His comments are in direct response to the difference in scanning results achieved between vaccinated and unvaccinated sheep in several studies over the years. The latest data, from Vet Services Hawke’s Bay Scanning Database 2012, demonstrates this – see: Vaccination graph.
Not only have the studies shown the importance of vaccination, Smart said they had also identified a change needed in how campylobacter vaccination should be given if dosing hoggets.
If not lambing as a hogget, a two-tooth ewe should be given two doses – sensitiser and booster – pre-tup, four weeks apart. If consistently lambing hoggets, or intending to, these two vaccination shots need to be given to hoggets pre-tup, then a one-off booster pre-tup as a two-tooth.
Not only have the studies shown the importance of vaccination, they had also identified a change needed in how campylobacter vaccination should be given if dosing hoggets.
Smart acknowledges the vaccination manufacturer recommends all ewes receive an annual booster, but from an onfarm perspective, he doesn’t believe it is necessary for farmers to do this.
He said there was a general belief that natural challenge within the farm environment was enough to act as an immunity booster to mixed-aged ewes.
Jo Holter, spokeswoman for the vaccine supplier MSD Animal Health, agrees with Smart’s recommendation from a practical point of view but said that on some farms, where the disease challenge was high, boosting everything annually to help with control did occur.
Certainly where hoggets had been vaccinated, she recommended farmers give a booster the following year as a two-tooth.
For farmers wanting to “dip their toe in the water” and try hogget mating for a year or two, Smart said it probably wasn’t worth them changing their existing vaccination programme. They should just continue to vaccinate at the two-tooth stage until they decided they were going to continue to mate hoggets, then they could “shift” their vaccination programme forward.
Providing some insight into the disease, Smart said the two species of campylobacter that affected sheep were Campylobacter fetus fetus, common throughout the country, and Campylobacter jejuni, less common and mainly seen in the southern part of the country.
Regardless of where a farm is situated, he recommends all farmers use the vaccination that covers both these strains.
Where toxoplasmosis vaccination is given to hoggets, Smart said no further booster was needed unless the hoggets were not well-grown out and under 40kg pre-tup – both of which they should be if they were being mated.
