ISSUE FOCUS 40 FEED & ADDITIVE MAGAZINE July 2023 The impact of heat stress on dairy cow health and performance can be devastating, but the solution can be simple: Minimize heat gain and maximize heat loss. You can achieve this with evaporative cooling strategies, ample amounts of cool, clear water and the right nutrition to replenish lost nutrients. Hot weather reduces feed intake and rumination, ultimately hampering milk production and reproductive performance. So, how do you protect your cows? By preparing them. PUT COWS IN A COOLING CYCLE Heat stress happens when the cow’s heat load is greater than her capacity to lose heat. When cows are hot, they pant and sweat, but neither is nearly effective enough to expel the large amounts of heat created by cows. The formula to alleviate heat stress is simple: soak, dry, repeat. Evaporative cooling is the most effective method for expelling heat from the cow. In this process, cows are soaked with water, then air movement over the cow creates an evaporative effect that pulls heat from the body, increasing cows’ natural evaporation rate to improve cooling. In the past, cows have stood for long periods of time under misters to get cool. That method has improved and the process now includes large droplets of water sprayed over the entire back of the cow long enough for water to get under the cow’s hair and to the skin. It’s important to create a cooling cycle that includes a soaking period followed by drying time. Create enough water volume to cover the cow in 30 seconds or less, timing it so about 80% of the cow dries before soaking again. To achieve this level of dryness in a short amount of time, it takes good air flow—and that requires fans. Adding a greater number of fans in the barn creates more consistent air flow on top of cows with fewer dead spots. Use fans with good spread and throw to get the best coverage and best return on evaporative cooling benefits. Technology at this stage also helps make the soaking process more efficient. Sensors can recognize if a cow is in a lockup and turn off the nozzle if no cow is present. Controllers can break the barn into quadrants and manage soaker times long enough to get cows soaked, then turn themselves off. They can also be set to turn off when no cows are present, such as when a pen is in the holding area. One common area where heat stress affects cows is the holding area. Cows can quickly spike high HELP DAIRY CATTLE BEAT THE HEAT FOR MAXIMUM PRODUCTIVITY Dr Ruby Wu Dairy Technical Services Manager Arm & Hammer Animal and Food Production
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