Study on Energy Metabolism Rule and Requirement of 40 to 90 kg Yak Calve
The purpose of this experiment was to explore the energy metabolism rule and requirement of 40 to 90 kg yak calve.Thirty-five healthy(60±3)-day old yak calves(male)with similar body weight were divided into 3 groups,namely the initiation slaughter group(IS group,7 calves),middle slaughter group(MS group,7 calves)and final slaughter group(FS group,21 calves),while the FS group was subdivided into the ad li-bitum feeding group(AL group,7 calves),70％feeding group(IR70 group,7 calves)and 40％feeding group(IR40 group,7 calves).The pre-experimental period lasted for 30 days,and the experimental period lasted for 90 days.The yak calves in AL group,IR70 group and IR40 group were fed the basal diets in a gradi-ent manner.When the body weight of yak calves in IS group,MS group and AL group reached 48,64 and 88 kg,5 yak calves in each of the 5 groups were selected for slaughter.The digestive metabolism experiment and gas metabolism were conducted before two weeks of the experiment end.The results showed as follows:1)the final body weight,average daily weight gain and average daily feed intake of AL group were significantly high-er than those of IR70 group and IR40 group(P＜0.05).2)The apparent digestibility of crude protein,crude fat,neutral detergent fiber and acidic detergent fiber of AL group were significantly higher than those of IR70 group and IR40 group(P＜0.05),the gross energy,fecal energy,metabolic energy and digestive energy of AL group were significantly higher than those of IR70 group and IR40 group(P＜0.05),and the gross energy digestibility and gross energy metabolic rate of AL group and IR40 group were significantly higher than those of those of IR70 group(P＜0.05).3)The oxygen consumption and carbon dioxide production of AL group and IR70 group were significantly higher than those of those of IR40 group(P＜0.05).There were no significant differences in methane production and respiratory entropy among the three groups(P＞0.05),and the respira-tory entropy ranged from 0.65 to 0.80.4)The energy contents in tissues from high to low was:fat＞muscle＞blood+viscera＞skin＞bone＞hair.5)For 40 to 90 kg yak calves,the net growth energy requirement with av-erage daily gain of 100 to 500 g/d was 1.37 to 8.10 MJ/d,and the model of growth net energy requirement was:log10 energy=0.830 9+1.232xlog10 empty body weight.The regression equation for maintaining net ener-gy requirement was:log10 heat production=0.000 138×metabolic energy intake+2.573,and the maintaining net energy requirement was 374.1 kJ/kg SBW0.75.In summary,it was concluded that the respiratory entropy of gas metabolism of 40 to 90 kg yak calves range from 0.65 to 0.80.the maintaining net energy requirement is 374.1 kJ/kg SBW0 75,the growth net energy requirement with average daily gain of 100.00 to 500.00 g/d is 1.37 to 8.10 MJ/d,which filled in the basic parameters for nutritional needs in feeding standards of yak calves.[Chinese Journal of Animal Nutrition,2024,36(4):2512-2523]
yak calvesenergy requirementfeeding levelsdigestion and metabolismgas metabolism
万方数据
维普
