Sampling Bales for Forage Quality Analysis

Most ruminant livestock owners recognize that feed is the largest single expense in raising livestock. And within those feed costs, for owners of beef cows, sheep, and goat herds, winter feeding is the largest percentage of total feed costs. Having some advance knowledge of the quality of the stored forages being used for wintering can be important to understand the order in which the forages should be fed and whether our animals may benefit from supplemental feeding to make up for deficiencies in forage quality.

We occasionally are contacted by livestock owners who want to test forages but are not sure where to begin. Sampling stored hay and baleage is a simple process and can easily be done with a little advance planning. For purposes of this article, we will focus on forage stored as dry or wrapped bales.

Borrow a coring device if you can find one locally. These are commercially available for purchase, but by checking around you may be able to find one that can be borrowed from a neighboring farm, feed distributor, or the county Extension office. Most coring devices are made to attach to an electric drill, as shown in the photo.

Bales should be sampled in logical lots. For example, we should consider one test lot to be bales made from the same field the same day. A later cutting from the same field should be tested separately. Two different fields baled the same day should probably be tested separately, especially if they have different forage species.

For large round bales core toward the center of the bale from the curved edge. For both small and large square bales, core from the end of the bale through the middle of the bale. In each case we are sampling through bale layers to get a more representative sample. The more samples we take, the more we reduce variability of results. For large bales we should sample at least 10 bales and for small bales, 20. Mix the cored samples in a clean bucket and take a composite sample to send to the lab. Zip-lock plastic bags work well for holding the forage sample.

Wrapped wet bales can be sampled either before or after wrapping and fermentation. Research has shown (University of Wisconsin 1988-89) no significant change in crude protein or fiber levels in samples taken before and after fermentation in various forages.

Samples from wet bales, before or after fermentation, should be mailed early in the week to assure they get to the lab as soon as possible. Squeeze air from the sample bag and properly seal it. Forage that has undergone adequate fermentation should have enough acid to preserve the sample as it travels to the lab. Wet forage that has not been fermented may benefit from being frozen first and mailed in an insulated container.

We need to decide ahead of sampling time where we are going to have our samples tested. Penn State does not do commercial forage testing; however there are several commercial labs based in Pennsylvania and surrounding states that test forage. Deciding on a lab and contacting that lab ahead of time will allow them to get an information sheet to you so you can indicate which test options you need. This sheet needs to be completed and sent with your sample. You can also have test results mailed to individuals or companies that you work with on livestock nutrition. If you are not sure which test(s) to request, contact a person knowledgeable in animal nutrition.

Once you receive your results, if you are not sure about what the information means, seek input from fact sheets or individuals who have expertise and experience in animal nutrition.