Uz toksičnost bakar ima i esencijalnu ulogu u odvijanju životnih procesa. Razlike između esencijalnih i toksičnih koncentracija kod bakra su vrlo male. Iako je bakar u mnogim područjima zastupljen odgovarajućim količinama neka područja su manjkava ovim elementom.
Da bi se ispitao sadržaj bakra u hranidbenom lancu tlo-biljka-ovca, na području Nišićke visoravni su tijekom ljeta 2003. godine ispitani uzorci tla, paše i krvi životinja. Srednje vrijednosti bakra su u paši od 0,56 ppm u svibnju i 0,72 ppm u lipnju i indiciraju manjkav sadržaj ovog elementa. To potvrđuju i njegove koncentracije u krvi ovaca od 0,39 ppm. Iako je tlo sadržavalo 18,85 ppm (svibanj) i 20,01 ppm bakra (lipanj), zbog interakcije s drugim elementima kao što su Fe, Mo i S nemoguće je dati generalnu ocjenu o statusu bakra bez istraživanja spomenutih minerala.Besides its toxicity, copper has an important role in animal nutrition. The differences between copper toxicity and copper requirement are very small. Although copper is found in adequate amounts over most regions worldwide some deficient areas have been reported in scientific literature. In order to examine the copper status in sheep, during summer of 2003 it were collected samples of soil, plant and blood of sheep at Nišići plateau in Central Bosnia. The results indicated low copper content in pasture (0.56 ppm and 0.72 ppm in May and July, respectively). Low level of copper in blood of sheep (0.39 ppm) confirms this deficiency. Although the soil contained 18.85 and 20.01 ppm of Cu in May and June, respectively, due to interaction with other elements such as Fe, Mo and S it is impossible to give general opinion on the Cu status without studying them
