Concentrate feeding and ruminal fermentation. 3. Influence of concentrate ingredients on pH, on DL-lactic acid concentration in rumen fluid of dairy cows and on dry matter intake.

Abstract

Concentrate ingredients (maize meal, coconut oilmeal, maize gluten feed, citrus pulp, tapioca and soya bean oilmeal) were given daily at 0900 h into the rumen of 4 cows for 5 successive days. Hay was given freely at 1300 h. Between experimental periods there were intervals of at least 17 days when hay was given at 0800 and 1700 h. In a second experiment 6-kg amounts of 1:1 mixtures of 2 ingredients were given. Lowest pH and highest concentrations of D- and L-lactate in rumen fluid were reached 2 to 3 h after ingredients were given. Lowest pH and highest D- and L-lactate concentration in rumen fluid relative to the situation after citrus pulp was given, taken together as the potential risk of lactic acid acidosis (RLA), was best correlated with the content of glucose plus fructose (GF) and soluble protein (SPROT); RLA = 1.47GF + 0.49SPROT + 22.50 (r = 0.89). When combined ingredients were given, pH and D- plus L-lactate concentrations differed from values calculated from results after the same ingredients had been given separately. (Abstract retrieved from CAB Abstracts by CABI’s permission)