Tuesday evening’s Tullamore Farm virtual event included a questions and answers session with MSD veterinary adviser Sarah Campbell focusing on vaccination.
Sarah highlighted that some lambs born to ewes vaccinated for clostridial diseases are still at risk of consuming insufficient colostrum due to difficult lambings, mis-mothering or insufficient milk yield. In turn, these lambs may not receive maternally derived antibodies and will need to receive the primary course for clostridial vaccination at a young age. Artificially reared lambs are typical candidates for suffering from clostridial disease. They face a higher risk due to the high volume of milk they are consuming and the risk of this overflowing into the small intestine and triggering bacterial growth and toxin release. There were also questions on the safety of discontinuing orf vaccination where no cases were identified in recent years. Sarah said great care should be taken if opting to discontinue vaccination, stating that if the flock was not free from any issues for a significant number of years then an outbreak could quickly occur where vaccination was doing its job and keeping a lid on issues.
The final area where a number of questions arose was in regard to identifying abortion-causing agents and in particular enzootic abortion and toxoplasmosis. She said the gold standard was submitting the foetus and foetal membranes for laboratory analysis. Where this opportunity was missed then blood sampling could pick up antibodies for exposure to the pathogen.
The optimum time frame for this task is about three weeks post-lambing. After this the presence of antibodies will start to wane and there is little merit in carrying this out after six weeks post-lambing.
In-lamb ewe hoggets
It is that time of year again where reports arise of ewe hoggets being drafted for slaughter showing up in-lamb and at an advanced stage. This can give rise to animal welfare issues as when these animals are rightly held back from being presented for slaughter there is a high risk of lambing difficulties due to the fact many have been on an intensive feeding programme. Where there is any doubt of sheep being in-lamb they should be scanned so that feeding programmes can be altered and plans put in place in advance of lambing.
The loss associated with this situation is even greater than normal given the high cost of hoggets at present. I have heard of situations in recent weeks where genuine farmers who sold hoggets have come good on taking the hoggets back or compensating the finisher for the loss in income where hoggets have been sold live at a lower price relative to their value for slaughter. There is unfortunately no hard and fast rule on this and it is down to the goodwill of the producer and a clear outline of dates to show when animals went in lamb.
A few questions on early weaning lambs have come in on the back of last week’s notes on creep feeding. Grass intake of lambs increases rapidly from six weeks of age on, rising from 0.3kg DM per day in week six to 0.5kg DM/head in weeks seven and eight followed by a further increase in intake to 0.7kg DM daily in weeks nine and 10.
Lambs can be weaned where they are consuming at least 250g/day concentrates on three consecutive days to reduce grass demand. There is typically one of two options utilised – offer lambs the best grass available along with restricted concentrate supplementation or transfer on to an intensive concentrate diet.