能量水平对早期断奶犊牛消化代谢及血清指标的影响

 【目的】研究代乳品中能量水平对早期断奶犊牛不同生理阶段日粮营养物质消化代谢规律及血清学的影响。【方法】试验选取12头新生荷斯坦公犊牛，分为低、中、高3个能量组，每组4头，分别饲喂蛋白水平相近、能量水平为18.51、19.66和 20.80 MJ?kg-1的3种代乳品。于犊牛12～20 d、22～30 d、32～40 d、42～50 d和52～60 d期间进行5期消化代谢试验;同时在犊牛21、31、41、51、61日龄清晨空腹采集血液样品进行分析。【结果】随日龄的增加，犊牛DM、OM、GE表观消化率及N、P沉积率均呈上升趋势;高能组犊牛全期DM、OM表观消化率及Ca的沉积率均显著低于中、低能组（P＜0.05）;血清尿素氮、血糖及甘油三酯的水平不受代乳品能量水平的影响，但日龄显著影响哺乳期犊牛血清甘油三酯含量（P＜0.05）。【结论】中等能量代乳品有利于GE表观消化率及N消化代谢率的提高，低能量代乳品则有利于犊牛对钙、磷等矿物质的消化利用。

Effects of Different Energy Levels on Nutrient Utilization and Serum Biochemical Parameters of Early-Weaned Calves

【Objective】 The current study was performed to investigate the effects of different energy levels on nutrition’s digestion metabolism and serum biochemical parameters of early weaned calves. 【Method】 Twelve neonatal Holstein calves were selected and assigned randomly to receive 1 of 3 treatments that contained 18.51, 19.66 and 20.80 MJ?kg-1 gross energy, respectively (n=4 per treatment). Digestion and metabolism trials were carried out at 5 phases (12-20, 22-30, 32-40, 42-50, 52-60 d). At the same time, blood metabolites were determined at 21, 31, 41, 51 and 61 days of age prior to morning feeding. 【Result】The results indicated that either DM, OM, and GE apparent digestibility or N and P retention tended to increase as age advanced. The average value of DM、OM apparent digestibility and Ca retention in high-energy treatment were significantly lower than that of other groups (P＜0.05). There were no significant differences in the concentration of serum glucose, triglyceride and urea N among treatments, whereas a significant effect of age was found on the level of triglyceride (P＜0.05). 【Conclusion】 To sum up, the medium-energy milk replacer seems to be more benefical for GE digestibility and N utilization, whereas low-energy milk replacer appears to be more rewarding for Ca and P utilization.