Saline drinking water effect on physiological, metabolic, and productive performances of ruminants in arid and semi-arid regions: a systematic review

Abstract

Water scarcity and declining freshwater quality are growing challenges in livestock production, particularly in arid and semi-arid regions, where ruminants increasingly rely on brackish or saline water sources. This review synthesizes data from fifty-seven studies on the effects of drinking saline water (500–20,000 mg/L total dissolved solids (TDS)) on ruminants’ water intake, feed consumption, digestibility, nitrogen metabolism, blood biochemical parameters, production performance, physiological responses, behavior, and reproduction. The analysis indicates that moderate water salinity (>3,000–8,000 mg/L TDS) generally stimulates water intake through osmotic and endocrine mechanisms, whereas high salinity levels (>8,000 mg/L TDS) generally reduce palatability, alter rumen osmolarity, and reduce dry matter intake. These changes can subsequently affect body weight, rumen fermentation patterns, nutrient digestibility, and nitrogen utilization in a species- and age-dependent way. Alterations in blood metabolite, electrolyte, and enzyme activity reflect adaptive or stress-related physiological adjustments, particularly in renal and hepatic functions. Production responses, including milk yield and composition, growth performance, and meat quality, vary and depend on the salinity level, duration of exposure, animal category, and diet composition. Although limited, available evidence suggests that high salinity intake during gestation and lactation may indirectly compromise reproductive performance through reduced intake, metabolic stress, and endocrine dysregulation. Overall, ruminants exhibit considerable adaptability to saline water; however, their tolerance thresholds vary widely among species and physiological states. This review highlights critical knowledge gaps and emphasizes the need for well-controlled, long-term studies to establish safe salinity limits for sustainable ruminant production under water-limited conditions.