Physical and Chemical Changes in Bovine Saliva and Rumen Liquid with Different Hay-grain Rations

Saliva and rumen liquid samples were collected from two cows that were fed 20, 40, 60, 80, and 100% hay rations.The viscosity of saliva (mean 99 c.p.) was greater 3 hr.after feeding than before feeding and the pH (mean 8.2) increased as the proportion of hay increased.The ash of saliva (mean 0.73%) was greater with the high-grain rations.TotM salivary nitrogen was 20.1 mg.% for the 20% hay ration and averaged 14.9 rag.% for the 40 to 100% hay rations, ttexosamines (mean 4.3 rag.%) were higher on the high-grain rations.The rumen liquid samples were centrifuged at 25,000 × G. and the supernatant analyzed.The mean dry matter content was 1.71% and the ash content was 0.79%.Sodium (mean 234 rag.%) increased as the hay content increased and was higher for the cow which tended to bloat than for the one which did not.ttexosamines (mean 3.7 mg.%) were also greater for the bloaty cow, but tended to increase in both cows with increasing proportions of grain.The total nitrogen of rumen liquid (mean 37.1 mg %) was highest on the 20% hay rations, was higher after feeding than before, and was higher for the bloaty cow than for the one which did not bloat.