Bloat In cattle 44. Comparison of mixed bovine saliva collected by three different methods

Abstract

Flow rates and protein composition of mixed bovine saliva collected by the 'bit' (aspiration from the mouth) and cardial methods were compared to saliva secreted with the food bolus, using 4 cows of known bloat susceptibility. Average flow rates for saliva collected by the cardial, bolus, and 'bit' methods were 900,310, and 25 g for 10 min, respectively. Protein nitrogen concentration was significantly lower in cardial than in 'bit' saliva (P<0.001) but not significantly different from bolus saliva. Sialic acid concentrations were similar for all collection methods. Two high molecular weight proteins were present in saliva. Mucin was a major component of cardial and bolus saliva, whereas bovine salivary mucoprotein was a major component in 'bit' saliva. Low molecular weight salivary proteins were identified by polyacrylamide gel electrophoresis and by crossed immunoelectrophoretic techniques. All of the proteins detected in cardial saliva were identified in bolus saliva. Band 4 protein was not detected ( < 0.04 JLg/ml) in ‘bit’ saliva from any of the 4 cows. ‘Bit’ saliva contained mainly Bands 1, 3,8, and 9. There was significantly (P<0.00l) more Band 8 and significantly (P<0.00l) less Band 10 in 'bit' saliva than either bolus or cardial saliva. No significant differences in concentration of Band 9 protein were found between methods. With the exception of sialic acid, the cardial collection method showed highly significant (P<0.00l) differences between cows for all parameters measured. 'Bit' collections did not reveal betweencow differences for Band 4, 9, or 10 proteins, but differences for Band 4, 9, or 10 proteins, but differences for Band 4, 9, or 10 proteins, but cows differed in Band 8 (P<0.01) and sialic acid (P<0.05) concentrations. Bolus saliva only showed Band 4 concentrations to differ significantly (P<0.001) between animals.

Keywords:

• saliva
• proteins
• mucoprotein
• mucin
• electrophoresis
• collection methods
• bloat
• bovine
• cattle