Effects of drinking saline water on food and water intake, blood and urine electrolytes and biochemical and haematological parameters in goats: a preliminary study

Abstract

Drinking-water availability, both of quantity and quality, critically limits animal farming in semiarid and arid areas, but differences among species exist. The aim of the present study was to investigate goat saline-water tolerance. A group of four castrated adult males were used in a 4-week experimental period, which followed a 2-week pre-trial period and preceded a 1-week post-trial period. Animals were offered alfalfa hay and concentrates at about maintenance level and were allowed consecutively the following five levels of water salinity: 0‰, 0.5‰, 5‰, 10‰ and 20‰ NaCl. Feed and water consumption were recorded daily during trial, while blood- and urine-sample collections were performed weekly. Plasma concentrations of aldosterone, sodium (Na), potassium (K), glucose, creatinine, urea and proteins, and haematological parameters were analysed. Furthermore, urine pH, specific weight and concentrations of Na, K and creatinine were measured, as well as plasma and urine osmolality. Water intake increased until 10‰ NaCl (from 2.0 to 3.2 L/day, P < 0.001) and decreased thereafter to reach 2.5 L/day. Feed intake decreased (from 1.4 to 1.1 kg/day, P < 0.001) and urine excretion increased with an increasing salinity (from 1.12 to 1.47 L/day, P < 0.001). Increasing salinity elevated plasma concentrations of Na (from 143 to 150 mmol/L, P < 0.05), glucose (from 67.50 to 80.75 mg/dL, P < 0.05), urea (from 26.5 to 47 mg/dL, P < 0.01), proteins (from 6.3 to 8.3 g/dL, P < 0.001), osmolality (from 284 to 299 mosm/kg, P < 0.01) and creatinine (from 0.8 to 1.0 mg/dL, P < 0.01) whereas, K, aldosterone and bodyweight remained unaffected. Moreover, urine osmolality (from 317 to 1217 mosm/kg, P < 0.001), specific weight (from 1018 to 1040, P < 0.01), Na (from 55 to 377 mmol/L, P < 0.001) and K (from 144 to 329 mmol/L, P < 0.001) increased, whereas, pH and creatinine were unaffected. Observed changes in other haematological parameters are considered of minor physiological importance. The results indicated that goats can subsist on drinking saline water (up to 20‰ NaCl), for at least 2 weeks without harmful effects.