In my last article “Feeding Cows in the Cold,” we talked about cold stress and how to adjust rations to meet the increased energy demand animals experience under cold weather. The example I used was feeding grass hay, and we pretty lightly tossed out a number of 57% TDN in our hay.
When it comes to developing rations for our animals, knowing the products we have to work with is critical. At this time of year with cold weather stress and either late gestation or milk demand increasing the nutrient requirements in the cow herd, not knowing if our hay is at 57 or 62% can have pretty major consequences. Due to variations in weather from year to year, major differences in harvested forages can occur, even when the same field was harvested at a similar time as last year. With that in mind, it’s easy to see how we can easily be under or overfeeding our animals.
To prevent this, any major feedstuff that is used in a ration needs to be tested. With some feedstuffs like silage, sampling at harvest is the preferred method. Post-fermentation, silage should match closely with analysis done at harvest, however, if you suspect that proper fermentation did not occur, sending a sample in to double check may not be a bad idea. If you didn’t get around to sampling your silage pile at harvest, it’s not too late to take a few samples now.
Silage should be sampled by lot. A lot is silage that will be similar in quality, the same hybrids, field location and condition, and stage of maturity at harvest. This is a bit harder to after harvest. If you are sampling from a bunker, load your normal amount of silage into a ration mixer and turn it on. Before adding anything else, either unload onto a clean area or catch several handfuls. A silo is even more difficult to sample randomly. We don’t want to have the silage sit around too long and spoil after sampling, so try and sample over the course of one day by taking a few handfuls at morning and night feedings from the silo’s unloading auger.
Once we have our lot sampled, we want to mix all the samples together. Dumping them in a five gallon bucket and doing a bit of hand mixing will do just fine. Dump the mixed sample out and split into 4ths. Keep 2 of the quarters and discard 2. Mix and repeat the splitting and discarding until you have 1 – 1 ½ quarts left. Put this into a 2 quart zip-lock freezer bag and squeeze out as much air as possible. Label with your name, address, forage type, and a sample ID. Store in a cold place or freezer until you can ship to a testing lab.
Hay is best sampled with a hay probe to ensure a random sample and just like silage should be sampled in lots, each containing hay of a similar type, harvest date, and field location. The probe should be inserted at least 12-18 inches into the bale and needs to core an area with uniform stem and leaf distribution. In round bales, this means coring into the rounded edge in the center of the bale. For squares, core the center of the bale’s end.
Take one sample per bale, and put into a bucket where you can mix and quarter with the same method used in silage above. In general, 15-20 large round or square bales per lot should provide an adequate sample. Once you’ve mixed and reduced the sample down, put into a 2 quart zip-lock freezer bag. Label the bag with your name, address, forage type, and sample ID. Store in a cold location or freezer until shipping.
If you don’t have a hay probe on hand, give your local extension office a call. Often times they will have one that can be checked out or help you find one. They may have sample bags and shipping materials available as well. Our office in Cedar County has probe, bags, and shipping materials available to producers for free.
Before sending off for testing, we need to select which analysis to have run. Chemical wet tests are traditional method used to sample forages and may be selected for testing specific nutrients or assured accuracy. Near-infrared reflectance (NIR) methods use a computerized method to quickly and reliably analyze feeds. Proper labeling of the feed is critical to ensure the correct feed library is used for analysis, but with low cost and quick turn-around times, NIR is an attractive method to select. One feedstuff that still requires chemical analysis are distillers byproducts. Due to the high fat content, NIR often underestimates energy content of distillers products.
Most commercial labs offer packages of either wet or NIR analysis that meet the needs of basic producers. In general beef and dairy cattle feeds should be sampled for; moisture content, crude protein (%CP), and energy (TDN). Calcium, phosphorus, vitamin A, and other trace minerals may also be worth testing for, depending on cost and importance of variation in the ration. For dairy animals, Relative Feed Value (RFV) and Relative Feed Quality (RFQ) should also be included to assist with determining forage intake and digestibility.
Sampling your feedstuffs or getting accurate analysis on purchased products is the cornerstone of a good nutrition program for your beef herd. If you want more information, go online and search for or ask your local extension office for NebGuide G331 Sampling Feeds for Analyses. As always, the extension beef specialist assigned to your local extension office are always happy to help with personalized assistance as well.
-Ben Beckman is a beef systems Extension Educator serving the counties of Antelope, Cedar, Knox, Madison and Pierce. He is based out of the Cedar County Extension office in Hartington. You can reach him by phone: (402) 254-6821 or email: firstname.lastname@example.org .