How to Properly Sample Hay
Use a good probe – The hay probe should have an internal diameter of 3/8 to 5/8 inch. The cutting edge should be at right angles to the shaft, and kept sharp. Dull probes will not obtain a representative sample. Core samplers that cut through a cross-section of a bale provide the best representation of stems and leaves. Avoid using open augers as they selectively sample leaves.
Sample at random – It is important to select bales at random from throughout the hay “lot” . Avoiding some bales and choosing others based on appearance will bias the sample. For stacked hay, samples should be taken from bales at various heights in the stack.
Take enough core subsamples – Taking at least 20 core samples from a hay lot minimizes sample variation.
Use the proper technique – For rectangular bales of all sizes, insert the hay probe 12 to 18 inches deep at a right angle into the center of the ends of bales. For round bales, the probe should be inserted at right angles to the outside circumference of the bales.
Handle samples correctly – Combine core samples from a given lot into a single sample and store in a sealed plastic freezer bag. Samples should be protected from heat or direct sun, and promptly sent to a laboratory for analysis. The sample should weigh approximately 1⁄2 to 3⁄4 pound. With larger samples, many labs will not grind the entire sample. Too small a sample will not adequately represent the hay lot.
Split samples correctly – To test the performance of a particular laboratory (or the sampling technique), a fully ground and thoroughly mixed sample should be split and submitted. Unground samples should not be split.