IN-VITRO FERTILIZATION OF OVA FROM COWS EXPERIMENTALLY INFECTED WITH A NONCYTOPATHIC STRAIN OF BOVINE VIRAL DIARRHEA VIRUS

Bovine viral diarrhea virus infection was induced in 16 heifers by inoculation of a noncytopathic strain of bovine viral diarrhea virus (BVDV). Six BVDV-free heifers served as controls. On Day 8 after inoculation, cumulus-oocyte complexes were collected from ovaries of animals at the second peak of fever preceded by leukopenia. The oocytes were then matured and fertilized in vitro. There was no significant difference (48% vs. 54% P>0.05) in the percentage of cleaved oocytes between infected and non-infected animals. However, the proportion of embryos that developed to the blastocyst stage was significantly higher for the control group than for BVDV group (29% vs. 14%) (P<0.01). All follicular fluids and cumulus-oocyte complexes collected from infected animals tested positive for the presence of the virus, but embryos produced by in vitro fertilization 7 days after in vitro co-culture tested negative.