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Abstract
The salivary secretion rate and salivary outputs of sodium (Na), potassium (K), phosphorus (P), calcium (Ca), and magnesium (Mg) were measured in 4 sheep offered chaffed lucerne hay or ‘Grasslands Ruanui’ perennial ryegrass. Each sheep was fitted with a unilateral re-entrant cannulation of a parotid duct and a simple cannulation of a mandibular duct. During 2 periods of at least 24 h, the salivary outputs of each sheep on each diet were collected. Parotid salivary flow was continuous, with the output increasing markedly during feeding. The output of mandibular saliva was much less, and substantial secretion occurred only during feeding. In all animals, regardless of diet, the rate of secretion of Na, K, P, Ca, and Mg by the parotid gland was related to salivary output rate. Large amounts of Na, K, and P, and very small quantities of Ca and Mg were returned to the rumen. The 24-h outputs of Na, K, and P by the mandibular gland were much smaller, and the 24-h outputs of Ca and Mg were about half those of the parotid gland.