ISSUE FOCUS 44 FEED & ADDITIVE MAGAZINE July 2023 Animals experiencing heat stress lose body fluids (sweat) and need to control dehydration and blood homeostasis (Das et al., 2016). Heat challenges can also result in an altered endocrine status and changes in body composition (Rhoads et al., 2013). Reduced blood flow can limit cellular gut activity and may affect the gut’s ability to maintain barrier functions, such as mucous secretion. This barrier function is part of the cow’s defense system and is designed to prevent pathogens and toxins from entering the circulatory system. On a cellular level, heat stress is responsible for a number of molecular responses, and is linked to oxidative stress in livestock animals (Ganaie et al., 2013; Nizar et al., 2013), resulting in cytotoxicity in various forms, such as alteration of biological molecules, disturbance of cell functions, modulation of metabolic reactions, induction of oxidative cell damage and activation of apoptosis and necrosis pathways (Du et al., 2008; Pandey et al., 2012). An increase of the intestinal cells’ permeability also increases the cow’s inflammatory status and could potentially lead to sepsis. Thus, the more stress the animal is under, the more immunity is compromised. Removing excess body heat is essential to prevent the animal from entering a stage of hyperthermia. In addition, maintaining optimal temperatures for cows is a crucial condition for their high productivity and general health. ALLEVIATION STRATEGIES FOR DAIRY CATTLE Multiple approaches have been suggested to mitigate the impact of heat stress in dairy cattle, in- “Heat stress is one of the most significant stressors at a time when ever-changing climate conditions are impacting ruminants of all sizes, from sheep and goats to beef and dairy cattle. Multiple approaches have been suggested to mitigate the impact of heat stress in dairy cattle, including housing modifications, genetic selection for heat-tolerant cows and nutritional management."
RkJQdWJsaXNoZXIy MTUxNjkxNQ==