Mineral status of sheep in the Paramo region of Colombia. II. Trace minerals

Abstract

Three sheep classes (pregnant-lactating ewes, lambs and yearlings) were studied to determine the trace mineral status of grazing animals from three sheep farms located in the Paramo region of the Cordillera Oriental in Colombia. At the end of the rainy season (May–June, 1987) and middle to end of the dry season (February, 1988), soil, forage, blood and liver samples were collected. Soil Zn and forage Co, Cu, Mn and Mo concentrations were affected by season ( P < 0.05). Soil Se and Mn concentrations were deficient during both rainy and dry seasons (100% and 54%, respectively). Forage Co and Cu were deficient (87% and 75%, respectively); but Cu was 94% during the dry season. Mo values were below the toxic limit for sheep of 6 ppm, and the Cu:Mo ratio was at least 4:1. Fe and Mn were in excess of requirements for sheep but below maximum tolerable levels. Blood serum analyses showed only small deficiencies, liver for Cu (59%), Zn (44%), and for Co (55%) during the dry season. No differences ( P ≯ 0.05)were found among animal classes for any plasma and liver trace elements in both seasons. Ewes were more deficient in liver Zn (58%) and liver Cu (71%); yearlings in liver Co but lambs were about as deficient in liver Cu (69%) as ewes. Based primarily on liver analyses it was concluded that Cu, Zn and Co were the most deficient trace elements. These plus Se should be continually supplemented in the Paramo of Colombia. There was no direct relationship between soil and plant trace mineral concentrations, however, mineral imbalance problems in livestock could be predicted from forage and animal tissue analyses.