Dietary Buffers and Ruminal and Blood Parameters of Subclinical Lactic Acidosis in Steers

Publisher Website
Google Scholar
Abstract
Four ruminally cannulated Holstein steers were fed an 85% ground, ensiled high-moisture corn diet at a level of 90 g of dry matter per kilogram of metabolic body size daily in two equal feedings. The evening prior to sampling days, feed was reduced by half and subclinical acidosis was produced the following morning by feeding the entire daily allotment of feed in one meal. Feed not consumed within 30 min was placed in the rumen through the ruminal cannulae. Effects of feed additions of 2% sodium bentonite, 1% sodium bentonite plus 1% dolomitic limestone (dolomite), or 1% sodium bentonite plus 1% potassium bicarbonate (KHCO3) on ruminal and blood parameters of acidosis were measured. Ruminal pH was lowest 4 to 8 hr post-feeding. Steers fed the diet containing bentonite and KHCO3 had higher ruminal pH at 4 and 8 hr post-feeding. Lactate concentrations of steers fed the control, bentonite, bentonite plus dolomite, and bentonite plus KHCO3 diets increased by 58.7, 50.1, 28.7 and 43.6 mmoles/liter, respectively, by 2 hr post-feeding. Ruminal glucose and total VFA concentrations, molar percentages of individual VFA's, and ruminal fluid osmolalities were not affected (P>.05) by treatments. By 4 hr post-feeding, blood bicarbonate concentrations of steers fed the control, bentonite, bentonite plus dolomite and bentonite plus KHCO3 diets were decreased by .2, 2.6, 3.4 and 1.5 mEq/liter. During 12- to 24-hr post-feeding, blood bicarbonate concentrations of steers fed diets containing bentonite plus either dolomite or KHCO3 increased, whereas blood bicarbonate concentrations of steers fed the control and bentonite diets remained low. The results indicate that blood parameters of acid-base status in addition to ruminal parameters should be measured in evaluating acidosis. Copyright © 1979. American Society of Animal Science . Copyright 1979 by American Society of Animal Science.