The benign March weather has been a godsend for many sheep units entering their peak lambing season, but producers must not become complacent if they are to gain full value from the new season lamb crop.
"So far the weather has been great for lambing and it’s gone well on many units," says independent sheep consultant Lesley Stubbings. "Early signs are that although we may not necessarily have had a bumper lamb crop, it’s a lot better than it could have been considering the arctic conditions that hit soon after many ewes had been put to the ram. The aim now is to keep those lambs healthy because with prices still firm, they are valuable assets. And losing lambs to easily preventable diseases this summer really is throwing money away."
Lesley Stubbings is particularly concerned about the threat of pneumonic pasteurellosis. "We could still have some wet and stormy weather, and sometimes this is all the stress it takes to cause a disease outbreak in unvaccinated lambs."
She points out that pneumonia continues to be a significant cause of death in unvaccinated lambs. "The disease can have a variety of causes, but many outbreaks are caused by pasteurellosis. Pasteurella are a group of bacteria, with Mannheimia haemolytica and Bibersteinia trehalosi being the most important types to cause disease in sheep. Flock problems usually start with sudden deaths, often in relatively young lambs. But occurrence can be sporadic in individual sheep."
She reminds producers that the colostrum lambs receive from the ewe shortly after birth only gives them protection for a limited time against pasteurellosis and the clostridial diseases like pulpy kidney, braxy, blackleg and tetanus.
"If ewes are vaccinated properly with Heptavac-P Plus in the run up to lambing then the lambs will also gain immunity from their colostrum. 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 four weeks and clostridia for up to 12 weeks. This means that some early season lambs may already be unprotected and at real risk from these prevalent disease threats unless they are vaccinated themselves. Don’t undo all the good work," she urges.
Lesley Stubbings recommends vaccinating finishing lambs with Ovivac-P Plus in at risk flocks, pointing out that the cost of one severe outbreak of pasteurellosis equates to many years of vaccine use for the average flock.
"The vaccine can be used from three weeks of age and the primary course involves two vaccinations 4-6 weeks apart. This immunity will last for 12 months, although lambs retained for breeding will need to be put on the Heptavac-P Plus system."
