Exploitation of embryos collected from Maedi-Visna seropositive ewes during eradication programs

It was demonstrated that Maedi-Visna virus is not transmitted through transfer of in vivo derived, either intact or micromanipulated sheep embryos, provided washing and trypsin treatment is applied immediately after collection. Thus, genetic material of highly producing Maedi-Visna seropositive sheep can be exploited or/and preserved prior to slaughter, (a) facilitating application of eradication schemes and accelerating flock replacement and (b) enabling preservation of genetic material (in the form of frozen embryos) from sheep of endangered breeds in cases when most or all available females are Maedi-Visna seropositive.