TSV2 & Nasalgen are a great vaccine. We use it for our showstring also, for immediate protection against IBR & PI3. This is in addition to our normal vaccination program, using a MLV twice prior to weaning (of course, cows are also vaccinated with MLV prior to their breeding), and again later in the fall.
But, if your calf starts to get sick, you can squirt them with this nasal product & it kicks in their own immune system & they generally can fight off the bug without antibiotics. Love not having to give a SHOT! Prior to trucking to their first show, we sometimes give TSV2 to kick in thir immune system to avoid them getting sick from the stress.
Great product.