Effect of Source and Level of Dietary Supplementary Copper on In Vitro Rumen Fermentation in Growing Yaks

Copper (Cu) is essential for the health of livestock, however, optimal source and level dietary Cu yaks are uncertain. To fill this important gap, we designed an in vitro study to examine effects three sources, namely methionine (Met-Cu), chloride (CuCl2) tribasic (TBCC), at five levels, 5, 10, 15, 20 25 mg/kg DM (includes substrate), on rumen fermentation yaks. In dry matter degradability (IVDMD) amylase activity were greater (p < 0.05) with added Met-Cu than other two ammonia nitrogen (NH3-N), microbial protein (MCP) propionate contents CuCl2 TBCC. Total gas production lipase TBCC 0.05), which meant that metabolizable energy yield was former sources latter, but CH4 did not differ = 0.92) among sources. IVDMD greatest 15 mg Cu/kg substrate MCP, isobutyrate, butyrate isovalerate contents, trypsin activities or second 10 DM. It concluded best yaks, least under conditions.