A number of members asked for advice on the correct dosage of vaccine for Ouessants, particularly lambs, which are significantly smaller than commercial sheep.
The recommended dose for Heptavac P-plus, the most commonly used vaccine, is 2 ml for sheep of all weights, from a 21-stone Charolais ram to a Ouessant lamb weighing just a few kilograms.
The Society therefore asked the vaccine’s manufacturers, MSD Animal Health, for their advice and have received this reply:
“We do not hold any data on the efficacy of Heptavac P Plus when administered at a smaller dose.
Therefore we would advise the use of 2ml per dose per animal (MINIMUM IMMUNISING DOSE) to obtain the immunity required.”
Clearly, and understandably without extensive testing, the manufacturer cannot vary the one-size fits-all advice. What do you think? Can our veterinarian members help? Do you vaccinate and in what dosage? Sounds like a topic for discussion in the forums or on the FB page.
NB: If you do choose to vaccinate using Heptavac P-Plus you should ensure all sheep receive two injections separated by an interval of 4-6 weeks and an annual booster injection thereafter. Pregnant ewes should be given their booster 4-6 weeks prior to lambing so that the newly born lamb receives some protection in its first few weeks of life.