In a research article entitled: “Shade Options for Grazing Cattle” University of Kentucky Researchers had the following conclusions:
Shade is a must for pasture-based grazing systems. It curtails heat stress, which is detrimental to cattle and causes a decrease in milk production, feed intake, weight gains, and fertility. Heat stress is made worse in Kentucky and other humid parts of the eastern United States by the endophytic fungi that infect tall fescue, which is one of the most widely grown pasture grasses in
the region. It’s estimated that up to 95% of tall fescue pastures are infected with endophytes. Cattle grazing endophyte infected pastures experience increased body temperatures, largely from their inability to effectively transfer heat from their skin by sweating.
See the article at: AEN-99: Shade Options for Grazing Cattle