A study of parotid salivation in the horse

Abstract

1. Saliva flowed from the horse's parotid duct only during mastication. 2. The surface‐active local anaesthetic administered by mouth inhibited salivary secretion. 3. Salivary secretion was stimulated by pilocarpine and inhibited by atropine. 4. The volume and composition of saliva secreted in 24 hr from one parotid duct was determined. 5. The concentration of sodium, potassium, calcium, chloride and bicarbonate depended upon the rate of flow. The highest concentrations of these electrolytes were observed during periods of high flow rates. 6. Horse parotid saliva contained a high concentration of calcium. 7. In the absence of a dietary supplement of sodium bicarbonate, the sodium concentration of the saliva fell after about 21 days. There was an associated increase in the potassium concentration. The addition of a sodium supplement restored the sodium concentration of the saliva within 24 hr.

Effects of feeding different roughage-based diets on gastric mucosa after weaning in warmblood foals

“…Horses have a continuous gastric acid secretion of 1.5 l containing 40 to 60 mmol hydrochloric acid (HCL) per hour (Picavet 2002) but buffering saliva production starts only with feed intake (Alexander 1966). Due to the lack of a protective mucus layer, the non-glandular portion is vulnerable to a prolonged exposure to HCL.…”

Identification of metal residues associated with bit-use on prehistoric horse teeth by scanning electron microscopy with energy dispersive X-ray microanalysis

“…The specific characteristics of the oral environment could affect the corrosion of a bit. Horse saliva contains bicarbonate, which is alkaline and helps counteract the acid produced by the horse's stomach (Pilliner, 1992, 2), and pH values of 7.5 and 8.5e9.1 are reported from published studies on horse saliva (Alexander, 1966;Moeller et al, 2008). The abrasion of one material by another will depend on the relative qualities of the two materials (e.g.…”

The Effect of Diuretics on the Faecal Excretion of Water and Electrolytes in Horses

“…Sodium depletion in ponies reduced faecal sodium excretion to about 1/12 of that in replete animals (Alexander, 1966). It was assumed that, as in other species, this increased sodium retention was mediated through the increased secretion of aldosterone.…”

“…Usually about three weeks were required to produce sodium depletion by salivary drainage as indicated by the typical change in the sodium/potassium ratio in saliva (Alexander, 1966). Although sodium depletion stimulates aldosterone secretion and thus increases retention of this ion, recent work (Carey, Smith & Ortt, 1976) has shown that, in rabbits, sodium excretion may be controlled through the gastrointestinal tract independent of aldosterone.…”