Effect Of Different Energy And Regulating Agent On Growth Development And Conversion Efficiency Of Energy And Protein In Calves

27 healthy male China Holstein early weaning calves with the body weight of (107.96±14.48) kg and around 3.5 months ages were divided into three groups randomly. The effects of different energy sources (steam-flaked corn, corn+4% vegetable oil, corn) of calf starters and three regulating agent (probiotics, enzyme, mannan oligosaccharide) on the growth performance, conversion efficiency of energy and protein in calves were studied with a 3 X 3 Greco—Latin square design. Within the 150-day feeding trial, the amount of diets offered and refused was recorded daily and calves were weighted each period for investigation of growth performance. The digestion and metabolism tests were conducted by making use of full feces and urine collect approach to ascertain conversion efficiency of energy and protein in calves.The results showed:steam-flaked corn, corn+4% vegetable oil, corn as main energy sources of calf starters had no significant effects on dry matter intake of 3-8 months Chinese Holstein bull calf (P>0.05). But corn+4% vegetable oil significantly (P<0.05) increased the daily gain, remarkably (P<0.05) decreased the feed to gain ratio compared with calves fed starters with steam-flaked corn or corn. And calves fed starters with corn+4% vegetable oil showed higher net protein utilization, biological value, the deposition of crude protein, the deposition of energy and the rate of NEp/ME than other treatments, but not significant (P>0.05). The items were (1404.26±197.99) g, (3.51±0.36) kg, (30.59±1.13)%, (46.86±2.38)%, (234.73±26.76) g, (22.55±5.40) MJ, (41.27±2.58)%. Probiotics, enzyme, mannan oligosaccharide as three regulating agent had no significant effects on average daily gain, dry matter intake, the feed to gain ratio, digestibility of crude protein, net protein utilization, biological value, the deposition of crude protein, the deposition of energy and the rate of DE/GE, ME/DE, NEp/ME. The items were (1298.48±3.50) g, (3.81±0.13) kg, (65.35±1.00)%, (29.94±0.18)%, (45.83±0.44)%, (228.21±4.90) g, (21.79±0.73) MJ, (67.75±0.79)%, (87.84±0.06)%, (40.62±0.68)%.In summary, with the same protein level, corn+4% vegetable oil as main energy sources of calf starters showed better effect on the growth performance, conversion efficiency of energy and protein compared with calves fed starters with steam-flaked corn or corn.0.2% probiotics,0.1% enzyme,0.16% mannan oligosaccharide as three regulating agent had similar effects on the growth performance, conversion efficiency of energy and protein in 3-8 months Chinese Holstein calf.