RESUMO
It has been reported that bovine herpesvirus-1 (BHV-1) remains associated with in vitro-produced (IVP) bovine embryos after exposure to the virus and either washing or trypsin treatment. However, it is not known if the quantity of virus associated with an exposed IVP embryo is likely to infect a recipient cow after transfer. The specific objective of this study was to determine if IVP embryos that were exposed to BHV-1 would infect uterine tubal cells (UTC) in a co-culture system. In vitro-produced Day 7 embryos were exposed to BHV-1 and then washed or trypsin treated according to the IETS guidelines. These embryos were then co-cultured individually or in groups with UTC in microdrops of tissue culture medium 199 (TCM 199) supplemented with 10% equine serum. Following co-culture for 48 h, virus isolation was attempted on the embryos and the UTC from each drop. Virus was detected in washed individual embryos, groups of washed embryos, groups of trypsin-treated embryos and the UTC co-cultured with each of these treatments. However, BHV-1 was not detected in the individual, trypsin-treated embryos or the UTC co-cultured with them. It is concluded that trypsin treatment might effectively prevent infection of recipients if individual, Day 7, exposed embryos were transferred into the uterus.
