If a cow has been previously vaccinated against or exposed to a particular bug then there will be specific antibodies for that bug in her colostrum.
Providing a calf gets sufficient quantity of high-quality colostrum as early as possible after birth there are a number of calf-hood diseases that can be managed or prevented via the passive transfer of antibodies from the first milking colostrum to the calf in its first 24 hours of life.
Many vaccines require a priming shot and a booster shot to provide high levels of protection or antibody production and most of the vaccines that we use for colostrum protection of calves fall into this category.
For that reason, we need to begin planning our preventative herd health strategies about10 weeks before the next anticipated calving if cows have not been previously vaccinated.
For previously vaccinated cows, drying off is the time to give their ‘booster’ shot to maximise antibodies for the colostrum.
I have a loose basic rule around vaccine booster timing that is “who are you trying to protect”?
If trying to protect the calf, boost the cow at dry-off. If trying to protect the cow or the staff (for example, with botulism or 7-in-1 vaccine) then I simply do an annual booster according to the calendar. And if I’m trying to protect a pregnancy (for example, BVD or Vibriovax) then I plan my boosters to be just prior to joining but obviously we should always follow the guidelines provided by the manufacturer.
When I start working with a new client, I almost always recommend vaccinating the cows and heifers prior to calving with Scourshield to help protect calves from rotavirus, coronavirus and E.coli infections — because even on farms where there has been no previous problems with rotavirus recorded, sometimes this is because no diagnostic samples have been collected from sick calves.
The reason why I am keen to provide colostrum antibodies for rotavirus in particular is because when faced with a rotavirus outbreak in the middle of a calving period there is very little else you can do to treat a viral infection other than provide good nursing care and electrolytes. So if an outbreak occurs there is no good way to prevent further infections until the next calving period.
Rotavirus is an infection that severely damages the gut lining and in my experience it is often involved in mass mortality outbreaks either working alone or more particularly in conjunction with salmonella or cryptosporidia.
So finding a herd in the middle of an outbreak, with few options for preventing new cases, is not a pleasant experience for anyone involved.
The other diseases that I commonly vaccinate for include salmonella and some respiratory outbreaks.
Salmonella vaccination with either Bovillis S or Salmonella BUZ vaccines is usually based on a previous salmonella “experience” on the farm and it is important that diagnostic samples have been collected and tested so that we can identify the correct strain to vaccinate against because the vaccines are strain-specific so it is important that the correct vaccine is being administered.
Respiratory vaccines against MH and IBR can be given to the adult cows prior to calving and provide some protection against respiratory disease in calves via the colostrum.
The critical factors that influence the success (or otherwise) of colostrum vaccine programs are:
- The correct timing of the vaccines to ensure that the antibody levels are at their peak to coincide with the cow making colostrum in her udder.
- Ensuring the dry cow and transition cow nutrition and management is sufficient for her to produce good quality colostrum.
- Dry cows are managed to prevent leaking of milk pre-calving.
- First milking colostrum is milked from the cow as soon as possible after calving, ideally within 12 hours into spotlessly clean test buckets and handled and stored correctly so it does not spoil.
- The colostrum MUST be fed to the calves as soon as possible after birth by teat or tube while the calf is still able to absorb the antibodies directly into the blood stream.
Also remember that colostrum vaccines alone cannot prevent disease unless other risk factors like hygiene, nutrition and immune system stressors are addressed as part of a proactive herd health plan
Now is a great time to discuss your vaccine program with your dairy veterinarian to ensure that there is adequate time to prepare the cows and heifers for an upcoming spring calving peak.
Dr Rob Bonanno is the regional ProDairy lead for Gippsland and northern Victoria.
