Rain in the fall usually is welcomed despite the delays it causes with crop harvest. Pastures and alfalfa benefit from extra growth and winterizing capabilities. Wheat and other small grains get well established as do any new fields of alfalfa or pasture. And the reserve moisture stored in the soil will get good use during next year’s growing season.
But rain does reduce the feed value of corn stalks in fields already combined, points out University of Nebraska Extension forage specialist Bruce Anderson. And this fall many fields have had some pretty heavy rain on the stalks.
Rain reduces corn stalk quality several ways. Most easily noticed is how fast stalks get soiled or trampled into the ground when fields are muddy, says Anderson.
Less noticeable are nutritional changes. Heavy rain soaks into dry corn stalk residue and leaches out some of the soluble nutrients. Most serious is the loss of sugars and other energy-dense nutrients, which lowers the TDN or energy value of the stalks, according to Anderson. These same nutrients also disappear if stalks begin to mold or rot in the field or especially in the bale. Then palatability and intake also decline.
There is little you can do to prevent these losses. What you can do, though, is begin to supplement a little earlier than usual, Anderson suggests. Since weathering by rain reduces TDN more than it reduces protein, consider the energy value of your supplements as well as protein content.
Anderson says the bottomline is that weathered corn stalks still are economical feeds – just supplement them accordingly.
If you are baling corn stalks to store as extra winter feed, Anderson says, “before you feed those bales, find out what they have to offer nutritionally. Sample and test your bales as soon as possible so when snow gets deep or other feeds run out you will already know how to best feed your corn stalk bales.”
From his experience, Anderson says it is surprising how variable the protein and energy content can be in corn stalk bales. He says, “I’ve seen protein as low as 2% and as high as 7%. Since dry pregnant cows need 7 to 8% protein in their diet, those high protein bales will need only a little protein to adequately care for the cows. But those 2% bales will need quite a bit of supplement to keep cows in good condition.”
He suggests choosing a protein supplement that is nearly all natural and is mostly rumen degradable. Maintenance-level forage diets need degradable protein for the rumen microbes, but remember that urea and other non-protein nitrogen sources aren’t used quite as well, he says.
As a final reminder, Anderson says it is a good idea to test all of your stored hay in order to get the most value from their hay and profit from their animals.
He emphasizes that the most important step, and sometimes the most difficult step, in sampling hay is deciding which bales and stacks should be included in each sample. Ideally, each sample should include only bales that were produced under nearly identical conditions.
Anderson says, “Obviously, the place to start grouping is to separate different types of hay, like alfalfa or cane or meadow hay. But each cutting of hay probably is different from the other cuttings also, so there is another separation. And no two fields or meadows are ever exactly the same, especially if they were cut more than two days apart, so that makes another grouping. And what if part of the field was rained on before it was baled? It is very likely that hay made without rain damage will be different from hay with rain damage.”
After you’ve made all these separations, which could result in quite a few groups of similar bales, then you are ready to sample. From each group gather twelve to twenty cores from different bales or stacks and combine them into one sample. Be sure to use a good hay probe that can core into at least one foot of the bale.
Finally, send these samples to a certified lab for tests of protein and energy content and any other nutrients of interest to you. Then use this information to feed your cattle as profitably as possible.