Thistle control, hay testing and oat and brassica quality
University of Nebraska Lincoln
As October approaches and harvest starts, don’t forget about thistles plaguing your pastures.
Fall, specifically October and early November is a key time to chemically control thistles in pastures.
More herbicides can be used and the small size of musk thistle seedlings and new growth of Canada thistle is key to effective chemical control. During the season you may have seen thistles in your pastures, if you scout those areas you will most likely find rosettes of musk thistle forming or new Canada thistle growth. While in the rosette stage, thistles are more sensitive to herbicides and can be effectively controlled chemically.
There are many herbicides labeled for thistle control. Always read and follow all label directions. The use of trade names is for educational purposes only and not an endorsement. When choosing your herbicide for spraying thistles, proper identification of the thistles can help make those decisions. Several products are effective across all thistles, but different herbicides have higher efficacies based on the type. For example, Cimaron MAX is only 80-84% effective on Canada thistle compared to 90-95% effective on Scotch Thistle, so check an efficacy table and your fields before making herbicide choices.
Efficacy ratings show that ForeFront, Milestone, Chaparral, Grazon P&D, Stinger, and Tordon 22K consistently have an 85-95% control response across various thistles. When using Tordon 22K or Grazon P&D use extreme caution around other vegetation, especially trees. Both products will kill woody plants. Other products that have good efficacy are 2,4-D mixed with Banvel or dicamba, but should be sprayed when temperatures are warmer for the highest efficacy. Also Cimaron MAX, Distinct, and Overdrive all consistently have 80-90% control response across various thistles.
Bottom line: if you had thistles this summer and are relying on chemical control, spraying in the fall has more options for control.
SAMPLE AND TEST HAY
Do you know the quality of the hay or silage that you harvested this past season? It is important to know how much protein and energy your cows will get when you start feeding, or how much supplement to feed. Find out by following instructions for sampling and testing.
Correct sampling techniques, followed by lab tests of forage quality, are necessary for cattle producers who want to get the most value from their forages and profit from their animals.
Maybe the most important step in sampling hay, and sometimes the most difficult step, 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.
Obviously, the place to start grouping is to separate different types of hay, like alfalfa or CRP or corn stalk 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? The hay made without rain damage probably 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 and only then are you ready to sample. From each group gather a dozen or more 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 1 foot of the bale.
Finally, send these samples to a certified lab for tests of crude protein, energy content and possibly nitrates, if it was an annual forage and had some of the risk factors associated with nitrates.
Then use this information to feed your cattle as profitably as possible.
Cover crops can provide great fall and early winter forage for grazing before killing frosts stop growth. After the cover crop winter freezes, turns brown, and does not look “good” is it still good quality?
Oats and brassicas planted in late summer and early fall will change in quality from October through January, but it might be less than we would expect. With an oat and brassica mix the plants will likely die in the late fall after several hard-freezing temperature events. Growing oats will have 60 to 75% Total Digestible Nutrients and have 12 to 20% Crude Protein. Turnips and other brassicas will have a 70 to 80% TDN and 14 to 22% CP. This makes great grazing for any class of livestock.
A study at the University of Nebraska Lincoln looked at forage quality of stockpiled oats and brassicas progressing from fall growth into the winter. The mix was planted early September and late August in southern Nebraska. After the forage had died it was sampled again, in mid-January. The oats still had 15% CP and between 61 and 71% TDN. The entire brassica plants were 72% TDN and 14-24% CP and the leaves alone were 25% CP.
At this point in the year, planting a fall forage crop may not produce much due to the low number of growing degree days left. However, the point to consider is if there is some growth potential, stockpiling or deferring grazing will maximize production without sacrificing very much quality.
To review: Oats and brassicas maintain forage quality well into the winter. This allows to defer grazing to have more quantity and still high quality. ❖
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