Solar shade is the name, sustainability is the game and clean energy is the aim. With the beef industry facing continuous pressure from environmentalists and heat stress in feedlot cattle incurring great financial losses annually, producers are seeking inventive ways to simultaneously improve animal health and decrease high electricity costs.
Several studies have been conducted in recent years to evaluate the negative impact of heat stress during the summer months on the productivity and well-being of feedlot cattle. Increasing discussion has also increased about providing shade as a mitigation strategy. In general, the informal and formal results of these studies have shown an improvement in daily gain and carcass quality, decreased respiration rate and altered behavior.
Solartron Dual Axis Solar Shade structures
If adequate natural shade trees are not available, permanent or portable shade structures can be constructed. Current recommendations for design of shade structures are to use shade cloth that blocks a minimum of 80 percent of sunlight.
- The size of the shade structure should be such that stocker calves weighing 400 pounds have 15 to 20 square feet of shade per head; calves weighing 800 pounds have 20 to 25 square feet of shade per head; and cows have 30 to 40 square feet of shade per head.
- Two recent studies at Louisiana State University and Missouri State University have compared the performance of growing heifers provided either artificial shade structures with 80 percent shade cloth or natural shade trees.
- In the Louisiana State University study, 700-pound heifers were provided 37 square feet per heifer of artificial shade and 42 square feet per heifer of natural shade. Heifers provided natural shade tended to gain 0.20 pounds a day more than heifers provided artificial shade.
- In the Missouri State University study, 550-pound heifers were provided 28 square feet per heifer of artificial shade or abundant natural shade. Heifers provided natural shade gained 0.22 pounds a day more than heifers provided artificial shade.
- A University of Arkansas study found that beef cows provided natural shade gained 0.53 pounds a day more than those provided artificial shade. Based on these studies, current recommendations for design of artificial shade, although better than no shade, may not be sufficient to allow similar animal performance as natural shade.
Previous research has evaluated several aspects of designing shade structures such as roof material, percent of sunlight reflected and height of the shade. When given the choice, cattle prefer shade that blocks greater than 50 percent of sunlight
What’s shade got to do with it?
One solution – solar panels.
Dr. Brad Heins, associate professor of dairy management at the University of Minnesota and researcher at the West Central Research and Outreach Center in Morris, Minnesota, implemented this idea at the center’s 300-cow pasture to provide shade for the herd and energy to power milking equipment. “The concept of solar grazing started because we wanted to reduce heat stress and produce energy to utilize in our dairy farm,” Heins says. “Our goal is to have a net-zero dairy.”
Heins’ research study on the use of photovoltaic systems to shade grazing cattle evaluated four groups of cows during four periods of the summer. Two groups had access to solar panel shade and two groups had no access to shade. The results showed that shaded cows had lower respiration rates and body temperatures during afternoon hours than non-shaded cows. Heat stress reduction is not the only benefit of solar panel use. “We have also been able to produce about 4 megawatts per year to power lighting, equipment and other facilities we use on a daily basis,” Heins says.
Beef producers can parallel the dairy industry’s agrivoltaic development by implementing solar shade in feedlots, which often have limited cover for cattle. Nebraska entrepreneur, Mitch Minarick, has done just that. His Ag tech company, FarmAfield, is an online marketplace that connects consumers who want to invest in agriculture to farmers who raise the product, and the benefits of its solar panel research are three-fold: shade for feeder cattle, energy for producers and an environmentally friendly impact consumers can support
The cattle will seek out the shade, allowing the operator to better manage the location of the manure and proximity to the feed and water.
Space and location
Cattle will rest under the shade during the day and the shade should be 20 square feet per head. It should be located close to the feed bunk and water supply so that the cattle will be easy to observe and limit exercise on hot days.
This area will receive more waste accumulation making it cooler with the evaporation but should also be in a convenient location to box scrape on a regular basis.
Solartron – Construction and management
The considerations when constructing the shade are going to be building it high enough so that all equipment can pass under it with sufficient clearance. Our trackers at lowest inclination are more than 8-feet above ground level. Our single pier mountings are 3-foot diameter concrete which will have not affect from cattle bumping or rubbing against the supports. These supports are typically 80-90 feet or more apart for each solar tracking system so cattle are not crowded or interfered with during operations.
- Posts and poles need to withstand the rubbing of the cattle and the equipment bumping it.
- If you have specific questions call your extension and outreach beef specialist or agricultural engineer.
—From Iowa State University Extension e-newsletter Growing Beef, Vol. 3, Issue 12, June 201
Grazing Advantages of solar shading
Higgins and co-author Elnaz Hassanpour Adeh had previously published research showing that solar panels increase agricultural production on dry, un-irrigated farmland. They found that the grasses growing in shaded areas under the solar panels were 328% more water efficient and maintained higher soil moisture throughout the heat of summer. The result was twice as much grass under the panels as elsewhere in the pasture and that grass was much more nutritious.