关键词: 犊牛; 代乳品; 脂肪; 生长性能; 血液生化指标

Abstract: Feeding trials have been performed to investigate the effects of increasing fat levels of milk replacer on growth performance，changes in selected blood metabolites and starter consumption，which provides scientific basis to research on the development of calf growth and fat requirement. It is also instructive for the practical operation of calf early-weaning and breeding. Twelve newborn Holstein calves were used and assigned randomly to receive 1 of 3 experimental treatments consisted of 8%， 13% and 17% fat， respectively (n=4 per treatment). A pellet starter was offered ad libitum and refusal were weighed daily. Changes in body weight、growth parameters and concentration of blood metabolites were determined at 10， 20， 30， 40， 50 and 60 days of age prior to morning feeding. The starter consumption of calves fed with EE8， EE13 and EE17 was 706.9,666.9,569.3 g，respectively. And the average daily gain (from day10~60) was498，544g and 488 g/day， respectively.Body weight gains of EE13 treated group was greater than the other groups. On the 60 days of age， wither height、body length and cannon bone circumference were significantly higher with EE13 treatment(P<0.05).There were no significant differences in the concentration of serum glucose、triglyceride and urea N among treatments， whereas a significant age effect was found on the level of triglyceride(P<0.05). The growth rate and starter consumption improved as age increased. Low-fat content (EE9) milk replacer could not satify the energy requirement of calves，on the other hand，high level of fat content (EE17) impressed starter consumption that would delay the development of rumen in the animal. Thus， medium-fat milk replacer (EE13) seemed to be the most optimal level for the calves.In addition，no significant differences in the concentration of blood metabolites was observed among groups.

Key words: calf; milk replacer; fat content; growth performance; blood metabolites