Saliva collection and relationship between lactate concentration in blood and saliva of exercising horses

The aims of this study were to examine whether sufficient volumes of saliva can be collected for lactate analysis in exercising horses and to establish the relationship between blood and saliva lactate concentration. Saliva was collected for 30 seconds after exercise with a commercially available cotton swab Salivette® from two sites: At the height of the 3rd premolar in the maxilla (upper site) and under the tongue at the level of the frenulum linguae (lower site). Blood was taken from the jugular vein. Horses were submitted to two types of standardized exercise on a treadmill: Continuous exercise and an incremental exercise step test. The average (± standard deviation) volume of saliva sampled at the upper site was 390±280 μl, and at the lower site 450±310 μl. The lactate concentration in saliva after continuous exercise sampled at the upper site was 2.21±1.97 mmol/l, and at the lower site it was 3.76±2.31 mmol/l. There was no significant correlation between lactate concentration in blood and upper site saliva, and blood and lower site saliva after continuous exercise and during incremental exercise step test.