We sent off a sample of our hay and got the results back yesterday:
(All values are on a dry matter basis)
%Crude Protein (CP): 6.4
%Available Protein: 5.6
%ADICP: 0.8 (Acid Detergent Insoluble Crude Protein)
%Adjusted Crude Protein: 6.4
Soluble Protein % CP: 31
Degradable Protein % CP: 66
%NDICP: 2.1 (Neutral Detergent Insoluble Crude Protein)
%Acid Detergent Fiber: 45.3
%Neutral Detergent Fiber: 71.9
%Lignin: 8.5
%NFC: 18.5 (Non Fiber Carbohydrates)
%NSC: 11.7 (Non Structural Carbohydrates)
%Starch: 1.8
%Sugar: 9.9
%Crude Fat: 1.9
%Ash: 3.43
%TDN: 53 (Total Digestible Nutrients)
NEL, Mcal/lb: 0.39 (Net Energy for Lactation)
NEM, Mcal/lb: 0.44 (Net Energy for Maintenance)
NEG, Mcal/lb: 0.19 (Net Energy for Gain)
Relative Feed Value: 69
%Calcium: 0.44
%Phosphorus: 0.08
%Magnesium: 0.14
%Potassium: 0.71
%Sodium: 0.037
PPM Iron: 68
PPM Zinc: 19
PPM Copper: 9
PPM Manganese: 75
PPM Molybdenum: 0.2
%Sulfur: 0.11
%Chloride Ion: 0.14
%Lysine: 0.22
%Methionine: 0.08

So the quality of this hay is not great. Six percent crude protein is barely above values for various straws, which may be around 3-4%. We knew that it wasn't going to be that great however because of the large amount of overly-mature timothy in the mix. Everyone around here will tell you that the weather played a big part in the quality of the hay they got. A few days of rain at the wrong time and that was that. Slightly more than half (53%) of the hay is considered digestible (Total Digestible Nutrients, TDN). So half is waste. Oh well, hopefully next year will be better. Meanwhile, we supplement with grain.