When to vaccinate?
From the information previously provided in this package, the approach to vaccination for most sheep producers should be relatively straightforward. It is a matter of assessing the likely occurrence of a disease, and in most cases, if a disease is likely to occur, even occasionally, then vaccination will be worthwhile. The higher the rainfall, the more common disease problems occur (botulism and tetanus may be exceptions).
It is also important to understand when to vaccinate.
At lamb marking, it will be prudent to vaccinate all lambs with 6-in-1 and where ovine Johne’s disease is present, Gudair® as well. Scabby mouth vaccination (scratch) should also be considered, and erysipelas vaccination may be warranted.
At weaning (generally six weeks after marking), any lambs not being immediately sold should receive their booster 6-in-1 vaccination (and booster erysipelas vaccine if needed).
For ewes (assuming they have been vaccinated as lambs), a pre‑lambing 6-in-1 booster vaccination and an erysipelas vaccine should be considered. Remember, the pre-lambing vaccination has to occur at least two weeks prior to lambing to give time for antibody production and incorporation in the colostrum, but it can be administered well before that and still give effective colostral levels.
Yarding ewes close to lambing to vaccinate can increase the risk of foot abscesses in wet environments and subsequent pregnancy toxaemia. Vaccinating ewes anytime in the previous six months should act as an annual booster so consider what timing is best. Ewes will initially require two doses of an erysipelas vaccine if protection for arthritis is required and marking and weaning doses have not been given.
In addition, consider vaccinating maiden lambs/ewe hoggets at their first joining (two doses required) to protect against loss from campylobacter.
Trace elements in vaccines
Some vaccines are available with trace elements added, for example, selenium or vitamin B12. This is useful if lambs at marking need these trace elements, but not for other sheep. A vaccine is given on an animal basis, not a weight basis (i.e. 1ml dose to a 10kg lamb at marking and a 1ml dose to a 60kg ewe).
Trace elements are given on a per kilogram basis, and so the rate of trace element provided in vaccines is usually only sufficient for lambs at marking.
If you purchase sheep directly from another producer, and you can get accurate information on previous vaccinations given to the purchased sheep, this may allow you to determine what future vaccinations are suitable.
However, if you are uncertain about the previous vaccination history, do not assume purchased sheep have received vaccinations. There may be some information provided on an animal health statement or the vendor declaration, but given the usually high returns from adequate vaccination, it is usually best to assume the animals have not been vaccinated, and start a suitable vaccination program for your enterprise.
Gudair® vaccination history may be indicated on the tag (with a V), and knowing the Gudair® vaccination history is important when buying sheep that are going onto likely infected properties.