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Take a Better Silage Sample with These 5 Tips

August 11, 2020

Taylor Leach

We’ve reached that point of the year when choppers are brought out of the shed, silage wagons are dusted off and tractors race to the fields to ring in another corn silage season. It’s an exciting, yet stressful time for dairy producers because the corn that is harvested from these fields will likely feed their animals for the next 12 months. And if the quality of the homegrown crop is not good, then outside feed will need to be purchased.

Growing conditions along with hybrid selection, disease pressure, time of harvest and stage of maturity vastly differ from year to year, which makes it difficult to determine what forage quality of the crop will be. Because of this, it has now become a necessity to take a proper silage sample in order to bring more reliable results and consistency to your total mixed ration.

The largest error in forage analysis is improper sampling methods on the farm, according to University of Wisconsin researchers. If you plan on harvesting silage for your dairy operation in the coming weeks, here is a quick refresher to help you take better silage sample this harvest season.

  1. Make sure the sample represents the entire silage face. – When gathering silage samples, it is important to make sure that the sample serves as an accurate representation of the entire silage face. Researchers from the University of Wisconsin-Madison recommend these tips when it comes to gathering silage samples from bunkers, silage bags or silos:

  • Bunker - Using a loader bucket or face shaver, carefully scrape across the face—either vertically or horizon- tally depending on how you are feeding—to create a pile of silage on the bunker floor. Do not scrape spoiled material from the top of the silo into the sampling or feeding pile.

  • Silage Bags - Collect several hand grab samples from different locations across the silage face. After silage has been removed from the bag, a second set of hand grab samples can be taken from the newly exposed face to increase the number of sample locations for a total of 10 grab samples. Take 8 to 10 core samples through the sides of the tube at various distances along the length.

  • Silo - Collect 1 to 2 pounds of silage from the silo unloader while it is operating. Collect samples from morning and evening feedings of the same day. 

  1. Mix it all together. - In order to obtain better data from the entire silage harvest as a whole, several sub-samples should be taken and mixed thoroughly together. Place the mixed sample in a clean plastic bag or airtight container and freeze or refrigerate until the sample can be shipped. 

  2. Mail samples sooner rather than later. – When sending forage samples to the lab, it is important to get them in the mail as soon as possible to help prevent mold and excess fermentation from occurring. Label your samples with your name, address, sample number, forage type and mixture and try to mail them early in the week to avoid weekend delays.

  3. Utilize the freezer. – If you are unable to send samples off to the lab right away, be sure to freeze the silage to prevent it from spoiling. Ideally, samples should be refrigerated or frozen and sent to the lab overnight with an ice pack. However, if the sample has normal moisture content and is well-sealed, it can be sent within two days, according to Colleen Jones and Virginia Ishler, extension dairy specialists from Penn State University. 

  4. Keep sampling! – Even after corn silage harvest is over, it is important to take multiple samples throughout the year. Recheck dry matter of silages at feed out. Fiber and protein are not likely to change significantly during storage but moisture can change, according to University of Wisconsin researchers.

While corn silage harvest season can be a stressful time of year for any producer, it is imperative to take forage testing seriously to better understand the quality of forage you are providing your herd. If you have questions during the forage sampling process, reach out to your nutritionist or local extension agent for help.


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