Ag Connection

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Volume 4, Number 8
August 1998
This Month in Ag Connection

Extend the Grazing Season with Brassicas
Double Cropping Fescue
The Good, the Bad and the Toxic - Blister Beetles
Not All Balage Is Created Equal

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Extend the Grazing Season with Brassicas

Don’t want to eat your turnip greens even though you know they are good for you? Feed them to your grazing animals. Turnips are just one example of the brassica family that include turnips, rape, kale, and swedes. They are very fast growing, highly nutritious, and can provide grazing 70 to 90 days after seeding. Depending upon the type of brassica and plant part, protein values range from 14-24% and can have exceptionally high digestibility values of 85-95%. Weight gains for stocker cattle grazing brassicas have been reported at 1.5 to 2.0 pounds/day.

With this high quality comes a drawback. Quality this high corresponds to very low fiber content of the forage. This can result in an extremely fast rate of passage through the rumen leading to incomplete digestion. Simply stated, the animal may not get the benefit of the high protein and high energy content. Brassicas should then comprise not more than two thirds of the forage portion of the diet. The remainder could be hay or other grass pasture. Brassicas also contain glucosinolates which can interfere with the animals’ uptake of Iodine. This is especially critical for sheep and goats. Brassicas also have a higher than desired Ca:P ratio along with high levels of K. This can interfere with magnesium availability in grazing animals. They also can be nitrate accumulators when fertilized with high levels of N. These potential animal problems can be avoided though mineral supplementation and controlling the intake of brassicas.

These crops have been used for years in Europe and other parts of the world very successfully for livestock feed, but they have not gained much popularity here in the U.S. These crops can survive light freezes, which make them ideal to extend the fall and early winter grazing periods.

Seeding for fall grazing should be done by mid-August. Brassicas may be no-tilled into sod, providing the sod growth is controlled or conventionally tilled into prepared seed beds. Seeding depth is to inches deep in a firm, well-drained seedbed. A starter fertilizer should be applied at seeding that supplies a nitrogen boost to seedlings. Seeding rates will vary, depending on brassica, from 2 to 4.5 pounds of live seed per acre.

Greatest utilization of these forages will come from some type of controlled grazing to reduce the amount of soiling and trampling of the forage. This will also allow for regrowth of the forage and extension of the grazing season.

While little research has been done on brassicas for forage in Missouri, they have potential to complement our grazing systems and could work very well with stockpiled tall fescue for fall grazing. Another possible problem with these plants is their potential as weeds. (James Rogers, Livestock Specialist)

Author: James Rogers, Livestock Specialist


MU Guides for more information:

G4670 - Seed Production of Tall Fescue and Other Cool Season Grasses

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Double Cropping Fescue

Wait a minute — isn’t fescue a perennial crop and a forage? Where could the idea of double cropping come from? Fescue is not only harvested or pastured for forage but also is used as a seed crop. It essentially makes the fescue seed an easy value-added crop. Frequently, harvesting fescue seed is a last minute decision. If the seed crop looks good for a particular year, a farmer says to himself "let’s combine the fescue and sell the seed." Other fescue producers are thinking the same thing. The result is a low price for the seed.

A better approach is to plan for both forage and seed production on a long term basis. If seed was the primary or only commodity, the fescue would be grown in rows like corn, soybeans or wheat. Realistically, forage is the primary crop. The management needs to be such that a respectable seed crop is also produced on a regular basis.

The first thing to do is take a soil test. Nutrient availability is a critical factor in forage and seed production. It is controlled by soil pH and the amount of nutrients in the soil. A soil pH of 5.5 or above needs to be maintained. If lime is needed, it should be applied as soon as possible to allow for activation in the soil.

Nitrogen is primarily responsible for how well the seed heads fill. Phosphorous and potassium should be maintained at medium to high levels for better tillering.

The timing of fertilizer applications must be considered. For seed production, late summer or early fall are best for the P and K applications. To accomplish both fall stockpiling and seed production, the nitrogen will need to be split into two applications — an August application for stockpiling forage and a December or January application for the seed. Late summer nitrogen applications of 30 to 40 pounds/acre benefit the growth for fall stockpiling, but that nitrogen will be gone by the time it is most needed for seed production. A winter application of 70 to 100 pounds for seed production may surprise most fescue farmers. Fescue seed production is comparable to other grain production and fertility must be managed accordingly. February or later nitrogen applications are too late and can cause lodging or vegetative growth — not larger seed heads.

Another important practice for maximizing the number of seeds produced is clipping the fescue stubble to 3 to 4 inches right after seed harvest or seed maturity. Clipping allows the sun to penetrate to the crowns, stimulating tillering. The more tillers produced, the more seed heads. Removing the residue may increase light penetration. This residue is not a very high quality forage but could be improved by ammoniation. Leaving the fescue unclipped could reduce seed production as much as 30 percent.

Grazing in August, September and October should not be too heavy, but should be increased in November so all growth is removed by January 15. Cattle should be removed from seed fields by around the third week of March or many of the potential seed heads will be grazed.

If the fescue seed is to be combined directly instead of mowed and windrowed, harvest delays can reduce yields by 50 percent or more. Begin direct harvest when 5 to 15 percent of the seeds are immature. Harvesting when more of the seeds are still immature results in low yields and high moisture seed. Set the combine according to the manufacture’s recommendations, but watch the chaff for excessive seed loss and adjust accordingly.

Contacting seed buyers just before harvest can provide timely hints on harvest and handling. Even properly harvested seed should be cleaned of green materials and dried. If dried in a bin, the seed should be stirred. Drying temperatures should not exceed 90 F.

Author: Jim Jarman, Agronomy Specialist


MU Guides for more information:

G5469 - Blister Beetle Management in Alfalfa

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The Good, the Bad and the Toxic

Blister beetles, or the "old fashion potato bugs" are a real mixture. Although mostly thought of as pests, blister beetle larvae are partially beneficial since they feed on grasshopper eggs.

Typically, in years when grasshoppers are numerous, blister beetles are numerous. Grasshoppers are numerous now, so we should expect to see plenty of blister beetles.

Adult blister beetles feed on a wide variety of garden, horticultural, crop and weed plants. If you find a water hemp or climbing milkweed stripped of leaves, it was probably done by blister beetles feeding in a swarm.

Their worst attribute is the toxic, blistering oil found in their blood. Cantharidin is the irritating toxin in blister beetles affecting the gastrointestinal and urinary tracts of horses. Typical symptoms of cantharidin horse poisoning include abnormal breathing patterns, mouth submerged in water for long periods of time (they may blow air into water) and restless behavior. Other symptoms may include blistering of the mouth, colic, pawing, frequent attempts to urinate, jerking contractions of the diaphragm, diarrhea, discarded intestinal tract lining in the stool, and reduced levels of calcium and magnesium in the blood.

Mower conditioners crush the blister beetles and they are baled in the hay. It takes about 50 to 100 beetles to kill a horse. Cattle and sheep are more tolerant and no deaths have been reported in Missouri (yet); however, they may exhibit symptoms if high numbers of beetles are consumed. Little is known about the effects on lactating dairy cows.

The toxin does not break down quickly. Infested hay will remain toxic for several years.

Stripped blister beetles are the most common ones found in Missouri and have yellow or orange stripes along the length of their body. Other common blister beetles are black, gray or black margined with gray. Blister beetles are about to 1 inch in length, have a dull or flat coloration, cylindrical bodies, and a roundish head.

There are several tips for blister beetle management in alfalfa that can reduce (unfortunately none will totally eliminate) the blister beetle problem.

(1) Use first cutting alfalfa as feed for horses. In most years, blister beetles will not emerge until after the first cutting of alfalfa has been harvested in Missouri.

(2) Control weeds and harvest alfalfa before flowering. Blister beetles are attracted to flowering weeds or blooming alfalfa. Weed-free alfalfa, if harvested before bloom, will be less likely to attract beetles into the hay field.

(3) If possible, avoid the use of hay conditioners or crimpers if blister beetles are present at harvest time. Blister beetles often congregate in large groups. Because of this behavior, conditioners or crimpers often kill large numbers of beetles in a small area. Using a self-propelled harvester with wide set wheels and no conditioner or crimper will prevent most beetles from being killed at the time of cutting and the living beetles will move out of the alfalfa as it dries. A sickle bar mower will do the same if the operator avoids driving on freshly cut hay.

(4) Thoroughly scout fields 7 or 8 days prior to harvest. If blister beetles are present, use Sevin (carbaryl). Check the label, your dealer, or local Extension Center for the suggested application rates. Carbaryl must be applied 7 days prior to grazing or cutting of alfalfa. The application should kill most blister beetles and allow them to drop to the ground and away from harvest equipment. Care should be taken not to pick up the dead beetles with equipment during the harvesting process. Read and follow all pesticide label precautions and restrictions.

(5) Check hay for the presence of blister beetles at the time of feeding. Dead blister beetles are readily preserved and often retain their shape in baled alfalfa. If present, do not feed infested hay to horses.

Remember — these actions will only decrease the risk of blister beetles being baled into the hay, not eliminate the risk.

Author: Jim Jarman, Agronomy Specialist, Wayne Bailey, UMC Entomologist; and Anastasia Becker, UMC Senior Research Specialist, Entomology

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Not All Balage Is Created Equal

Place and Heinrichs have the following suggestions on balage:

  1. Aim for 50 to 60 percent moisture when making balage.
  2. Monitor dry matter content as baling progresses.
  3. Wrap bales as soon as possible after baling to minimize exposure to the air.
  4. Get a good composite forage analysis for ration balancing.
  5. Strategically mow and bale the crop. Optimum moisture is critical to getting good balage. Remember that forage density will vary over the field. Time cutting and baling to obtain the optimum moisture content.
  6. To improve feed out consistency, store the bales by field and cutting.
  7. Feed balage free choice with another forage.
  8. Try to incorporate another forage in the ration.

The rural landscape is becoming increasingly dotted with rows of plastic wrapped big round bales (balage). Baling high moisture forage can increase operational efficiency and flexibility for the farm. For example — putting up wheatlage helps increase the chance of a successful follow-up crop of soybeans; and balage has enabled many farmers to harvest their forage crops between this spring s frequent rains. However, while the packages of plastic wrapped balage all look very uniform, research from Pennsylvania State University reveals substantial variation of dry matter and nutritional value from bale to bale, field to field, and farm to farm.

Pennsylvania dairy agent Nick Place and Arlyn Heinrichs, PSU dairy and animal scientist, studied the balage of five farms. Their study revealed wide variability in dry matter content and nutrients of the balage. The dry matter averaged 46.6% (40% to 50% is considered ideal) but ranged all the way from 23.2% to 85.5%.

Moisture at wrapping was reported as the key to producing high quality balage. Place and Heinrichs stated that wet bales are more likely to grow spore-forming clostridia bacteria during fermentation.

Dryer balage traps more oxygen, which uses more carbohydrates during fermentation and results in a higher pH, more volatile nitrogen levels and much less of the desirable lactic acid.

Further, the variation in dry matter content of balage can lead to problems dealing with varying dry matter intake and nutrient levels.

Author: Parman Green, Farm Business Management Specialist

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University of Missouri ExtensionAg Connection - August 1998 -- Revised: April 20, 2004