Study on the Controlled-release Boluses on Trace Elements for Ruminants and Their Metabolism in Rumen of Goat

Selecting five chemical as carrier or solubility-controlling medium and mixing them with copper(Cu),selenium(Se)and cobalt(Co).After melting at given temperature,molding into smooth surface boluses,which shapes were like ball or ellipse.The hydrolysis trial in vivo was conducted.The result showed that the mean released rate of copper,cobalt and selenium in the boluses were 7.33mg/kg, 0.33 mg/kg and 0.21mg/kg,respectively.After the hydrolysis trial,Each of three goats fitted rumen fistula were orally administered a initial bolus.Rumen contents and blood samples were collected from all goats to assay for copper,selenium,cobalt and volatile fatty acid(VFA).The results were as follow:after administering,the concentrations of Cu,Co and Se in rumen contents were 11.36mg/kg,0.73mg/kg and 0.14mg/kg,were 258%,385% and 244% higher than those of control;similarly,acetic acid,propionate and butyric acid were 33.91%,63.95%,20.53% higher than those of control,while blood copper,Selenium and cobalt concentrations were 24.25%,23.14% and 48.48% higher,respectively.The results showed that the technology of manufacture is feasible.The solubility of the boluses and released rate of trace elements were controlled.The released rate of the three trace elements can meet gosts'requirement.The boluses can promote the microbiobiology's active and increase output of VFA.