Proper hay sampling holds the key to accurate forage testing
Proper hay sampling for an accurate forage test may not be new, but it sure is important.
April 12, 2012 - Author: Phil Kaatz, Michigan State University Extension
The hay season is just around the corner for Michigan producers and the importance of proper hay sampling technique cannot be emphasized enough to ensure an accurate forage test. The “eyeball method” of determining forage quality just doesn’t cut it if you’re trying to balance the ration. For larger livestock operations, the challenge is how to get a representative sample from thousands of tons of highly variable plant material. For the smaller livestock producer, this task may never take place. In either case, the variation caused by sampling variation may cost Michigan’s forage industry millions of dollars by over-valuing or under-valuing forages. The hay buyer, hay seller and the livestock producer can all benefit by having a standardized sampling protocol.
The following key points have been around for years and should provide the right steps to help insure an accurate forage test:
Identify a single “lot” of hay. A lot should be from a single cutting, a single field and variety, and generally less than 200 tons. Do not mix cuttings, fields, or hay types.
When do I sample? Samples should be taken as close to the time of feeding or point of sale as possible.
Use a coring device or probe. Hay probes generally have a 3/8- to 3/4-inch diameter shaft and are 12 to 24 inches long. Grab samples or flakes of hay should never be considered as a representation of the lot of forage. A sharp tip that may or may not be serrated that can cut through the sample should be used.
Two examples of forage probes that can be used for dry hay
Notice the serrated edge of the probe in the right picture.
Take random samples. Avoiding bales that look good or bad is the idea to help remove any bias.
Have a minimum number of cores. Recommendations of 10 to 20 cores are adequate to represent most lots of hay. Larger lots of hay should have an increased number of cores (20 to 35) to ensure variation is kept at a minimum. Small square bales should have one core per bale whereas larger bales should be cored two to three times.
Use proper techniques.Sample the butt ends of square hay bales probing to the center of the bale. For round bales, sample on the round side probing towards the center of the bale. Sample size should total about half a pound.
Handle samples correctly.High moisture or wet samples should be double-bagged in sealed, plastic bags to ensure proper dry matter measurements. Samples should be shipped as soon as possible and kept from direct sun exposure.
These procedures can help producers due to the fact that sampling variation is more variable than the labs that are doing the testing. They can only provide testing on what comes into their labs. A poor sample can never give the best results.