Effect Of Energy Levels On Growth Performance&Digestibility Of The Nutrients And Methane Production Of Shaanbei White Cashmere Goats

The feeding trials, digestive metabolism test and measure of methane emission werecarried out for the studies of energy levels on growth performance, digestibility of thenutrients and methane emission of Shaanbei white cashmere goats during growing period, anddetermine the energy requirements of this period.Seventy-two4-month-old Shaanbei White Cashmere Goats were divided randomly intoequal3groups,six repeats for per group and four goats per repeat, which were fed digestibleenergy (DE)3levels of experimental diets,the digest energy and were set by NRC (1981)goat feeding standard recommendation,that was separately80%（8.37MJ/kg）,90%（9.41MJ/kg）and100%（10.46MJ/kg）of the nutrition need standard which expecting to gain150g/d average and weight30kg. The trial period lasted for50days, including preliminarytrial period of10d. All the feces and urine were collected for a ten-days digestive metabolismtest(including preliminary trial period of7days).The methane were collected at the sametime.The results showed as follows:(1)Energy levels of the dietary had no significantly influence on DMI (P>0.05);Theaverage daily gain of Shanbei White Cashmere Goats increased with the increasing digestibleenergy levels (P<0.05);the ratio of feed and meat decreased along with the increasingdigestible energy in a linear curve (P<0.05).(2)With the energy levels of dietary increasing, the apparent digestibility of DM、CP、GE、EE、NDF increased significantly (P<0.05).；the apparent digestibility of ADF slightlydecreased but there were no significant difference(P>0.05).The GE metabolic rate and DEmetabolic rate of Shanbei White Cashmere Goats increased significantly with the increasingdigestible energy levels (P<0.05)..The GE metabolic rate of high-energy group was30.72%and19.05%higher than the low group and medium group respectively, digestive energymetabolic rate was5.12%and15.12%higher respectively.(3)The dietary with higher energy levels has increased the gross yield;the gross yield hasdecreased by0.52yuan every day when the goats taking low-E dietary. it decreased by0.37yuan every day when the goats taking Mid-E dietary;Under the condition of this experiment, the dietary with DE of10.65MJ/kg can provide the best economic benefits.(4) The emissions of feces、urine and methane significant reduced with the increasingdigestible energy levels (P<0.05).(5) Under the condition of this experiment，the best nutrition level the digestible energywas10.46MJ/kg.