Influence Of Lactulose Of Immunity & Fecal Bacterial Flora On Calves In Perinatal Period

This thesis selected lactulose as substitute for antibiotic, influence of immunity&fecal bacterial flora of lactulose on calves in perinatal period has been researched, the effect of lactulose in milk for calves' health and growth function has been appraised.The experiment has been carried on 25 newborn Holstein male calves which were born by same passel youth cows from Australia in the same dairy farm.Calves had been divided into 5 groups (5 calves each group)conform to the bom time. Unit group design had been used to make the certain additive of each calf from firstborn to 15th day. Feed additives were: A: control group, with no lactulose or antibiotics; B: aureomycin group, according to practical calves' breeding in China, each calf were given 10000 IU/d from 3^rd day to 15^th day; C: admixture group, lactulose & aureomycin; D: lactulose group, 10g/d one calf; E: lactulose group, 15g/d one claf. Such items had been tested: Body weight&body size;Diarrhea index; Amount of coli&bifidobacteria which were cultured from calves' excrement; Analysis of calves' excrement with Denaturing Gradient Get Electrophoresis(DGGE);Immunity organ index; Some items in blood: T, B lymphocyte, lymphocyte conversion rate, C reactive protein (CRP), IgG; Wall thickness of Small intestine.The results were as follows:(1)Lactulose had no significantly effect to growth performance of calves in perinatal period. Average body weight of firstborn calves, 8^th day calves, 16^th day calves were: 37.84±3.66kg , 42.22±4.34kg. 45.66±4.26kg, there were no significant among groups(p>0.05). Differences of average daily gain were not significant among groups(p>0.05), the majority of body size were the same(p>0.05). Average daily gain(ADG) from newborn^8th d(0.63kg/D) was higher than the ADG from 8^th d to 16^th d(0.43kg/D). The changes of body size was same as body weight, there were no significant among groups.(2)Lactulose reduced the diarrhea rate, but the effect was inferior to the aureomycin or the two were associated use. The diarrhea index of group A is highest(17.33%), next is group D (10.67%),afterwards is groupE(8.00%), group B(5.33%),group C(2.67%). Group C was significantly less than group A.Lactulose and aureomycin had reduced the calves' diarrhea rate, they showed coordination effect(3)Lactulose suppressed the multiplication of harmful bacterium such as coliform, it promoted the multiplication of specificity bacterium such as bifidobacteria, and the effect boosted up when lactulose and aureomycin had been used together. The amount of coliform and bifidobacteria from excrement of newborn calves were small, respectively is 0.41+0.09 ten thousand/g, 0.03±0.02 ten thousand/g.