Nearly all of the Teagasc BETTER Farm hill sheep flocks have finished pregnancy scanning in the past couple of weeks and overall the scanning rates and litter sizes are quite good, as presented in Table 1.
Pregnancy scanning is a very important management tool for all sheep farmers and this is the case for hill sheep farmers as much as lowland sheep farmers.
By knowing the litter size, it allows for singles and twins to be divided and managed separately, but it also can identify problems with pregnancy rates, particularly if the problem occurs over a number of years.
For the BETTER hill sheep farms, pregnancy rates this year are good across nearly all the flocks, with the exception of one where nearly 25% of the ewes scanned empty.
High levels of empty ewes can be attributed to a number of issues, such as poor ewe body condition at mating or a ram with fertility issues, particularly where single sire mating is carried out.
On the farm in question, ewe condition and mating management appear not to be the issues, as both were well managed, with raddle marks from rams at mating indicating a low level of ewes repeating after the first cycle.
As a result, the farmer’s local vet has been brought in on the issue and blood samples have been taken to investigate any potential underlying issues that may be causing the problem.
Higher litter size
The scanned litter sizes are good across the flocks and are ranging from 1.3 to 1.5, which are high levels of output for hill flocks.
Ideally in hill flocks we are targeting a scanned litter size of around 1.2 to 1.4 (ie more singles than twins) and a weaning rate of greater than one lamb per ewe joined to the ram.
In most cases, these levels of output are best suited to maximising the return from hill flocks, as it allows for more sheep to be returned to the hill after scanning and returned quicker after lambing.
A couple of the flocks in the programme are seeing scanned litter sizes a bit higher than what we are targeting.
This is most likely as a result of improving the grass supply on the green ground, while still building ewe numbers to match, meaning ewes are spending too much time on the green ground.
The solution for this on these flocks is to allow the ewes to spend more time on the hill while still monitoring ewe BCS and liveweight to ensure ewes are in the correct body condition throughout the year.
In some cases, the improvement in grass supply on the green ground will allow them to run a smaller, high-output lowland flock on the green ground to utilise the extra grass produced, while still ensuring there is enough grass available to allow the hill flock perform to its optimum.
This can take a number of years to achieve though and a slightly high scanned litter size is still better than having ewes too thin and having a low pregnancy rate, as thin ewes bring their own issues.
With scanning completed, attention turns to how to manage these ewes in the run-up to lambing.
For most of the flocks, the singles have been returned to the hill after scanning until closer to lambing, while twins will be held either on improved, enclosed hill or green ground where available.
Due to the nature of the flocks in the programme, some will house hill ewes carrying twins closer to lambing, but a key target for these flocks will be to get to a stage where all hill ewes are lambed outdoors.
Where single-bearing ewes are thin, they will be held back, with twin-bearing ewes to ensure more body condition is not lost in the run-up to lambing.