ISSUE FOCUS FEED & ADDITIVE MAGAZINE June 2023 29 Farm economics are also affected. Estimates of heat stress loss for the U.S. swine business alone total nearly US$1 billion. The magnitude of the loss heat stress imposes depends on how quickly the animals recover or the capability of the animal to respond to stressors. Producers can also play a role in managing heat stress by implementing a holistic approach that includes feed, farm and health management practices. Reducing animal density, feeding livestock during cooler parts of the day, adjusting nutritional density and providing colder drinker water are some examples of feed, farm and health adjustments that can help support animals exposed to risk of heat stress. NUTRITIONAL INTERVENTION TO DEFEND AGAINST HEAT STRESS Nutritional interventions represent a practical and cost-effective opportunity to reduce the negative effects of heat stress and improve animal productivity. Precision nutrition allows diets to be formulated in a manner that reduces internal metabolic heat generation. Increasing the levels of dietary fat and reducing the amount of crude protein or crude fiber is one example of tailoring the formulation to reduce metabolic heat generation. Compared to other feed ingredients, dietary fat generates less heat. In contrast, the fermentation of fiber and excess protein are associated with heat generation. Feed additives that supply antioxidants, osmolytes or gut health should be considered to support animals subjected to heat stress. Selecting trace minerals that are more bioavailable could potentially ameliorate production losses as well. HOW MINERALS SUPPORT PRODUCTION DURING HEAT STRESS Trace minerals are essential for maintaining animal health and production. The animal’s need for an immunological response during heat stress leads to an increase in its relative trace mineral requirements . Zinc, for example, plays an important role in the immune response, acting as a cofactor of many essential enzymes. It can also increase the expression of tight junction proteins in the gut, supporting gut integrity. Copper, much like zinc, acts as a cofactor in enzyme function and can affect microbial populations in the gut, thereby supporting proper gut functioning. Due to the effects of these trace minerals in the animal, they are a key factor to focus on during formulation, especially in cases of heat stress. Trace mineral contents in raw materials are generally low and they suffer from unpredictable availability. When selecting the right source of mineral to add to
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