  To make matters worse we have an extremely low supply of forages and straw this year.

The following three tables focus mainly on the energy levels in forages and at three different stages of beef cow production.   In this scenario we have a 1200-pound cow and keeping dry matter intake (DMI) constant at 2 percent.  At each TDN level for forages analyzed it shows how much hay, corn and soybean meal it would take to meet these requirements.  These tables equate to requirements of a beef cow at 9 months gestation (Table 1), at calving (Table 2) and at peak milk production (Table 3) respectively.

Forage Analysis Amount Fed on an As-Is basis (lb/day)
TDN CP Hay Corn Soybean Meal (49.9 % CP)
0.35 6.0 20.1 6.7 0.3
0.40 6.0 22.6 4.7 0.4
0.45 7.0 24.2 2.3 0.1
0.5 8.0 25.4 0.6 0
0.55 9.0 26.7 0 0
0.60 10.0 26.7 0 0


Forage Analysis Amount Fed on an As-Is basis (lb/day)
TDN CP Hay Corn Soybean Meal (49.9 % CP)
0.35 6.0 16.5 8.7 1.4
0.40 6.0 18.1 7.0 1.5
0.45 7.0 20.4 5.1 1.1
0.5 8.0 23.4 2.6 0.6
0.55 9.0 25.9 0.7 0
0.60 10.0 26.7 0 0


Forage Analysis Amount Fed on an As-Is basis (lb/day)
TDN CP Hay Corn Soybean Meal (49.9 % CP)
0.35 6.0 13.8 11.5 1.3
0.40 6.0 15.2 10.1 1.4
0.45 7.0 17.1 8.5 1.1
0.5 8.0 19.5 6.5 0.6
0.55 9.0 22.8 3.8 0.1
0.60 10.0 26.7 0 0

I cannot stress enough how important it is for you to have forages analyzed this year.  Just because we can balance a ration on an excel spreadsheet doesn’t mean that it will work.  The ruminant digestive system is far more complex.  With TDN levels as low as what we have this year, some lower than straw, it is extremely important to work with a nutritionist now.

With tight supplies across the state you will want to determine your inventory and quality early as possible.  This will give you time now to purchase additional forages or supplements instead of scrambling to find them this winter.  If you do need to purchase additional hay, hopefully it has an analysis on it, unfortunately many times they do not.  Visual estimation of the nutritive value of hay is nearly impossible.  Visually you can estimate maturity, condition, purity, color and smell.  Nutrient levels will also vary depending upon level of legumes compared to grasses in the bale. If purchased hay has not been tested, it should be sampled and analyzed so you can plan your feeding program.

Many of the county extension offices or local feed dealers have a hay probe that you can use to collect samples.  It is extremely important to follow the correct sampling procedures for accurate results.  Forage tests are relatively inexpensive compared to the value of knowing what you are feeding and when it is needed.