Effects Of Dairy Cattle Rumen Material Fermentation And Mineral Substance Metabolism In Vivo Added Different Zinc Sources And Levels Diets

Three rumen fistulated Holstein dairy cattle were used to study the effects of three levels of inorganic zinc,three levels of organic zinc and three levels of mixture(composed by proportional inorganic zinc organic zinc) in a replicated 3*3 Latin Square design , by measuring the digestibility of the major nutrition ingredient of the diet,rumen inner enviroment,rumen efective degradation and mineral substance metabolism, optimal zinc doses was determined. Aimed to provide scientific basis for better exploitating and utilizing zinc under the condition of dairy cattle healthy and security.1. Diet composing ,different zinc source and levels of zinc.1.1 Diet composing.Foundation diet were composed by mix concentration,corn silage and Chinese wildrye.The proportion of concentration and coarse feeding was 30:70.In coarse feeding,the proportion of the corn silage and Chinese wildrye is 50%.Concentration were composed by corn50%,soyben meal 30%,wheat bran 17%,salt 1%,calcium phosphate 0.3%,stone power 0.7%, vitamin premix 1%.1.2 Different zinc source and levels of zinc.Control group:only fed foundation die(tL1),it was not supplement zinc sulphate(ZnSO₄) and methionine zinc(Met-Zn).Experiment one, ZnSO₄ was supplemented to foundation diet,the levels of zinc respectively were 40mg/kgDM(L2),100mg/kgDM(L3),300mg/kgDM(L4) ; Experiment two, Met-Zn was supplemented to foundation diet,the levels of zinc respectively were 40mg/kgDM(L5),100mg/kgDM(L6),300mg/kgDM(L7);Experimentthree,ZnSO₄ and Met-Zn mixure was supplemented to foundation diet,total zinc quality is 100mg/kgDM,the proportion of ZnSO₄ and Met-Zn respectively were 1:3(L8),1:1(L9),3:1(L10).2 The results of experiment.2.1 Effects of different zinc source and levels of zinc on PH value and NH3-N density in rumen fluid.There was no significant influence when added the diet supplemented ZnSO₄, Met-Zn and the mixture composed ( ZnSO₄, Met-Zn) on PH value in rumen fluid. diet supplemented ZnSO₄, Met-Zn and the mixture composed ( ZnSO₄, Met-Zn) all decreased the rumen NH3-N density after feeding 6-9 hours.but have no significant different after feeding 12 hours (p>0.05). The study showed that different zinc source supplemented to diet in certain time scope will reduce CP degeneration rate and increase N quantity ingested by rumen microorganism. VFA density difference of every group was remarkable (P<0.05). the control group was topmost, next Met-Zn group and mixture composed, ZnSO₄ was lowest.2.2 Effects of the dairy cattle rumen effective degration on the major nutrition ingredient Added Different Zinc Sources and Levels DietsThe rumen ED of the major nutrition ingredient were increased by supplement ZnSO₄, Met-Zn and the mixture composed by two zinc source( ZnSO₄, Met-Zn) to the diet.The rumen DMD,CPD,CFD of the diet supplemented with ZnSO₄(40mg/kg),the mixture(the proportion of the ZnSO₄ and Met-Zn were 1:3,3:1) increased.Synthetic evaluate the effects of the rumen ED,this experiment indicated that the best zinc source and levels of zinc was ZnSO₄(40mg/kgDM),then were the mixture(the proportion of the ZnSO₄ and Met-Zn was1:3),and the level of the mixture is 100 mg/kgDM.2.3 Effects of different zinc source and levels of zinc on the digestibility of major nutrition ingredients of diet.ZnSO₄ had part in increasing NDF digestibility. Different levels of Met-Zn had different part in increasing the digestibility of major nutrition ingredients of diet.The results of digestibility will be the best if supplemented Met-Zn(40mg/kgDM).The mixture (the proportion of the ZnSO₄ and Met-Zn was1:1) to diet,it will have part in increasing CF digestibility of diet.2.4 Effects of different zinc source and levels of zinc on cattle blood and mineral substance metabolism of the wool.The density of blood zinc,blood calcium,blood phosphonus and alkalinity phosphatase were in the normal range while the diet supplemented with different zinc source and there were no significient influence.There were significient influence on different zinc source and levels of zinc about wool zinc content .The wool zinc content,the group of Met-Zn> the group of ZnSO₄>contral group.There were no significient influence to wool zinc content,in condition of diet supplemented with the mixture (the proportion of the ZnSO₄ and Met-Zn were 1:3,1:1,3:1),but obviously higher than the wool zinc content of control group.In the same leves of zinc ,there were no significient influences between the group of diet supplemented with the mixture (the proportion of the ZnSO₄ and Met-Zn were 1:3,1:1,3:1) and the group of diet supplemented with ZnSO₄(40mg/kgDM, 100mg/kgDM, 300mg/kgDM),but had enhanced tendency.In conclution,the suitable levels of zinc increased wool zinc content, Met-Zn was better used than ZnSO₄ and the mixture(composed by ZnSO₄ and Met-Zn) in the diet of the dairy cattle.