But this so called passive immunity only lasts for so long. Lambs that receive a good intake of colostrum only have antibodies against pasteurella for up to 3-4 weeks and clostridia for up to 12 weeks. This means that some early season lambs are now unprotected and at real risk from these prevalent disease threats unless they are vaccinated themselves.”

Drew McGurren recommends vaccinating finishing lambs with Ovivac-P Plus, pointing out that the cost of one severe outbreak of pasteurellosis equates to around 50 years of vaccine use for the average flock. “In the last 12 months, 2.8 million lambs have been vaccinated with Ovivac-P Plus as more farmers appreciate the importance of protecting these valuable animals. The vaccine can be used from three weeks of age and the primary course involves two vaccinations 4-6 weeks apart. An annual booster can be given thereafter, but most lambs are slaughtered before then or start on Heptavac-P Plus instead if they are to be kept as breeding animals.”
Source: stackyard.com