Evaluation of Selenium and Molybdenum in soils and grasses of two cattle farms of Puerto Salgar (Cundinamarca) and its possible effects on livestock

The problem of selenium and seleniferous soils and its effects on animal and human population are quite well known in Colombia since Colonial times. Its doesn't happen the same with Mo and molibdenosis, an element and disease which effects are so serious or worst than those of Se, which in this investigation we assume caused by the same cretaceous sediments (Villeta Group) which traditionally has been recognized only responsible of the formation of seleniferous soils and toxic vegetation. To prove the foregoing hypothesis and as a contribution to the knowledge of the origin and effects of Mo problem in Colombia, the soil and grasses of two cattle farms of Puerto Salgar (Cundinamarca, Colombia): La Gloria and Candilejas, both located in the border of two streams recognized as carriers of seleniferous sediments coming from Villeta Formation were analyzed. The water and sediments of three recognized seleniferous streams of the area were also analyzed. In all samples Se and Mo total content were determined. As a general conclusion Se and Mo content in soils and grasses in both cattle farms could induce variable degree of intoxication on animal and human population. In La Gloria's farm Se content in soil was 11 ppm in sites close to the river's border (0-60 mt) and decrease to 2.17 ppm in farthermost sites (268 mt). In Candilejas's farm Se decreases from 5.6 ppm in closer sites to the river's border (0-130 mt) to 2.63 ppm in farther sites (296 mt). In La Gloria's farm Mo decreases from an average of 3.40 to 4.55 ppm in the closer sites, to 1 ppm in those farther. In Candilejas's farm Mo decreases from 4.64 ppm in sites near the river's border to 0.15 ppm in farther sites. In both farms Se content in Angleton grass (Dichantum aristatum) samples was 0.8 ppm, Mo instead fluctuates around 9 ppm in those samples taken next to the river's border and decreases to an average of 3 ppm in samples taken farther from border. Average content of Se and Mo in all three stream sediments was 4.3 ppm but the individual highest values (6.12 and 7.56 ppm respectively) were obtained in Rio Negro's sediments. In both cattle farms were detected acute Se and/ or Mo intoxication cases in bovines