The next important job in most sheep farmers’ calendar is the yearly scan of ewes to check for pregnancy and lamb numbers, writes Andrew Sawyer.
This will let us know if the preparation and hard work up to tupping has paid off and give an indication of the lamb crop to be expected in the spring.
Scanning and splitting the flock according to nutritional needs is a very valuable management tool.
Knowledge of the number of lambs each ewe is carrying helps to ensure correct allocation of feed for the ewes leading up to lambing.
Too much food to ewes carrying singles will lead to big lambs, fat ewes and lambing problems.
Conversely ewes carrying twins and triplets will have higher energy requirements and it is important that they receive extra nutrition to prevent twin lamb disease and poor production of colostrum which in turn causes increased numbers of dead lambs.
For hill flocks, splitting singles to go back to the hill from twins that can be kept in bye and fed is even more important.
Aside from acting as an aid to managing the flock, the yearly scan can provide more information on flock performance.
Patterns in pregnant and non-pregnant (barren) ewes in different groups can provide clues to the mating performance of individual tups.
Furthermore, disappointing pregnancy rates can give an indication of other problems that could have been affecting the flock in the autumn.
This can often be difficult to determine as we are trying to look backwards to the autumn to work out what may have affected the scanning results.
For example, it is hard to ascertain the condition of the ewes at tupping three months later when things may have moved on – and poor condition often has a significant influence on conception rates.
However, there are investigations it is worth doing now to address some potential problems.
Poor scan results can be a result of toxoplasmosis or Border disease infections.
Blood sampling of a group of the barren ewes for antibodies to these can help identify if this is a problem in the flock.
Liver fluke is also known on some farms to play a significant factor in reduced conception rates.
Samples can be taken for fluke eggs to check for adult fluke in the flock.
We can now provide this service in our own lab rather than having a prolonged wait that previously accompanied samples being sent to an external lab.
Now is often the time for a mid-winter fluke treatment preferably with Closantel to try and preserve the effectiveness of Triclabendazole for the autumn.
Please speak to one of the farm team to ensure you are using the correct product for the time of year.
With poor scan results it may also be worth checking copper and selenium levels.
Low copper can lead to swayback in lambs – a congenital condition that causes severe limb in coordination.
Low selenium is a significant factor in reduced conception rates and can prevent new-born lambs from thriving.
As you can see, there is a lot to consider, and if your farm scanning results are not what you had hoped, please give us a call and find out what we can do to help.