Sensitivity of ponies to sodium in the drinking water

Abstract

Horses lose high amounts of Na through excessive sweating. These fluid losses can often not be replaced completely by voluntary water intake, requiring saline solutions as rehydration therapy to regain electrolyte balance. The experiment aimed to evaluate the sensitivity and tolerance of Shetland ponies towards different Na concentrations in their drinking water and contained three phases: (1) control: only fresh water provided; (2) pairwise‐preference test: choice between fresh water and saline solution with stepwise increasing sodium chloride (NaCl) concentration (0.25%, 0.5%, 0.75%, 1.0%, 1.25%, or 1.5%); and (3) free‐choice test: six simultaneously provided buckets containing NaCl concentrations of 0%, 0.25%, 0.5%, 0.75%, 1.0%, or 1.25%. During the pairwise test, the ponies did not distinguish between fresh and 0.25% NaCl‐water but demonstrated clear preference for 0.5%, whereas >0.75% NaCl was avoided/rejected. During the free‐choice test, a pronounced preference of fresh over saline water was exhibited. The Na intake via salt lick was not reduced as response to higher Na intakes via water. The ponies exhibited a remarkable sensory discrimination capacity to detect different NaCl concentrations in their drinking water. The acceptance of solutions with low NaCl levels (0.25/0.5%) without adverse effects demonstrates potential as rehydration solution for voluntary intake.

Tränkwasserversorgung bei Pferden – Was ist zu beachten?

“…Wurde eine Konzentration über 0,75% eingesetzt, wurde diese Lösung von den Tieren wieder schlechter aufgenommen. Ein anschließender Test mit freier Auswahl zwischen verschiedenen Konzentrationen von gelöstem Kochsalz und unbehandeltem Wasser ergab, dass die Tiere eine klare Präferenz für das nicht mit Kochsalz versetzte Wasser hatten, allerdings auch relevante Mengen der 0,25%igen Lösung aufnahmen 15 . Das Einmischen von Salz in die Ration liefert keine eindeutigen Ergebnisse in Bezug auf eine erhöhte Wasseraufnahme.…”