Here's one for starters:
http://avmajournals.avma.org/doi/abs/10 ... lCode=ajvr
Don't have another reference handy, but Dr. Cortese indicated that the IBR interference was a problem for Clostridial bacterin/toxoids, as well.
Disease pressures and management schemes vary widely across the country, and often are quite different even in small localities.
What works well or is absolutely necessary on one operation or in one herd may be inadequate or even overkill in others.
I have a closed herd with no fence-to-fence contact with other cattle. Only outside introduction in the past 25 years is a bull, purchased in 2006. I have minimal to no risk, with regard to IBR/BVD.
However, if you(generic) or your across-the-fence neighbor are constantly trading cattle, buying cattle at the salebarn, or traveling to and from shows... you might need to do more.
Granted, the sample I see on a regular basis is biased - they're submissions from producers who have a veterinarian regularly involved in their herd health program - or those who've finally taken a big enough hit in the pocketbook that they finally seek professional help. But...in my service area (mainly western KY, middle/western TN, SE MO, southern IL), I haven't seen a BVD abortion in 20 years; see an IBR abortion maybe every 5-10 years. Doesn't mean they don't happen - I just don't see them. Have never seen a viral abortion storm, much less one we could link to use of MLV vaccines. Rarely see Lepto abortions - haven't diagnosed one in the past year.
Is it because our producers are doing such a great job managing their herd health programs? I doubt it.
We're diagnosing Neospora abortion on an increasingly common basis - had a couple in my own herd this summer.
I do find BVD virus in close to 25% of BRD cases, so it's out there. We sometimes go decades without finding IBR or PI3 in BRD cases. Again, disease pressures are different in different parts of the country.
Steers and non-replacement heifers, slated for sale off our operation get two doses of Clostridial bacterin between 1&3 months of age. Pre-weaning, they get intranasal IBR/BVD/PI3 and Pasteurella/Mannheimia bacterin/toxoid. I think it's the right thing to do for the calf - and for the next person in the production chain - and, ultimately, for all of us in the beef industry.
Cows and replacement heifers here get only a 5-way Lepto HB twice yearly - and a Clostridial booster every 3 years or so.
Is that enough? For my operation, I think it's adequate - but may not be for others. Best to have a discussion with your veterinarian to assess your risk and needs.
