Outdoor-kept livestock require shelter from climatic extremes to maintain welfare. Inadequate shelter from rain, wind, sun, or cold causes thermal stress, reduced feed intake, poorer body condition, and increased susceptibility to disease. Providing appropriate shelter is both a welfare obligation and a practical management requirement.
Heat stress occurs when heat gain exceeds heat dissipation. For cattle, the threshold temperature-humidity index (THI) above which production is affected is approximately 68 (equivalent to approximately 21°C at moderate humidity). Shade provision in summer significantly reduces THI experienced by cattle. Natural shade (trees) is preferred and used more readily than artificial shade, but both are beneficial. Key factors: shade area per animal (minimum 4m² per cow; 1.5m² per sheep), orientation (east-west to minimise midday direct sun on animals in shade), and accessibility for all animals without competition.
Cold wind significantly increases effective temperature and energy demand. Livestock exposed to cold, wet, windy conditions without shelter show increased feed requirements (to maintain body temperature), poorer growth rates, and higher disease susceptibility. Hedgerows, tree belts, topographic features, and purpose-built windbreak structures all provide valuable shelter. Neonatal animals (calves, lambs, piglets) are particularly vulnerable to cold exposure.
UK welfare regulations (Welfare of Farmed Animals Regulations 2007) require that all farmed animals have appropriate shelter from adverse weather conditions. The specific provisions vary by species and system, but the underlying obligation is clear: outdoor-kept animals must have access to shelter that provides meaningful protection from climatic extremes.