Effect Of The Form And Levels Of Copper On Production Performance And Nutrient Digestibility In Dairy Cattle

Twenty-seven dairy cattle were allotted to nine groups of three cows, according to calving date, lactation number and daily milk yield, to study the effect of the form and levels of copper on production performance and nutrient digestibility. Nine treatments were basal diet supplemented copper sulfate, copper methionine, rumen-by-pass-copper at the level of 8mg/kg, 16 mg/kg, 24 mg/kg per kg diet respectively. Twenty-seven dairy cattle were allotted to nine groups of three cows, according to calving date, lactation number and daily milk yield, to study the effect of the form and levels of copper on production performance and nutrient digestibility. Nine treatments were basal diet supplemented copper sulfate, copper methionine, rumen-by-pass-copper at the level of 8mg/kg, 16 mg/kg, 24 mg/kg per kg diet respectively. Four steers with permanent rumen fistula were elected to make digestion trial according to 4X4 latin square designment. The effect of different level of cupric sulfate, cupric methionine and rumen by-pass copper on the digestability of the nutrient at the base of 1.3 maintenance requirement.The results showed that:(1)The effect of 24mg/kg cupric methionine was the best significant. The milk yield, milk protein and milk copper were improved. The somato number was decreased after the supplement of copper. The mastitis could be prevented with the supplement of copper.The feed efficiency was improved. The first was 24mg/kg cupric methionine, second 16mg/kg rumen by-pass copper.(2)The digestability of CP, NDF, ADF, N, Ca and P was significantly increased. The 24mg/kg cupric methionine was best. The digestability of CF, CP, OM, NDF, ADF of supplement groups was significantly higher than Omg/kg (P<0.05). The digestability of N was significantly improved 17.81%, 10.73% and 19.87%, respectively (P<0.05). The digestability of Ca was significantly improved 29.32%, 110.89% and 118.65%, respectively (P<0.05). The digestability of P was significantly improved 25.34%, 26.92% and 29.10%, respectively (P<0.05).(3)The serum index of 24mg/kg cupric methionine was best, and significantly higher than 0mg/kg (P<0.05).(4)The fitting supplement level of copper in dairy cattle ration was 16~24mg/kg.(5)As a result, the supplement of 24mg/kg cupric methionine was best, second was 16mg/kg rumen by-pass copper. Rumen by-pass copper was practical because it's cost was lower than cupric methionine.