Abstract
To estimate the metabolizable energy requirement for maintenance (MEm) of dry cows given diets mainly containing whole crop rice silage, regression analysis were carried out by two methods. The first analysis was carried out using data from a series of 37 complete energy balance trials with indirect calorimetry. The MEm was calculated as metabolizable energy intake at zero energy retention according to regression equation. The other method was based on the integration of heat production (HP) associated with animals’ activities during indirect calorimetry. Eating, ruminating and standing activities of animals were monitored, and then energy expenditures for resting, eating, ruminating and standing were calculated by multiple regression analysis. The MEm value was calculated as heat production for animals’ activities consuming a zero balanced-energy. The MEm calculated from data of the balance trial was 121.6kcal・kgBW−0.75/day, whereas MEm predicted from estimates of HP measurements was also 121.6kcal・kgBW−0.75/day. Considering both the chewing time and the standing time, the MEm ranged from 118.6−125.8kcal・kgBW−0.75/day. It is concluded that the MEm of cows given a whole crop rice silage is 121.6kcal・kgBW−0.75/day, and this value is well approximated with MEm value (116.2kcal・kgBW−0.75/day) shown by Japan Feeding Standard for Dairy Cattle.
