Trace Minerals for California Beef Cattle 

University of California, Cooperative Extension

Merced County Mineral Data

Random samples from 12 different herds (120 total head) had an average whole blood selenium level of 0.053 ppm. However, tremendous variation existed. Of the 12 herds, 5 were deficient, 2 were marginal and 5 adequate.

Deficiency was severe (herd average 0.02 ppm or less) for 5 of the 6 deficient herds. Herd average was below 0.01 ppm for 2 herds.

The adequate herds were 0.078, 0.110, 0.080, 0.106 and 0.129 ppm.

Herds in western Merced county tended to be more likely adequate, with selenium levels declining going toward eastern Merced county. Central Merced county tends to be highly variable with cattle in close proximity having large differences in selenium status. This probably reflects forage production practices such as irrigation with high versus lower selenium levels.

Operations will need to conduct individual sampling to ascertain their selenium status. Further work may help to identify areas by selenium status.

Cu status appears highly variable with both adequate and deficient levels in the county.  Serum levels from samples at the California Veterinary Diagnostic Lab (CVDL) averaged 0.75 ppm (SD 0.24) which alone suggests adequate levels.  However, liver samples, which are superior for diagnostic purposes, from CVDL averaged 155 ppm (SD 198).  This would suggest wide variation and the likelihood of some Cu deficiencies.  Thus, a marginal status is concluded, with the recommendation for further testing.

Samples from the CVDL averaged 1.46 ppm (SD 0.46) suggesting adequate Zn levels.  Additional samples would add confidence in that assessment.

Insufficient data are available for conclusions.