Assessing condition and focusing on thin ewes

Mating on the Teagasc BETTER Farm lowland sheep flocks is well under way at this stage, with ewes being joined with rams from 7 October for those targeting an early March lambing, while mating started up to last week for those targeting a later lambing.

Lambing date varies across the flocks based on the expected onset of grass growth next spring, so that flocks are lambing at a time that will allow them to maintain grass supplies in front of the flock next spring once grazing begins.

Another part of this is following an autumn closing plan, with the target being to have at least 20% of the farm currently closed for next spring and another 20% (40% in total) closed by the middle of this month.

Condition scoring

All of the ewes in the flocks were weighed and body condition scored (BCS) at mating time as presented in Table 1. The target is to have ewes at BCS 3.5 at mating time.

However, when we look at the average BCS, it can sometimes present a misleading picture as there will always be a range of BCSs within the flock.

Another way of looking at BCS that can give a clearer picture of what thin ewes are in the flocks is to look at how many ewes are less than BCS 3.0 at mating.

The target with this figure will obviously be to keep it as low as possible but nearly all flocks will have some ewes in the category that will need monitoring throughout the year.

In general, attention should be focused on under-conditioned ewes within the flock as these are most likely to cause problems compared to overfat ewes.

All of the flocks had a proportion of ewes with a BCS less than 3.0 with a range in these figures across the flocks.

Ewes are joined with the rams now and it can be very difficult to build BCS at this point and particularly when ewes enter the late pregnancy period. Therefore, the flocks will continue to monitor ewe BCS throughout the winter to try and at least get ewes to maintain their current BCS.

Thin ewes will be selected out for preferential treatment after mating such as potentially being housed earlier if grass supplies and utilisation rates drop. They will also possibly receive extra meal feeding once supplementation starts in late pregnancy.

During the mating period it can be tempting to just throw out the rams and forget about them until housing or scanning time. However, a bit of management at this time can make a big difference next spring.

All the flocks in the programme are raddling rams to identify the ewes they have mated and the raddle colour is changed regularly during the first three weeks of mating and less frequently after that depending on activity.

Changing the raddle colours will allow the flocks to identify if any rams are not working once the repeat cycle starts.

Raddling will also allow farmers to house ewes by expected lambing date and litter size, which will help to reduce feed costs in the spring. Being able to pen repeat ewes separately from ewes lambing in the first few days of lambing not only helps to reduce potential issues with oversized lambs but can also make a big difference in concentrate costs.

As an example, take a twin-bearing ewe receiving 1kg concentrates/day for the final two weeks pre-lambing with concentrate costing €450/t.

This ewe will consume 14kg during this time at a cost of €6.30 for the two weeks. If she is a ‘repeat’ ewe and is being fed from the same time, but lambs 17 days later, she will consume an extra 17kg at an additional cost of €7.65.

This means the ‘repeat’ ewe will have consumed €13.95 in concentrates v a potential of €6.30.

The flocks will also ensure rams are removed after five to six weeks of a mating period to ensure a compact lambing.

There can be a temptation to leave the ram longer but this will only prolong lambing and lead to extra work at an already busy time of year without any significant gains in the number of ewes lambed.

In 2022, all the flocks in the programme had lambing completed in 37 days on average with just under 90% of in-lamb ewes lambed in the first three weeks of lambing.

As presented in Figure 1 for a flock that had sufficient ram power, ewes in good BCS and where the ram was removed from the ewes after five weeks, 95% of the ewes were lambed in three weeks of lambing with an overall pregnancy rate of 95%.

By removing the ram after five weeks, it ensured all ewes were given two mating cycles with the ram and ensured lambing was finished quickly, so attention could be kept on managing the ewes and lambs at grass during a critical period of the year.