North Dakota University Explained

Heat Stress a Problem, Even for Northern Plains Cattle
High heat can take its toll on cattle. Heat stress can be a serious hazard for cattle, even in northern Great Plains climates.

The past week’s extremely hot and humid weather conditions have resulted in some reports of heat stress problems in beef cattle, particularly from feedlot operations in regions where the weather has been especially humid.

Cows and nursing calves are less susceptible but also can be affected by the high temperatures, says Greg Lardy, the North Dakota State University Extension Service’s beef cattle specialist.

Symptoms of heat stress include rapid breathing or panting, increased body temperatures, drooling, salivation or foaming at the mouth. Cattle will tend to stand grouped together during the early onset of heat stress. In severe cases, cattle will breathe with their mouth open and stand with their tongues protruding from their mouth. Along with the heavy, rapid breathing, cattle will appear to be pushing from their flanks. In the latter stages of severe heat stress, cattle will stand with their head down and may be away from the herd.

Heat stress usually is more severe when nighttime temperatures do not cool. Night cooling allows animals a chance to dissipate excess body heat that built during the day.

Lardy says solutions for combating heat stress include:

Changing the cattle’s feeding time from morning to late afternoon or evening Sprinkling the animals with water Providing shade Changing the feeding time shifts the heat produced during fermentation to night, a when cattle are better able to dissipate the heat.

Sprinkling usually is the most immediate solution. It should begin in the morning prior to the heat of the day. Producers should sprinkle the cattle and the mounds or surfaces of the pen where they lie.

“Providing shade will also help,” Lardy says. “However, this is a longer-term investment and is generally not something which can be done immediately.”

Dark or black-hided cattle are more susceptible to heat stress because their coat color absorbs more solar radiation; however, cattle of all hide colors can succumb to heat-related stressors and suffer from heat stress. In addition, cattle nearing market weight and carrying the most body fat or condition also are more susceptible because they are less able to dissipate excess body heat due to their fat cover.

Water requirements also increase dramatically during heat stress. In some cases, producers may need to add water spaces to provide the extra water cattle need.

Lardy recommends producers refrain from processing, moving or working cattle when ambient temperatures are high or heat stress is a potential problem.

“Working cattle in the early morning hours or waiting for relief from the heat wave is the best option,” he says.

Producers also should use fly control to provide cattle relief from the pests during periods of high temperatures.



Red Sunflower Seed Weevil
The red sunflower weevil emergence peaks in late July. There have already been reports of high numbers in eastern Ward County. Female weevils deposit eggs inside developing pericarp (sunflower shell) then larva feed on the developing seed. Start scouting as ray flowers are beginning to show, and continue until 70% pollen shed when sunflowers are no longer susceptible to damage. The red sunflower weevil is a rusty red color, about ¼” long, with a long snout, or proboscis. Economic thresholds are roughly 3-5 weevils per head, although as market prices increase that threshold may be lower. NDSU recommends treatment when 30% of plants are just starting to shed pollen. Control levels decrease after most of the plants are past 40% pollen shed. For more information refer to the 2007 Field Crop Insect Management Guide.

Now What’s Eating the Sunflowers?
Sunflower maggot has been reported in several fields in the north central region recently. It can be found by prying open the sunflower bud; dark brown spots on immature disk flowers may be observed. The larvae are less than ¼” at maturity. The small, brown pupae are found in the face of the sunflower bud, usually surrounded by a small number of damaged disk flowers. Adults of sunflower seed maggot have brown lace‑like wings, and emerge during the first week of July and lay eggs on the corolla of incompletely opened sunflower inflorescences. The total larval period is 14 days. The first generation pupates in the head; the second generation overwinters in the soil as pupae. Economic damage from the maggot is rare. The magnitude of damage to sunflower seeds by sunflower seed maggot larvae largely depends on the larval stage and seed development. Seed sterility occurs when newly hatched larvae tunnel into the corolla of young blooms; a single larva feeding on young flowers will tunnel through 12 ovaries. Mature larvae feeding on older sunflower heads destroy only one to three seeds. Since economic damage is rare, there is no research on control of the adult, and control of the larva is impossible as it feeds inside the bud and would be untouched by an insecticide application.



Can we successfully straight combine Canola?????
Current North Dakota State University Extension recommendations and guidelines for canola is to swath at the optimum stage to reduce green seed and seed shatter losses. From 2004-2006 there have been a number of small scale and field scale studies comparing straight combining canola with traditional methods of swathing and combining. The results of this research indicate that canola can be successfully straight combined. All combine headers: rigid, flex, and draper all performed well with straight combining canola and did not cause any harvest loss compared to the pick-up head. When harvested at the optimum time, straight combining canola can be successful with equal to higher yield than traditional harvest methods of swathing and combing. There is also less green seed and generally higher oil content and test weight with straight combining verses swathing and combining. One important consideration with straight combining is that it is more vulnerable to seed and shatter loss when harvest is delayed past the optimum. It is very important when straight combining canola to harvest at the optimum time and does not allow the flexibility of swathed canola. The optimum harvest time is identified at the first time the harvest moisture fall below ten percent. Research indicates that seed loss due to shatter increases significantly approximately 10 days after the optimum harvest time was reached.

NDSU Extension Service, North Dakota State University of Agriculture and Applied Science, and U.S. Department of Agriculture cooperating. Duane Hauck, Director, Fargo, North Dakota. Distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. We offer our programs and facilities to all persons regardless of race, color, national origin, religion, sex, handicap, age. Vietnam era veterans status, or sexual orientation; and are an equal opportunity employer.

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