Tuesday, August 7, 2012

Drought-Related Issues in Forage, Silage and Baleage

The extreme drought of 2012 in the Midwest region has forced livestock producers to be concerned with drought effects such as high levels of nitrates in forage and drought-damaged crops for silage and baleage. Many producers are now searching for alternative feeding options for livestock. In addition to safety and herd health issues, these factors affect the business decisions for each operation.

In response to producers’ concerns, University of Missouri Extension has developed this list of producers’ questions answered by extension crop and forage specialists.

Drought issues related to feeding livestock

What amount of nitrogen or manure applied to hay is likely to cause a nitrate toxicity problem?
The more nitrogen supplied to the crop, the more likely nitrate toxicity will occur. Hay fields fertilized with nitrogen at rates of 75 pounds per acre or less typically have tested in the safe range this year.

Are the nitrates in forage substantially higher in the morning than in the afternoon?

If we get some rain, what happens to nitrate levels in corn?
Initially, nitrate levels will increase for a few days following a rain. However, nitrate levels will decrease to normal levels about 10 days after a rain if the crop begins to grow again.

After doing a nitrate quick test of feed sources, when should a farmer consider sending in a sample for a quantitative test?
If a nitrate quick test shows any reaction at all, a quantitative test (need to explain what quantitative test is) of the feed should be done before feeding it to livestock.

Silage and baling
How does feeding value of drought-damaged corn silage compare to that of traditional corn silage?
Because drought-damaged corn usually has less grain, its feeding value is lower than corn produced in a normal season. However, the ratio of grain to fodder in the silage does not change as much as is often anticipated. Typically, the feeding value is about 85 percent of that of normal corn silage feeding value.

Will nitrate levels in corn silage drop during the ensiling process?
Yes, typically nitrate levels drop 25 percent during the ensiling process if the silage ferments well.

Do nitrate levels in bagged corn silage get lower like nitrate levels of silage in a pit?
As long as the silage ferments properly, nitrate levels in bagged corn silage do not get lower.

Can drought-damaged corn be made into baleage (large round-bale silage)?
Yes, but it takes a bit of extra management. Be sure that the bales are compacted well, net wrapped (which keeps the stalks from poking though as much) and then wrapped with plastic to a final thickness of 6 to 8 mil. Corn should be baled at moisture content of 50 to 60 percent.

Will chopping silage at a higher level than usual, such as one foot high, lower the nitrate danger enough to make it safe for feeding?
Not necessarily. Nitrate concentrations are higher in the lower parts of the plant. Increasing cutting height can help lower the concentrations in the silage, but it does not guarantee that the nitrate levels in the feed will be safe.

What can I plant into dead or dormant cool-season perennial grasses that could provide winter grazing IF there is no rain in time to simulate a fall grass growth before the late October growing decline?
If it doesn’t rain until late October, there is nothing you can plant for winter grazing this year. If the drought kills a pasture, you could plant winter wheat or rye in late summer (early September), providing there is sufficient autumn moisture for establishment and growth.

What are some fall grazing forage options to plant if the drought “breaks” between now and mid-August?
See the previous answer. Winter annuals are the best.

My hay meadow received a rain shower last week. A lot of Johnsongrass has started to regrow in the meadow. If I cut it, will the nitrates persist in the hay?
Yes. The nitrates will not degrade unless you ensile the forage.

At what level of applied nitrogen or animal manure should I be concerned about the potential nitrate level in hay? Will it be the same issue in a pasture?
The levels are the same for pasture and hay. Any concentration above 0.25 percent can begin to cause problems, with concentrations above 1 percent causing the most serious problems. See MU guide G4661, Warm Season Annual Forage Crops for more information.

Will nitrate levels go down after hay is stored for a specific period of time?

What is the nutritional value of grasses or weeds — Switchgrass and foxtail in particular — that are still green at this time of year?
The nutritive value of forage is related to its stage of maturity. Typically, switchgrass and the summer annual weeds such as foxtail, barnyardgrass, goosegrass and crabgrass are reproductive this time of year; as such, they are “stemmy” and have low digestibility. But they can provide some roughage.

What are some alternatives for feeding hay?
Corn silage

Among alternative feedstuffs, high-nitrate corn silage is more readily available and offers the greatest energy content with the benefit of nitrate reduction. Corn silage necessitates that you modify your storage and feeding systems due to the wet nature of feed. If you make corn silage in bale form, you can use existing feeding and storage systems; however, waste will be higher than normal silage systems due to stalk refusal. If excessive dry-down occurred before the traditional corn silage harvest, baling wet stalks can lengthen the harvest window. Field reports indicate ear losses can be high with roller conditioners.

Corn stalks
Baling dry corn stalks after harvest can ensure accurate corn harvest estimates and increased nitrate-reduction time. Corn stalk grazing can limit field losses and waste hauling from feeding areas. You will need to add protein supplements to corn stalks. Chemical treatments such as calcium oxide (CaO) or ammoniation can improve forage quality and digestibility. Refer to these websites for more information on CaO treatment.

Soybean baleage
Soybean baleage will help maintain leaves on the plant during harvest. Harvesting dry soybean hay will result in high leaf losses and reduced forage quality. Immature pods contribute to the energy content of soybean hay; and pod formation will be variable. Therefore, you should perform forage testing to determine feeding recommendations. A delayed harvest of soybeans without pods will result in reduced forage quality due to advancing maturity. Observe herbicide grazing and haying restrictions

Poultry litter
In areas where broilers or turkeys are fed, you can feed poultry litter to extend hay supply and reduce supplemental protein needs. Litter must be staked and allowed to heat prior to feeding; but after storage it can be used as a supplement to hay or as a substitute. See North Carolina University Extension’s publication, Deep Stacking Broiler Litter as a Feed for Beef Cattle.

Traditional corn- and soybean-based byproduct feeds likely will be more expensive and in short supply. Consider alternatives such as wheat, peanut and cotton products. Wheat straw can be chemically treated similar to corn stalks. Gin trash and peanut hay offer alternative roughage sources. Remember, peanut and cotton hulls serve primarily as fillers and have low energy value, so price your supplements based on nutrient values rather than price per ton. If the local corn crop develops aflotoxin later in the fall, beef producers may buy infected corn at a discount.
Planting winter annuals such as oats, cereal rye and annual ryegrass in late August may offer some relief; however, you will need a timely rain to justify additional input costs. Be wary of herbicide carryover due to drought conditions.

Use MU Extension’s byproduct feed page to shop for alternative feed ingredients.

Can feed additives help reduce nitrate feeding risk?
Ensiling is the best option to use for high-nitrate feeds. Over time, in cattle, sheep, goats and buffalo, rumen microbes will develop increasing tolerance to nitrates. The best feed additive is a low-nitrate feedstuff, which will dilute nitrates. Bova-Pro is a commercial bacterial culture that claims to allow greater nitrate forage feeding levels. Results of an experiment using Bova-Pro suggest that tolerance to nitrate was increased; however, impact on reproduction was not observed.

What are recommendations for grazing corn?
Avoid grazing corn seven to10 days following a rain, because nitrates will increase. Waste will be high with grazing. Waste may be advantageous since most products left in the field will be high-nitrate stalks. Limit access to new and old stalks to reduce waste and regrazing stalks respectively

I have enough hay, but I also have access to corn silage. Should I chop the silage?
Use local distressed crops if silage fits your feeding system; then consider marketing excess hay as an alternative enterprise. Conversely, use silage to retain calves and move to a different marketing window, or dry lot cows or calves on a custom basis.

When are nitrate levels in forage too high for feeding forage by itself or mixed with hay?

If you can't read the chart very well, click here to see the chart and full extension publication.

Are high nitrate levels a bigger concern in specific classes of livestock?
As indicated in Table 1, young and pregnant animals are most susceptible to nitrate toxicity. Usually seven to 10 days after exposure to high nitrate feeds, pregnant animals will abort due to lack of fetal oxygen. Young animals are susceptible to nitrate toxicosis because their fetal hemoglobin has an increased affinity for absorbing nitrates. As with many other nutritional disorders, aged or poorly conditioned animals are at increased risk compared to well-fed or heavily conditioned animals

What are the keys to weaning calves early?
Work with your local veterinarian to develop a vaccine plan. In general, plan to vaccinate for blackleg and respiratory diseases 3 to 4 weeks before weaning. Revaccinate at weaning and fenceline-wean the calves. Because early weaned calves have a low feed intake, be sure to feed them a nutrient-dense diet. You may need to increase the nutrient concentration in their feed to allow adequate energy and protein intake. Make sure your facilities fit smaller calves by checking the calves’ ability to reach water and feed. Offer high-quality hay in feed bunks where feed is offered. Until calves are bawled-out and bunk-broke, feed them multiple times a day to encourage intake and check for sick animals.

What steps should I should take to extend hay supply?
Early weaning will reduce cow forage intake by 0.4 to 0.7 pounds per hundredweight of cow body weight. This results in an average savings of 7 pounds of dry matter a day following weaning. This savings extends forage supplies while allowing cows greater time to build body condition before winter. After early weaning and 90 days following the start of the 60-day breeding season, pregnancy diagnose cows and sort cows into the following management groups to prioritize culling order and forage resources.
·         Age, disposition, condition or terminal-age culls
·         Young, old, thin open cows
·         Adequately conditioned open cows
·         Low-producing or short-bred cows
·         Young, old, thin pregnant cows
·         Adequately conditioned pregnant cows

By prioritizing the forage supply and culling early, you will enable productive cows to use the available resources efficiently. Consider limit-feeding cows to increase efficiency. Limit-feeding will reduce waste and focus resources on high-nutrient demand groups. As hay prices increase, the cost of waste and inefficiency also will increase. You can increase hay supplies by 25 to 50 percent, depending on current systems, by reducing hay waste through improved storage and feeding practices. If you are feeding cows daily supplements, consider adding monensin to the supplement. Ionophores have shown 10 percent reduction in maintenance energy requirements; and monensin, the only ionophore approved for beef cows, increased energy content of poor quality hay by 15 percent in recent research at Oklahoma State University.

Drought questions affecting farm business decisions

Should I sell livestock or buy hay?
Cows without pasture will consume half a ton of hay per month. Purchased grass hay will cost between $100 and $200 per ton from now until the spring of 2013. Inventory your hay and cow numbers to estimate the cost of carrying cows until next spring. Most producers will find heavy culling justified or unavoidable. Sell cows and buy needed forage as soon as possible to avoid markets where prices are driven by glut and scarcity. An online Hay Days Available Calculator from the Noble Foundation can help you estimate your hay needs.

What are the tax liabilities if I sell cattle?
If you sell breeding cattle in excess of normal annual sales due to drought, and restock within the next four years, you can avoid paying income tax on the sales because all Missouri counties are included in the USDA drought declaration. Read more on IRS code 1033. In addition, if you sell any kind of cattle above normal volumes, you can defer paying the income tax due for a year under IRS code 451(e).

Will harvesting my corn for silage impact crop insurance payments I receive?
Crop insurance indemnities are not affected by harvesting corn for silage. In fact, harvesting damaged corn as silage offers additional revenue to the farmer without reducing revenue from insurance. Farmers who planted corn for grain but now want to harvest it as silage can do so after their insurance adjuster gives them permission. The adjuster will visit the field under consideration and give an estimate of yield that insurance will pay on or mark a strip of the field to be left until harvest. This strip, when harvested, will represent the yields of the entire field. Indemnities will be paid based on this yield. Two major cautions:
·         Never do anything before you contact your insurance company and receive their permission to harvest as silage;
·         Harvesting corn as silage will not reduce your insurance indemnity.

For insurance, how do I estimate potential yield with the in-field variability across the board this year?
Estimating yield for insurance purposes is the responsibility and sole prerogative of the insurance company. They are obligated to estimate yields according to best scientific methods. But if you disagree with their estimate of yield, your option is to let the crop mature until harvest. The time it would take to challenge an insurance adjuster’s estimate of yield would likely drag on beyond the appropriate time to harvest as silage.

What is the value of drought-stressed corn made into silage?
Drought-stressed corn silage generally has a feeding value of 85 to 95 percent of normal corn silage if a check of nitrate levels indicates it is safe to feed. The cost of other feeds is reflected in MU Extension’s weekly update of the latest relative feeding value of good corn silage going into a beef ration.

What is corn silage worth relative to corn?
Pricing 35 percent dry matter drought-stressed corn silage may be roughly based on the price of a bushel of corn:
·         If standing in the field, silage is worth five times the estimated harvest-time net price of corn per bushel. Example: 5 x $7 per bushel = $35 per ton.
·         If chopped, delivered and packed in silo, silage is worth seven times the estimated harvest-time net price of corn per bushel. Example: 7 x $7 per bushel = $49 per ton.
·         If dropped in the bunk in front of an animal, silage is worth nine times the estimated harvest-time price of corn per bushel. Example: 9 x $7 per bushel = $63 per ton.
Moisture levels, yields and shrink can differ dramatically from expectations. For tools to arrive at situation-specific prices, see MU Extension’s Missouri Dairy Business Update.

How do I estimate corn silage yield?
If little or no grain is expected, a rough pre-harvest estimate of yield is that 1 ton of silage per acre can be obtained for each foot of plant height, excluding the tassel.

How much corn grain should there be to justify combining the corn instead of chopping it?
The easy answer is to divide the cost of harvest by the market price. For example, if harvesting 1 acre of corn costs $30 and the market price of corn grain is $7.50 then a yield of 4 bushels per acre would pay for harvest.

However, corn yields of less than 30 bushels per acre may be difficult to harvest. A bushel of corn with normal-sized seeds contains about 73,000 kernels. If you assume a stand of 26,000 plants per acre and that each plant produces one ear, then it takes 2.8 kernels per ear to produce a bushel. So, a yield of 4 bushels per acre means the average kernel number per ear is 11. Even a yield of 30 bushels per acre translates into average ear size of 84 kernels — much smaller than the normal 600. Combines were not designed to efficiently harvest and shell such small ears, which are easily lost through the gathering mechanisms. Oddly shaped cobs and kernels may not flow normally through the rest of the combine. Kernels from sparsely populated ears can be larger than normal or much smaller than normal. If drought is relieved soon, then kernels will expand greater than normal and their shapes will be round because they do not have neighboring kernels to restrain their growth. If drought continues through seed filling, then seeds will remain small. Either of these abnormal kernels sizes may not thrash well from the cob. Smaller-than-normal kernels will have low test weights because they will contain relatively less starch and more cellulose.

So, low yield corn is difficult to combine, and increased harvest loss needs to be included in any calculations. Combine operators will need to pay special attention to machine settings. Unfortunately, wide variations for yield among areas in fields may make proper setting of combines difficult.

By University of Missouri Extension State Specialists
Joe Horner, agricultural economics specialist
Robert Kallenbach, forage production and management specialist
Craig Roberts, agronomy specialist
Justin Sexten, beef nutrition specialist
Laura Sweets, plant pathologist
William Wiebold, agronomy specialist

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