Effect Of Early Weaning On Growth And Metabolism Of Three Sheep Breeds In Xinjiang

184 lambs of three sheep breeds in Xinjiang (China Merino(Xinjiang type), Kazak, Bayinbuluk sheep) were selected as samples, whose lambs weaned early at 40days and 60days respectively, fed with three milk replacers(protein level:20%,22%,24%). It is aimed at studying the effect of early weaning on growth and development, nutrition metaboilic level, physiological and biochemical indicator in serum of lambs, as well as physiological and biochemical indicators in serum and reproductive hormones of ewes. Control group was fed with milk from their ewes under natural grazing conditions. The results show:1. Growth performance of lambs:Body weight of three sheep breeds were higher than control group after weaning, ADG (average daily gain) of China merino(Xinjiang type) fed with milk replacer of 22% protein levels are significantly higher than control group(P<0.01). ADG of Kazak lambs fed with milk replacer of 20% protein levels are higher than control group(P<0.05). ADG of Bayinbulk lambs fed with milk replacer of 22% protein levels are higher than control group(P<0.05). China merino(Xinjiang type) and Bayinbulk lambs weaning at 40 days, fed with milk replacer of 22% protein levels, had the maximum economic returns. Kazak Lambs weaning at 40 days, fed with milk replacer of 20% protein levels, had the maximum economic returns. The conclusion was as following:It is feasible for lamb of three breeds to wean at 40day and 60 day, Moreover,40day weaning can get higher benefit rather-than that of 60day weaning.2. Nutrient utilization and digestion efficiency:Bayinbulk lambs weaning at 60 days, fed with milk replacer of 22% protein levels, were higher than the group of 20% protein levels milk replacer on the digestibility of DM, OM and N(P<0.05). Nutrient digestibility were not significant different among two weaning age when lambs fed with same level of crude protein milk replacer. There are not significant impact on nutrient utilization and digestion efficiency for lambs to wean at 40 and 60 days. Bayinbulk lams had the better nutrient utilization and digestion efficiency fed with milk replacer of 22% protein levels.3. The change of biochemical indicators in serum:(1)The change of TP, GLOB, ALB and SUN, as for SUN, China Merino (Xinjiang type) and Kazak lambs showed an increasing tendency, some experiment groups were higher than control group(P<0.05), Bayinbulk lambs were lower than control group(P<0.05). Early weaning did not cause changes in other indicators. (2)The change of TC, GLU, TG, HDL and LDL, as for TC, China Merino (Xinjiang type) and Kazak lambs showed a decreasing tendency, which the experiment groups of Kazak lambs was significantly lower than the control group (P<0.01). As for GLU, Kazak lambs showed an increasing tendency. Early weaning had not impact on TC, GLU and HDL of Bayinbuluk lamb in this experiment. (3) Some important enzymes in scrum, as for LDH, Bayinbulk lambs weaning at 60 days, fed with milk replacer of 22% protein levels were lower than control group(P<0.05). As for ALP, Bayinbulk lambs weaning at 60 days, fed with milk replacer of 22% protein levels were higher than control group(P<0.05).4. Immune indicators of lambs in serum(IgA, IgM, IgG and CP), as for IgG, China merino(Xinjiang type) lambs are higher than control group when fed with same level of crude protein milk replacer. As for CP, Bayinbuluk lambs weaning at 40 and 60 days, fed with milk replacer of 22% protein levels, are higher than control group(P<0.05), there are no significant difference on other indicators(P>0.05). There are no significant different between experiment and control group of Kazak lambs on immune indicators.5. The change of growth hormone in serum, China Merino (Xinjiang type) and Bayinbuluk lambs weaning at 40 days, fed with milk replacer of 22% protein levels, were higher than control group(P<0.05). As for INS, Bayinbuluk lambs weaning at 40 and 60 days, fed with milk replacer of 22% protein levels, were higher than control group(P<0.05). As for T3, Kazak lambs weaning at 60 days, fed with milk replacer of 20% protein levels, were higher than control group(P<0.05).6. Reproductive hormone, Physiological and Biochemical indicator of ewe in serum, the content of GLU was significantly increased in serum for three breeds. As for T4, China Merino (Xinjiang type) and Bayinbuluk ewes weaning at 60 days, were higher than control group (P<0.05). As for INS, Kazak ewes weaning at 60 days, were higher than control group (P<0.05). Early weaning increased the content of E2 in serum on Kazak and Bayinbuluk lambs. Meantime, Kazak ewes weaning at 40 days, were higher than Lactating ewes at LH (P<0.05).The experiment of growth and metabolism showed that Growth and development of three sheep lambs were good to wean at 40 and 60days. Lambs weaning at 40 days, had the maximum economic returns. indicators in serum showed:There were not significant impact on nutrient metaboilic level and humoral immunity from early weaning. As for ewes from early weaning, there was positive influence on physiological function and reproduction function recovering.