The use of lipid - calcium complex for lactating cows. 2. Ruminal pH and ammonia levels and rate of digesta passage

Abstract

The effect of a lipid-calcium complex fed to lactating cows, on the ruminal pH and ammonia levels and the rate of digesta passage based on one - and two - compartmental models, was studied in two trials utilizing maize silage or sugarcane. Ruminal pH showed a quadratic behavior in both experiments and the mean value for all diets was 6.0. The ruminal ammonia concentration in Experiment 1 decreased linearly at the rate of 1.84 mg/100 ml/hour when the calcium complex was present and showed a quadratic behavior when it was absent, with the maximum value of 22.03 mg N-NH₃/100 Mg. In Experiment 2 the ruminal ammonia concentration showed a quadratic behavior; the respective values for diets with and without the complex were 15.71 and 18.76 mg/100 ml. The rate of rumen digesta passage (one compartment model) was higher (P < 0.05) for corn silage diet (6.44%/h) than for sugarcane diet (4.11%/h). The rates of passage determined by the one or two compartment models in Experiment 1 were similar (P > 0.05).