Ask the Vet
Advice to Vaccinate Bulls
READER: Do you recommend different vaccines for bulls than for cows? Is it OK to vaccinate at the same time as we do the BSEs on bulls?
DR. McMILLAN: I tell producers a bull is at least 25 times as important as a cow, assuming we use one bull to breed 25 cows. He could be more valuable if you use a higher cow/bull ratio, so proper care is extremely important.
Bulls and cows really need the same vaccines -- IBR (infectious bovine rhinotracheitis), BVD (bovine viral diarrhea), PI3 (bovine parainfluenza), BRSV (bovine respiratory syncytial virus) and five-way Lepto (leptospirosis). Many producers like to include vibrio (vibriosis, Campylobacter fetus) with cows and bulls, but in my experience in our area, this is a very uncommon disease. We do not have to worry about abortion in bulls, so modified live virus (MLV) vaccines are less of a concern. MLV vaccines can lead to fever in some cases, and fever can impact fertility. So, in a perfect world, bulls should be vaccinated 60 to 90 days before turnout.
The best bull vaccination program is to give two doses of MLV IBR, BVD, PI3, BRSV and five-way Lepto three to four weeks apart before or around weaning, and a booster at 12 months. This gets them off to a good start at a young age. With a solid immunity created early, any booster given prior to turnout will be more effective and should greatly reduce the chance of fever. While I still prefer an MLV vaccine, the quality killed vaccines should also be effective in these cases.
If you are unsure of the vaccine history of a bull, give two doses of an MLV IBR, BVD, PI3, BRSV and five-way Lepto. If vibrio is a concern, this vaccine should be done close to turnout. I believe Vibrin is the best vaccine for vibrio even if it only provides three to four months of protection.
Turning to vaccination at the time of the Breeding Soundness Exam (BSE), I am ecstatic you are doing BSEs. Many bulls are vaccinated at the same time as the BSE. I would rather have a fully vaccinated bull and cow herd than obsess over potential complications that may never occur. We do not live in that perfect world.
Vaccinations are very important in bulls, but other practices are also extremely important. No. 1 is a BSE for every bull, every year. Be sure the bull's body condition score is in the 6 to 7 range at turnout. Less than 6 can impact fertility, especially as the breeding season progresses, since most bulls will lose 1 to 2 scores. Bulls that are too fat can also be less-effective breeders. Very fat, soft bulls that "melt" when turned out can lead to a breeding disaster.
Good nutrition is critical to having a bull at peak performance at turnout, and that also means good mineral nutrition -- not just a salt block. Be sure your bulls and cows have access to a high-quality loose mineral all year long.
REFLECTIONS FROM KEN:
I was talking with a colleague who had recently retired from a long career as a clinician at Mississippi State University. We had started out in the same practice, but he was a few years before me. He asked if I thought we were delivering fewer calves than when I started in the early '80s. I told him we were, and there were lots of reasons. I'm afraid after COVID, there may be people who don't call us with emergencies. There may be more problems than we hear about.
As we talked, we agreed that we feel there has been an overall decrease in dystocias. The '70s and '80s saw the arrival of Continental breeds. These bulls were much larger and sired much larger calves. At least in the South, our cows were small compared to other parts of the country and certainly to our European counterparts. This mismatch in size led to lots of problems. As EPDs have improved, all breeds have been able to focus on calving ease, and seedstock producers have made great strides in this and other areas. Many of the smaller producers have disappeared, and the younger generation seems to do a much better job of heifer selection and development, which is also aided by EPDs. Let us know what you think.
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-- Please contact your veterinarian with questions pertaining to the health of your herd. Every operation is unique, and the information in this column does not pertain to all situations. This is not intended as medical advice but is purely for informational purposes.
-- These are only my thoughts and general guidelines. Please get with your veterinarian and together develop the best program for your herd.
-- Email Dr. Ken McMillan at vet@dtn.com
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