Read the manufacturer's label recommendations with regard to age/stage of production, AND when to give boosters(if it calls for one, and you don't give it in the appropriate timeframe, you've pretty much wasted that initial dose).
Inforce-3 contains IBR/PI3/BRSV; no one has been successful in developing an effective intranasal BVD vaccine that didn't have some pretty profound adverse effects/reactions. I like the Inforce-3 vaccine, and use it preferrentially over Nasalgen or TSV-2 as the initial viral vaccine in my pre-weaning protocol.
Thanks Lucky - I had it in my mind that it was IBR PI3 & BVD, so appreciate the correction. We haven't purchased any yet, but plan on using it - especially for show & sale cattle to "kick in" their immunitie system before trucking - instead of Nasalgen & TSV2.