Influence of the composition of the ration and the feeding frequency on ph-regulation in the rumen and on feed in-take in ruminants

The author illustrates that a certain ratio between roughage and concentrates in the rations of dairy cows is necessary rather than depending exclusively on an increase of the amounts of concentrates for meeting the energy requirements at higher levels of production. In general, when lactation performance is high, merely the essential supply of concentrates entails a decrease of milk fat content, or, with an insufficient energy supply, the milk protein content drops. These relations are explained by a diagram on protein fermentation and bacterial protein synthesis.Higher feeding frequency allows higher intake of concentrates without a decrease of pH in the rumen. Hence the ratio of C₂:C₃ (acetic: propionic acid) in the rumen tends towards 3:1 instead of lower ratios, which prevents a decrease of milk fat content. The higher cellulolytic activity at the higher pH leads to higher intake of roughage. With automated systems for higher feeding frequencies it will be possible to increase milk production without decrease of milk fat content and other metabolic disorders. The better energy supply will lead to a better supply of microbial protein as well and therefore prevent a decrease in milk protein content.