Study On Plant Protein In Place Of Milk Protein In Calf Milk Replacers

The experiment was conducted to study the effects of different plant proteins as proteinsource of milk replacers on performance, nutrient apparent digestibility, N balance, serumindexes , health condition and economy benefit in calves. Sixteen Holstein male calves with 8~12-day-old were allocated to four dietary treatmentsaccording to the principle of body weight and birth similarity. Each group was four calves.Protein of milk replacers(MR)in A, B and C groups respectively came from isolated soyprotein(ISP), soy protein concentrate(SPC)and SPC+corn gluten meal(CGM). The calvesfed milk in D group were taken for the control. The trial results showed that body weights, average daily gain(ADG)and bodymeasurement of calves between three milk replacers and milk were not significantly different(P>0.05)during whole trial period. During whole trial period, calf performance inSPC+CGM group was higher than that in milk group. Before weaning, calves performance inISP and SPC groups were poorer than that in milk group, but after weaning, growth rate ofcalves in ISP and SPC groups were faster than that in milk group, which showed calves fedMR got compensatory growth in late rearing. The results showed that nutrients apparent digestibilities of calves fed MR were lowerthan those of calves fed milk, but difference were not identical. DM, CP, OM and EE apparentdigestibilities between SPC group and milk group had significantly different(P<0.05). ForDM and OM apparent digestibilities, difference were not significant between ISP, SPC+CGMand milk groups, but CP and EE apparent digestibilities between these two MR and milk hadsignificant difference(P<0.05). N retention and N retention rate of calves fed MR were lowerthan those of calves fed milk(P<0.05). N retention and N retention rate of calves fedSPC+CPF milk replacer were higher than those of calves fed ISP and SPC milk replacers(P<0.05). In this study, correlation of measuring nutrients apparent digestibilities with totalfeces collection method and indicator method was higher, and difference was significant(P<0.05),which indicated that measuring apparent digestibilities of liquid feed with II摘　 要indicator method was advisable. The trial results indicated that serum biochemistry indexes and serum IgG of calves fedMR and milk were no difference (P>0.05),but those of calves fed milk were higher thanthose of calves fed three MR. At the beginning of trial, calves fed MR excreted sofer feces,which indicated calves required some times to accept MR. Calves had a shorter adaptive phaseon ISP and SPC+CGM milk replacers, while calves required a longer adaptive phase on SPCmilk replacer. In this experiment, costs of rearing a calf with MR were lower than that with milk.During experiment period, costs of rearing a calf with ISP, SPC and SPC+CPF MR wererespectively lower 17.05%, 19.57% and 25.67% than consuming cost with milk. Master Candidate: Ren Huibo Supervisor: Prof .Zhang Yonggen Major: Animal Nutrition and Feed Science...