Some Physical and Chemical Properties of Bovine Saliva which May Affect Rumen Digestion and Synthesis

Abstract

An investigation was conducted on 77 samples of saliva from dairy cattle to ascertain some of this secretion's chemical and physico-chemical properties. The average water content of 36 specimens was 99.12 per cent. The average pH of 54 samples protected by neutral paraffin oil from carbon dioxide loss was 8.53, whereas the average pH for the unprotected samples was 8.71. No appreciable variation was noted in the pH of saliva collected at 6-hour intervals over a 24-hour period, and the time of collection relative to the feeding time had no apparent effect on the reaction of the saliva. An analysis of 75 saliva samples showed an average ascorbic acid concentration of 0.15 mg. per cent, while the average plasma ascorbic acid level of the same animals was 0.47 mg. per cent. The deodorizing and surface active properties of cow's saliva were demonstrated. The surface tention of 55 samples was 47.10 dynes per cm. at 29° C., while typical adsorption curves were derived from the uptake of benzene by saliva. since dried cow's saliva took up benzene in a manner characteristic of adsorption, it was believed that the absorbent materials of saliva were altered in some way by drying, resulting in the loss of the adsorbing property. © 1949, American Dairy Science Association. All rights reserved.