There has been lots of trial work over the years regarding vaccinations of calves and when is the most ideal time.
Immunologists debate this but as situations on farms changed and herds got larger, trends changed. Herd owners no longer boostered vaccines at four to six weeks apart, as was often recommended.
Summer pneumonias cropped up on young calves and these are often caused by the respiratory viruses such as BRSV (bovine respiratory syncytial virus) or the shipping fever bacteria such as pasteurella or mannheimia. Because it was always recommended the booster needed to be four to six weeks apart, producers left the initial vaccination to before weaning and then boostered it at weaning.
Older calves in the spring were given blackleg of course, as we knew for sure colostral immunity would wear off, but the other vaccines were left out.
Summer pneumonias increased in incidence and to try and avoid this during a time when calves were hard to spot and check, vaccination was initiated much earlier.
Even though the second booster shot was months later, producers noticed morbidity and mortality seemed lower. When immunologists looked, they found the booster response from the second vaccination (even though months later) was very good.
Over time they discovered that protection was good with many months between booster shots. This was great, as vaccinations could be more co-ordinated with other management procedures and in most cases did not require a separate pass through the chute. Whether it was weaning, implanting or deworming, the second shot of vaccine can be given at the same time as these procedures.
There was also a feeling there may be a maximum number of diseases or antigens calves could be vaccinated for at any one time. The analogy is the normal young animal — or human for that matter — is exposed to almost countless antigens on a daily basis and develops an immune response. It is very hard to overchallenge the immune system.
There was always the worry about vaccinating calves too young because of the blocking from colostral immunity. The calf ingests colostrum in the first few hours of life and the immunoglobulins in the colostrum contain antibodies against the diseases the cow has been vaccinated for or exposed naturally too. This blocks the humoral immune response of the calf.
What has only been discovered fairly recently is when calves were vaccinated at a very young age they were still protected many months out. This is what we call cell-mediated immunity. This also ties into when it is best from a management perspective to combine this with other procedures.
Many producers are calving later so calves are either born on grass in some cases, or go to grass at a very young age. The opportunity to administer protective vaccines is only at a very young age, otherwise the next opportunity to process calves is later into fall when they come in off grass.
If not vaccinated at a young age calves can be susceptible to the calfhood diseases, including the blackleg organisms. It is better to do it then, rather than leaving it till fall. Some companies are now testing their vaccines on younger and younger cattle. If we read the labels of many vaccines it will say not approved for use in calves less than three months of age. That is because at the time of approval those were the youngest calves the vaccines were tested against hence the recommendation.
I know for a fact there are companies where testing has been done on calves as young as three days of age, and others that have tested at a week old. In the foreseeable future it might make sense to be able to vaccinate calves as young as one day, while we process them with the shots at birth and apply their ear tags. That would save considerable labour and calves then have the ability to acquire protection against certain neonatal diseases right away.
The only dilemma with very young calves, if using modified live vaccines, is you need to use the low-dose bottles and group the calves together in multiples of 10 so you can vaccinate them all within two hours of rehydrating the vaccine. Some vaccines are made in individual doses and that helps. See what your vet advises as to the best vaccination protection for your young calves.
Vaccine-producing companies are using more and more intranasal technology, which is very easy to administer to inquisitive young calves and less stressful, as there is not the pain of a needle. These intranasal products are being tested on very young calves and that is a great indication of their safety. There are now a few intranasal vaccines for IBR PI3 one in which BRSV is also included. A brand new intranasal vaccine has just been released that works for the bacterial causes of pneumonia mannheimia and pasteurella and tested on week-old calves.
This allows you as producers to give protection for all the main respiratory pathogens except BVD in two intranasal vaccines. It eliminates giving needles to the very young calves and protection with the intranasal vaccines occurs very quickly (in about 48 hours).
Take advantage of the times you handle young calves as to whether vaccinations are warranted and check with your herd veterinarian as to which vaccinations they recommend for young calves in your area.
We always find the naysayers who have never vaccinated but all they need is a blackleg or respiratory outbreak to make them believers. Vaccination is still the simplest and effective form of biosecurity you can do for your cattle and will cut down antibiotic usage on young calves in most herds.
Happy calving… and remember to vaccinate.