Results
Of the twelve beef heifers that were experimentally infected, the calves of three heifers tested virus
positive by RT-PCR and antigen positive by ELISA in their serum prior to colostrum ingestion.
The calves from the remaining eight heifers tested virus negative and antigen negative and one heifer
aborted her fetus 253 days post-AI. The median ELISA S/P ratio for colostrum collected from heifers
carrying a PI calf were significantly higher compared to colostrum collected from heifers that were not
carrying a PI calf for dilutions of 1:100 (p < 0.05), 1:200 (p < 0.01), and 1:500 (p < 0.01) (Table 1).
For undiluted and 1:5 diluted colostrum, the median ELISA S/P ratio for colostrum samples collected
from heifers carrying and not carrying PI calves did not differ significantly (Table 1).