Yes - thanks for the more detailed info, Squeasy, that's really good.
I was in fact just giving an easy rule of thumb for those that probably haven't got a thermometer and wouldn't feel happy about giving an intraperitoneal injection.
Also, I did stress "new born" lamb as once it's past @6 hours old it's chances of survival are not good, as Feldar says.
As for warming - yes that's important but I warm the lamb while I'm preparing the colostum and however cold it is, so long as it has some movement and isn't completely moribund, then stomach tubing will work.