Saline water intake effects performance, digestibility, nitrogen and water balance of feedlot lambs

Abstract

Context Water availability is often a limiting factor for herds in the arid and semiarid regions worldwide. Aim The present study aimed to evaluate the productive performance and nutritional status of Santa Inês sheep receiving water containing different levels of salinity. Methods Thirty-two intact Santa Inês lambs, with an average bodyweight of 21.76 ± 1.25 kg, were distributed in a completely randomised design with four treatments (concentrations of total dissolved solids (TDS) in the drinking water: 640, 3200, 5760 and 8320 mg/L TDS), and eight animals per treatment. Intake, apparent nutrient digestibility, water balance, nitrogen balance, and performance of animals were evaluated. Key results Concentrations of TDS in water promoted an increasing linear effect for water intake offered via drinking trough (P = 0.01), total water intake (P = 0.02), total urine excretion (P = 0.02), total water excretion via urine (P = 0.01), water excretion via faeces (P = 0.04), total water excretion (P = 0.01), absorbed water (P = 0.02), total nitrogen intake (P = 0.04), and water intake to total weight gain ratio (P = 0.01). No effect of increasing TDS concentration was observed for intake of dry matter and nutritional fractions, nutrient digestibility, water intake via food, total faeces excretion, water balance, nitrogen excretion via faeces, nitrogen excretion via urine, total nitrogen excretion, absorbed nitrogen and nitrogen balance (P > 0.05). No difference was observed in the performance of Santa Inês sheep consuming water with TDS concentration up to 8320 mg/L, which presented a daily mean weight gain of 0.105 kg/day. Conclusions Water with a concentration of TDS of up to 8320 mg/L can be used as drinking water for Santa Inês sheep. Implications Therefore, the water from wells, which is usually saline, may be an alternative to supplying small ruminants.