Dry matter intake, nutrient digestibility, chewing activity, and ruminal fermentation of raising Japanese Black steers fed diets containing whole crop corn silage at three levels

Abstract

AbstractThe effects of the inclusion level of corn silage (CS) in an ensiled total mixed ration (TMR) on feed intake, nutrient digestibility, chewing activity, and ruminal fermentation were investigated. Six Japanese Black steers during the raising period were used in a replicated 3 × 3 Latin square design with three dietary treatments: a diet containing 40.0%, 52.5%, or 65.0% CS on a dry matter (DM) basis. The three TMRs, in which the crude protein (CP) and DM levels were adjusted, were vacuum‐sealed and then stored for >30 days. Increasing the inclusion level of CS caused lower pH values and higher lactate production in the ensiled TMR. The DM intakes by the animals that received three dietary treatments were identical. The feeding of the TMR with the highest CS inclusion level resulted in slight decreases in total DM digestibility, and content and intake of total digestible nutrients, whereas the nutrient digestibilities (CP, non‐fibrous carbohydrate, acid detergent fiber, and neutral detergent fiber) were not significantly different among the dietary treatments. The eating and ruminating times by the steers fed the TMRs were elongated concomitantly with the increase in the CS inclusion level. The feeding of TMRs with higher CS inclusion led to slower fermentation in the rumen. These findings suggest that a CS inclusion level up to approx. 50% in a TMR should be considered a reasonable level for Japanese Black steers during the raising period.