Twenty-eight Brangus cattle were used to determine the effect of copper and selenium supplementation on performance and rumen fermentation. The animals were divided in: 1) (Control) - without supplementation of copper and selenium; 2) Se - 2mg Se/kg of dry matter as sodium selenite; 3) Cu - 40mg Cu/kg of dry matter as copper sulphate; 4) Se/Cu - 2mg Se/kg of dry matter as sodium selenite and 40mg Cu/kg of dry matter as copper sulphate. Animal weighing was performed in 28 day intervals, after 18 hours of fasting. Samples of rumen liquid were collected for analysis of volatile fatty acid and pH. The daily weight gain increased with selenium supplementation (P<0.05). The dry matter intake was not altered by treatments (P>0.05). The animals that received copper supplementation had lower pH rumen compared with selenium/copper supplementation (P<0.05). The animals supplemented with selenium/copper had a high proportion of acetic acid when compared to control (P<0.05). For propionic and butyric acid, there was no difference (P>0.05) among treatments. Despite the little effect on rumen fermentation, the supplementations of selenium, copper and selenium/copper provided better feed efficiency.
minerals; nutrition; ruminants; sources; volatile fatty acids
