Study Of Feed Restriction Of Mongolian Ewes During Late Pregnancy On The Compensatory Growth Of Lambs And The Mechanism Involved

In this study, one hundred Mongolian ewes on their 90th day of pregnancy by oestrus at scheduled time and become pregnant in their second or third parity of average body weight 42.52±4.86kg , were randomly allocated to three dietary treatments during late pregnancy (90-150 days):restricted group1 (RG1, 0.175 MJME·kgw-0.75·d-1), restricted group2 (RG2, 0.33 MJME·kgw-0.75·d-1) and control group (CG, ad libitum), and with the aim of studying the effect of different restricted feeding energy levels during late pregnancy on the lamb compensatory growth of Mongolian ewes. The results were as follows:1 Feed restriction during late pregnancy did have effect on the lamb compensatory growth of Mongolian ewes.2 During the late pregnancy, Mongolian ewes had a good ability of adapt to lower nutrition and mobilize body reservation as well.3 On the condition of this experiment, lambs of RG1 were exhibited"portion compensatory growth", and lambs of RG2 were exhibited"full compensatory growth".4 There was a positive coefficient between the growth rate of restricted groups lamb during compensatory period and the severity of maternal restriction.5 The amount of hay intake of RG1 and RG2 were higher than CG by 4.83% and 17.53% during compensatory period respectively. The digestibility of DM, CP, Ca, P, NDF and ADF of the lambs in each group were not significant difference (P>0.05), the lambs of RG1 and RG2 were all exhibited positive nitrogen, calcium and phosphorus balance respectively.6 In the start of compensation, the contents of carcass meat water (P<0.01), dry matter (P<0.01), protein (P<0.01), fat (P<0.01) and ash (P<0.05) of RG1 significantly lower than CG, but only the carcass meat protein (P<0.05) of RG2 significantly lower than CG. In the end of compensation, except the carcass meat water content of RG1 significantly lower than CG, the other carcass meat contents had not significant different among the groups (P>0.05),however, the level of carcass meat fat and ash contents of RG1 and RG2 higher than that in CG.