| Effects of Dietary Protein Levels on Nutrient Digestionmetabolism and Production performance in Adult Female WapitiBalance trials (n=4) and feeding trials (n48) and regression analysis were used to estimate the optimum dietary protein requirements and nutrient digestion-metabolic laws in adult female wapiti. In fallow period (from Aug. 20 to Sept. 20 in 1998), the balance trials were conducted in order to value the metabolic laws of different protein diets. In the front, middle and late pregnancy periods, the wapiti were fed with the same diets of 12% crude protein(CP), and the balance trials (n=4) were conducted for valuing the digestionmetabolic laws respectively. In the annual period (from 20 August 1998 to 20 August 1999), 48 adult female wapiti were randomly allocated to 4 groups which were housed inside and fed 4 different protein diets treatments (mean CP: 8.54, 9.82, 11.28 and 12.68 during pregnancy; 10.94, 12.85, 14.61 and 16.22 during lactation ) respectively, and the digestive and feeding trials were conducted. Using the effects of different protein diets on birth date, calving rate, calves daily live-weight gains and weaning live-weight to evaluate the optimum dietary CP requirements, the results were obtained as fellows:1 In the feeding trails, the weak calves mortality rate was 27.27% when the adult female wapiti were feed with mean CP 8.54% diets in the pregnancy. There were no weak calves when the adult female wapiti were feed with mean CP 9.82%, 11.28% and 12.28% diets in the pregnancy. The birth live-weight, mean birth date and the wearing live-weight had no significant difference (P>0.05) in the 4 groups.2 In the lactation, the daily live-weight gains of their calves fed with mean CP 10.94% and 12.85% diets were lower than those of mean CP 14.0 1% and 16.22% diets(P<0.05), and the mean daily live-weight gains of 4 groups were 490.38g1d, 492.62g1d, 609.SgId and 591 .83g1d, respectively.3 The linear relationship between dietary crude protein and apparent digestibility was significant: N digestibility(%) 45.465Ln(x)-46.332, (R2 = 0.9035, n=12, P<0.0 1).404 In the digestive tr8i1s, the aPparent digestibility were higher in the grouPs fed withhigh CP diets (ll.28% and l2.68%) than Iow CP diets (CP 8.54% and 9.82%) duringpregnancy(P>0.05). The aPparent digestibility of protein, dry matter(DM) and organicmatter(OM) had no significant difference in 4 grouPs. During the front, late pregnancy andIactation, the aPparent digestibiIity of protein, DM and OM increased gradually5 In conclusion, the proper dietary CP levels was 9.82% in pregnancy and l4.6l% inlactation. The DMI was more in the low protein groups compared with high protein grouPsIn the feeding trails.6 In fallow period, the effect of differellt protein Ievel diets on the waPiti dry matterintake (DMI), oraanic matter intake (OMI) and nitrogen intake(NI) were significan(P<0.05), and the diet intake of those which were fed on the high protein diets was more.The effect of different prOtein level diets on the aPparent digestibility of DM, OM and Nwere no significat difference W>0.05). The N deposition were not affected by two proteinlevel diets in the trials (P>0.05), but the N metabolic rates were affected significantly(P<0.05), and the N metabolic rae of waPiti fed the higher protein level diet was loweL7 DMI, OMI, DM and OM excretion were higher in the lat6 pregnancy than front andmiddIe pregnancy (P<0.05), but the aPparent digestibility of DM and OM were nosignificant difference (P>0.05).8 NI was higher in the front and late pregnancy than middle pregnancy (P<0.05), but theN excretion and N apparent digestibiIity of all period had no significant difference(P>0.05). The mean N apparent digestibility was 67.53%.9 The N depositions and biological value (BV) were higher in the front and latepregnancy than middle pregnancy (P<0.05), and the N depositions and BV had nosignificant difference betWeen front and late pregnancy (P>0.05).l0 The serum urea...
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