Feed Sampling & Analysis
Representative Sample
• Identify a “lot” of hay
• Same field harvested within 48 h
• Other variables – variety, soil, weeds
• Small sample represents “a lot” of hay
How to Take the Sample?
• Use a strong, sharp coring device
• At least 12” to 18” long
• Right angle to bale
Where to Take the Sample?
• Ends of square bales
• Sides of round bales
How Many Bales to Sample?
• Minimum of 20 bales per “lot”
• Take more if variability high
• Sample bales at random
•Around the entire stack or yard
•Different heights
•Have a plan
Pasture Sampling
• Identify uniform area as “site”
• Approximately 20 plots per site
• But, forage maturity changes
Silage Sampling
• 3 to 5 handfuls from the middle of a
load
• Plastic bag, refrigerate immediately
• Repeat several times during day
Grain Sampling
• Grain probe
• At least five cores
• Approximately 1 lb total
Handling Samples
• Combine “cores” of one “lot”
• Hay or grain – store in sealed freezer
bag
• Fresh forage – store in paper bag
• Send to lab quickly
Proximate Analysis
• Water
• Crude protein = %N x 6.25
• Crude fiber (CF)
• Ash
• Ether extract (EE)
• Nitrogen-free extract (NFE)
Proximate Analysis
• Nitrogen-free extract (NFE) =
• 100 – (%water + %CP + %CF + %Ash +
%EE)
• Estimates non-structural CHO
Total Digestible Nutrients
• %TDN =
• (% dig x %CF) + (% dig x %NFE) + (% dig
x %CP) + (2.25 x % dig x %EE)
• (0.50 x %CF) + (0.90 x %NFE) + (0.75 x
%CP) + (2.25 x 0.90 x %EE)