Preference and discrimination behaviour of llamas to saline drinking water

•The sensitivity of llamas towards different NaCl concentrations in their drinking water was measured.•Llamas showed preference for saline water with low NaCl concentrations.•Rejection was observed in llamas for water with more than 1% NaCl.•Llamas differentiated between saline water concentrations and showed ability to adjust Na intake in self-selection. Global climate changes increase the risk of salinization of soil and water imposing possible health risks on livestock, especially in arid and semi-arid regions such as the Andes, the habitat of wild and domestic South American camelids (SAC), e.g. the llama (Lama glama). The aim of the present study was to evaluate the sensitivity and tolerance of llamas towards different NaCl concentrations in their drinking water. In total, 12 adult females with an average body weight (BW) of 140 kg ± 20.6 kg were kept under controlled conditions in individual pens. After a control phase (1 week) providing only fresh water, two choice tests were consecutively conducted: (1) a pairwise preference test (3 weeks) offering one bucket with fresh water and another with stepwise increasing NaCl concentration (0.25, 0.5, 0.75, 1.0, 1.25, 1.5 %) and (2) a free-choice test (3 weeks) during which six buckets were simultaneously offered with NaCl concentrations of 0, 0.25, 0.5, 0.75, 1.0, and 1.25 % NaCl. Chopped hay, water and a salt lick were provided for ad libitum intake. Records were kept on BW, body condition, feed, water and Na intake. Dry matter intake, total water and Na intakes increased during both choice tests (P < 0.001). Daily total Na intakes relative to metabolic body size (g/kg0.75) averaged 0.04 ± 0.02, 0.19 ± 0.02 and 0.26 ± 0.02 during the control phase, the preference and the free-choice test, respectively. In the pairwise test, llamas showed a weak preference for saline water with 0.5 – 0.75 % NaCl, and rejected water from 1.25 % NaCl. During the free-choice system, llamas had a remarkable interest in saline water with shares from total drinking water intake for fresh water and concentrations of 0.25, 0.50, 0.75, 1.0 and 1.25 % NaCl being 23.6, 21.2, 19.5, 13.8, 13.3 and 8.6 %, respectively. Llamas demonstrated a similar capacity to differentiate between saline water concentrations in two different experimental setups and adjusted their Na intake in self-selection. The results suggest that their reactions to saline water are similar to those of goat breeds adapted to arid zones.