The Effect Of Copper, Manganese And Iodine On Yak’s Rumen Fermentation, Blood Indexes And Growth Performance

In order to optimize yak’s feeding standard, the effect of three trace elements copper, manganese, iodine on growing yak’s rumen fermentation, blood indexes and growth performance was studied, so as to screen out the optimum adding forms and the optimum levels of trace elements copper, manganese and iodine in yak’s ration,and to design the formula of yak’s supplemental ration more reasonably. Eventually,the phenomenon of yak’s losing weight in winter could be prevented and the development of yak industry could be promoted.This experiment took advantage of single factor experimental design, and gas production, methane production, pH, NH3-N concentration, MCP content, DMD,AMS activity, LPS activity, TYS activity, CLS activity and VFA concentration were chose as determining indexes to screen out the optimum adding forms and the optimum level ranges of three trace elements copper, manganese and iodine in yak’s ration by gas production technology in vitro. The result showed that: the optimum adding form of copper, manganese and iodine in yak’s ration were copper mothionine,manganese mothionine and calcium iodate respectively, and the optimum level ranges of copper, manganese and iodine in yak’s ration were recommended as 10.0~20.0mg/kg, 40.0~60.0 mg/kg, 0.3~0.7 mg/kg respectively.According to the optimum adding level ranges of copper, manganese and iodine filtrated from gas production experiment in vitro, three trace elements copper,manganese and iodine were combined to research the optimum adding levels of copper, manganese and iodine in yak’s ration by live yak’s experiment. 18 three-year old yaks with similar body status were chose and divided into 3 treatment groups(five repeats in per group) and 1 control group(three repeats) randomly, and to proceed feeding experiment for 60 days(30 days’ preliminary feeding period and 30days’ formal experiment period). Treatment group Ⅰ: copper content was 10.0 mg/kg,manganese content was 40.0 mg/kg and iodine content was 0.3 mg/kg; treatment group Ⅱ: copper content was 15.0 mg/kg, manganese content was 50.0 mg/kg andiodine content was 0.5 mg/kg; treatment group Ⅲ: copper content was 20.0 mg/kg,manganese content was 60.0 mg/kg and iodine content was 0.7 mg/kg. Every yak was weighted before and after experiment to calculate the daily weight gain of yaks in each group; every yak’s blood was collected before and after experiment to compare and analyze the energy indexes, protein indexes, mineral substances and enzyme activity indexes in serum; every yak’s rumen fluid was collected from mouth after experiment to determine the parameters of rumen fermentation. The result showed that: the optimum levels of copper, manganese and iodine in yak’s ration were 15.0mg/kg, 50.0 mg/kg and 0.5 mg/kg respectively.