Calfhood Intranasal Vaccines
Intranasal vaccines can get past maternal antibodies.
Some herds have trouble with summer pneumonia in young calves, and bovine respiratory syncytial virus (BRSV) is the usual culprit. Generally, young calves don’t build much immunity when vaccinated young because of interference from maternal antibodies from colostrum.
“In these cases there are a couple of approaches,” according to Chris Chase, professor in the Department of Veterinary and Biomedical Sciences, South Dakota State University. “One is to use the intranasal vaccine. It has the ability to get around the maternal antibodies. The other thing a producer can do is use an adjuvanted vaccine. Most people think that only an inactivated vaccine is adjuvanted, but we do have some adjuvanted modified-live vaccines,” he says.
“We vaccinated young calves (which still had maternal antibodies) and challenged them with BVD several months later, and this protected them. We were trying to set them up to give protection for later challenges, such as weaning time,” says Chase.
“With a summer pneumonia problem, BRSV is usually involved. There’s no vaccine just for BRSV, however. You have to use the combination product containing BRSV-IBR (infectious bovine rhinotracheitis)-BVD (bovine viral diarrhea)-PI3 (parainfluenza-3 virus), even though at this age in calves BRSV is the only thing most producers are really worried about,” he says.
Proper diagnosis is crucial to know what you are dealing with, and what to include in a vaccination program.
“There are some tests now, using deep pharyngeal swabs and other ways to get material from deep in the back of the throat, for a more accurate diagnosis. With BRSV, a Q-tip swab from the throat is hit or miss. The deep pharyngeal swab gives better results,” he says.
“Some of the work we’ve done with inactivated vaccines shows that even after one dose of vaccine, we can see that some of the T-cells are turned on within two weeks of vaccination. We can see BVD antibodies, even after 14 to 21 days, which is exciting, because we generally don’t see much of a response when we vaccinate with just one dose of inactivated vaccine without following it with a booster. To use just one dose would be off-label because we don’t have enough data to say you’d be safe with just a single dose,” says Chase.
“In most production schemes, however, it may be hard to give calves a second dose. You may only have one opportunity to vaccinate them before spring turnout. In this instance you are stuck with using the things we know have that kind of label — that we can give a single dose and gain adequate immunity,” he says.
“At this point in time the intranasal vaccine will give the most likelihood of success and the least likelihood of failure in that age group. From two weeks up to three months, this makes the most sense, particularly if you are worried about BRSV. The adjuvanted modified-live vaccine, with a single dose, also has some usefulness, but I haven’t seen enough data yet in young calves with agents other than BVD. The intranasal vaccine, by contrast, has plenty of data to show that it works,” he says.
Editor’s Note: Heather Smith Thomas is a freelancer and cattlewoman from Salmon, Idaho.