4および6カ月齢の子牛の絶食時熱産生量

概要

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Fasting heat production of calves fasted for 4 days was measured using 10 Holstein castrated male calves at 4 and 6 months of age after 3-week-feeding at maintenance level. Compositions of ruminal gas phase were also determined at 24, 44, 48, 68 and 92 hours after last meal. Results were obtained as follows: 1) Compositions of ruminal gas phase drastically changed within 48 hours, but reached a plateau after 68 hours of fasting. Changes of compositions of ruminal gas phase indicated that 4-day-fasting satisfied to reach the quasi-postabsorptive state of calves. 2) Calves lost weight at an average of 1.6kg per day by the fasting. After 4 days of fasting the weight of calves decreased to 0.928 of live weight at maintenance feeding level. 3) No difference was observed in fasting heat production between 4- and 6-month-old calves. Fasting heat production of calves at 4 to 6 months of age averaged 385 kJ/kg0.75•day and well agreed with that calculated by applying mean fasting weight of the present study to the equation shwon by ARC (1980). Fasting heat productions reported by several workers were too high to apply to young calves at the age of 4 to 6 months.
社団法人日本畜産学会の論文