Ruminal pH in cattle (Bos primigenius f. taurus) and moose (Alces alces) under different feeding conditions: a pilot investigation

Abstract

Feeding recommendations for captive wild ruminants strictly restrict the use of high-starch/low fibre concentrates and fruits and vegetables, because of their potential to induce acidotic conditions in the forestomach. Nevertheless, such items are still used, and actual measurements documenting the consequences are rare. We used a captive moose (Alces alces) and two domestic cows (Bos primigenius f. taurus), equipped with intraruminal pH sensors, to monitor the short-term effects of five diets (a ‘natural diet’ of browse for moose and grass hay for the cows; a grass diet; an alfalfa hay diet; and a diet where concentrates, apples and carrots were offered, along with an ad libitum roughage source, at two increasing levels – ration 1 and 2, respectively). Lowest mean pH and highest pH variability were measured on ration 2. The provision of concentrates/produce in two meals per day (0800 and 1600) resulted in distinct pH differences between day and night periods. Differences in the amount of roughages accepted (for example, the moose refused the freshly cut grass, and the cows had low intakes on the alfalfa hay offered) could explain differences in the level and course of pH observed between diets. No particular species differences were noted that did not relate to roughage acceptance. These results underline that using roughages, and restricting/avoiding the use of concentrates and produce, will result in more stable forestomach conditions that are possibly favourable for ruminant health.