My understanding was that Toxo required cats to complete the sexual phase of its life cycle which led me to mention of cats and feed (clearly contamination of the feed with cat faeces was less likely in your case unless done in the clamp, on the silage at pasture or on pasture itself). I take your point about vermin etc carrying aborted materials from place to place.
For those who are interested I've taken the following from Merck which is very handy for animal disease information in general:
"if ewes contract the disease late in gestation, abortions or perinatal deaths occur. Ewes do not usually appear sick. In an outbreak, there is usually a wide range in gestational age of aborted fetuses. In most cases there are no gross lesions, but in a few cases there are distinct small white foci, 1–3 mm in diameter, in some cotyledons. Fetal serology may also be used. Once infected, ewes are immune, so running unbred ewes with aborting ones may allow them to develop immunity. Preventing contamination of feed by cat feces may help reduce exposure. Toxoplasmosis is a zoonosis"
Good luck with your first day back tomorrow