The impact of heat stress on global ruminant livestock production and potential adaptation and mitigation interventions

Rising global temperatures and more frequent heat waves impose severe heat stress (HS) on ruminant livestock, threatening the sustainability of intensive and extensive production systems. This mini-review evaluates nutritional, genetic, and engineering (including nature-based) interventions designed to build livestock resilience within climate-smart food systems. HS limits feed intake, disrupts reproductive physiology and elevates disease risk. Climate modelling projections indicate that by 2050, millions of cattle, sheep, and goats will experience 10-20 additional extreme HS days annually, impacting animal welfare, and generating massive economic losses, particularly in low- and middle-income countries. Nutritional strategies such as betaine, organic selenium, polyphenols, and chromium reduce endogenous heat production, oxidative stress, and gut permeability, thereby maintaining performance under HS. Mitigating these impacts requires an integrated deployment of targeted nutritional supplements, genomic and indigenous selection for thermotolerance, and environmental modification. This mini-review provides a critical evaluation of these multi-faceted strategies, emphasising their inherent trade-offs, economic feasibility and resources limitations.