Ivan Rush: Treating low-quality forages
September 5, 2012
The drought hangs on, its grip tightening as time goes on, and fall is still a long ways away. It's difficult to write when there are no low-cost alternatives. Early weaning, which should be one of the first considerations, and alternative forages have already been discussed.
Fortunately there seems to be large quantities of wheat straw, going to states like Colorado that suffered from timber fires, for conserving and restoring timber areas. When prices are already high the last thing we need is government competing for cellulose that could be used for cattle or sheep. Wheat straw (and other low-quality roughages) are excellent when blended with wet distillers grains or syrup. However, with ethanol plants shutting down, less wet feeds will be available.
In previous drought years, treating wheat straw and other low-quality roughages with anhydrous ammonia has been met with success. But lately I've found very little interest in treating straw. This is probably due to cost for straw, treatment and labor.
When wheat straw is treated it has similar feed value to average quality grass hay. Wheat straw roughly has 4.5-5.0 percent protein and 40 percent TDN (or energy). After treatment it will have approximately 50 percent TDN and 8-9 percent crude protein. The increase in crude protein is all from the anhydrous ammonia which is not all utilized in the rumen. After treatment straw is much more palatable and be fed satisfactorily without grinding. It will have enough feed value to maintain a beef cow in the mid part of pregnancy.
There are several problems utilizing anhydrous ammonia. Among those are that it is a batch process, which takes labor for large quantities and the added cost (especially for anhydrous).
The process is fairly simple. Stack straw where the largest piece of plastic (usually 40-foot by 100-foot) can completely cover the pile so that the edges can be covered with soil. Place a small pipe under the plastic and add 3 percent anhydrous ammonia by weight per ton of straw. The fiber breakdown of the straw is much faster and more complete if the average outside temperature is 75-80 degrees F. or greater. It does work if temperatures are cooler but takes longer. For more detailed information on the entire process refer to UNL publication EC89-265 at http://digitalcommons.unl.edu/extensionhist/245/.
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If anhydrous costs $850 per ton, and plastic $280 for a 40-foot by 100-foot sheet, it would cost approximately $35 per ton plus labor to treat. This program is not for everyone, but can feed a group of cows in mid gestation fairly economically. If straw costs $100 per ton, plus $45 for treatment, a cow can be fed approximately 30 pounds per day, resulting in a daily cost close to $2.15 per day. This is still high, but is a figure for comparison purposes.
Another forage treatment on the horizon is treating low-quality forages with calcium hydroxide (CaO), which is sold in lumber yards as Quicklime and used primarily by masons. This treatment process shows promise as it can be a "flow" process and stored in bunked silos. The major disadvantage is that it appears to be most effective when mixed with water so the mixed feed is about 50 percent moisture.
UNL research utilized a batch mix/feeder box to get the exact mix of water and CaO. The mixture was stored in plastic silo bags for 30 days before feeding. Researchers treated both corn stalks and wheat straw and substituted in 20 percent of the treated material for cracked corn in finishing diets. Cattle fed treated low-quality feeds performed equally as well as cattle fed 20 percent cracked corn. Although this research was with finishing diets, increased performance is expected if fed to growing cattle or cows. For details on the finishing trial, read entire article at the http://digitalcommons.unl.edu/animalscinbcr/690/.
To my knowledge Quicklime is not available in bulk. I'm sure innovators with the ability to add water during the flow mixing process will find a way to mix the product economically.
County fairs in the region are in full swing. Plan to attend and support our next generation.