SELECTED TRACE-ELEMENTS, VITAMINS, AND VIRUS-ANTIBODY TITERS IN MEXICO-ORIGIN STEERS

Serum levels of selected trace elements, vitamins, and antibodies to i nfectious bovine rhinotracheitis (IBR), bovine virus diarrhea (BVD), p arainfluenza3 (PI3), and bovine respiratory syncytial virus (BRSV) wer e determined in 100 Mexico-origin cattle upon their arrival in Del Rio , Texas. A majority of the cattle tested were found to be deficient in copper, zinc, and vitamins A and E; 92% had serum copper levels below the normal range, 54% were zinc deficient, 62% were Vitamin A deficie nt, and 75% were Vitamin E deficient. These multiple deficiencies may result in compromised immune responsiveness and increased predispositi on to disease. In addition, serologic results suggested susceptibility to multiple viral pathogens; 84% of cattle were seronegative for IBR, 64% were seronegative for BVD, and 24% were seronegative for BRSV. Th ese results should be helpful in designing preventive health programs for Mexico-origin steers.