Eastern Shasta county has been extensively sampled for selenium levels in cattle. Samples (n=1905) from the Hat Creek, McArthur and Shingletown areas combined were 0.04 ppm whole blood selenium. The deficient level is 0.04 ppm so selenium supplementation should be responsive.

The Hat Creek area is especially selenium deficient. 383 samples averaged 0.014 ppm with the highest level at 0.078 ppm. The Shingletown area was also very deficient with samples (n=370) averaging 0.023 ppm. From the McArthur area more variation was found with an average of 0.054 ppm (n=1153), but some values were very low, 0.005 ppm. 

Limited samples from cattle in western Shasta county indicate selenium deficiency also occurs in that area.  Fourteen samples averaged 0.022 ppm from the Bald Hills near Ono, while 7 samples from cattle near Cottonwood averaged 0.014 ppm.

Cattle in Shasta county should be considered selenium deficient. 

Twelve samples from cattle in western Shasta cattle were about normal in copper, averaging 0.83 ppm in serum.  The lowest level was 0.63 ppm.  Pooled data from 123 samples submitted to the California Veterinary Diagnostic Lab (CVDL) showed an average serum copper of 0.78 ppm (SD 0.14).  These limited data suggest marginal levels of copper.  Tissue samples from liver for 22 samples submitted to the CVDL averaged 123 ppm (SD 113) with levels below 100 considered frankly deficient.      

Thus, additional sampling should be done for specific cattle, but copper is considered deficient to marginal.

Zinc

Twelve samples from cattle in western Shasta cattle were normal in zinc, averaging 1.73 ppm in serum.  The lowest level was 1.16 ppm.  Pooled data from 109 samples submitted to the CVDL showed an average serum zinc of 1.58 ppm (SD 1.18).  The large standard deviation indicates wide variation, and likelihood of deficient individuals.  

Further information is needed, but zinc levels are probably highly variable with some individuals deficient.  Sampling of individuals and herds is needed to determine specific zinc status

Phosphorus

Twelve samples from cattle in western Shasta cattle were normal in phosphorus, averaging 81 ppm in serum.  The lowest level was 61 ppm.  

Insufficient data are available for conclusions for cattle in eastern Shasta county.