Genetics of the susceptibility to bloat in cattle

Abstract
A polyacrylamide gel electrophoresis procedure is described for quantitatively studying the lower molecular weight proteins found in bovine saliva.The protein bands were stained with Coomassie Brilliant Blue R250 and the gels were cleared using an electrolytic destainer.Using this technique,11 protein bands could be accurately quantified,whether expressed as percentages of the total protein entering the gel, or as pseudo concentrations. Band 4 protein showed the highest coefficient of variation and this appeared to result from problems of delineating this protein region.Data from a saliva-stimulation trial showed that oral administration of acetic acid (pH 2) increased saliva flow in the test animals two- and five-fold respectively, in cows of low and high susceptibility to bloat.Protein concentration was similar in both test and control animals,but more protein entered the rumen in the test animals as the result of higher saliva flows.Band 7 was the only low molecular weight protein shown to increase as a result of the acetic acid treatment.