If you are looking for only IBR and PI3 immunity, intranasal is the way to go, as MLV intranasal vaccines give you a more direct immunity to respiratory viruses than an injectable. However, they obviously will not protect against anything they do not contain such as BVD. I will say that an IN BVD will be coming out from a different company that will (supposedly) have a better record than the prior one that was pulled off the market (Onset IN).