By Emily Fread
It has been well established in the dairy industry that heat stress negatively affects all animals on the farm during the summer. Lactating cows experience fluctuations in fat and protein yields, as well as lowered milk production and dry matter intake. Heat stress in dry cows leads to shorter gestation lengths, challenging transition periods, and reduced production in the subsequent lactation. Heat stress in calves and heifers affects growth rates and disease. It is essential to provide heat abatement for all animals on the farm, regardless of age group or lactation stage. Heat abatement can be supplied in three ways: shade, air, and water.
Shade can be provided on pasture with trees or a shade structure. When shade is provided on pasture, it has been shown to decrease aggressive behaviors toward other animals and increase rumination, grazing, and resting time (Kendall et al., 2006; Vizzoto et al., 2015). Shade can also increase milk production when provided for lactating animals on pasture. There are several variables to consider when building shade structures: whether they will be permanent or movable, and the cost of materials. Some producers employing rotational grazing practices may want to move their shade from pasture to pasture. Many portable shade structures are built with a steel frame and can be pulled around pastures with equipment or are collapsible for easy transport. Mobile shade structures can be constructed with corrugated steel coverings or shade cloth. Shade cloths must be replaced every few years due to damage; corrugated steel may have a higher initial investment, but it lasts longer than shade cloth. When summer is over, consider what will happen to your shade structures over the winter. If your system includes a shade cloth, it can be ripped or damaged by the weight of snow, so the shade cloth should be removed, or the structure should be collapsed before winter weather. If shade structures are left on pasture over the winter, they should be inspected in the spring to assess any damage and need for replacement. Shade cloths should also be inspected at the end of the summer season to assess damage due to birds.
Source : psu.edu