Ewe BCS: Start now to ensure ewes are fit for the year ahead
Having ewes in the correct body condition score at mating will not only improve flock performance but will also make flock management for the year ahead easier, Dr Frank Campion of the Animal and Grassland Research and Innovation Centre tells us more.
Mating time for March-lambing flocks is only around the corner, with only 5 to 6 weeks left before the ram is introduced. At this stage, preparations should be well under way with cull ewes already identified. It’s important to keep a regular check on the ewes being retained for this year to ensure other problem ewes are identified, and issues are dealt with promptly to ensure all ewes selected for mating are fit and sound. A key component of this is getting ewes in the correct body condition score (BCS).
Ewe BCS is one of the most important metrics for measuring a ewe’s nutritional status and requires nothing more complicated than your hands and a sheep race/pen. Body condition in sheep is assessed by using your hand to feel along the sheep’s lumbar region between the last rib bone and the hip bone. The level of fat and muscle cover on four areas is assessed; the spinous process, the transverse process, over the ends of the transverse process and the fullness of tissue between spinous and transverse processes as displayed in Figure 1.
Figure 1: Feeling the tips of the spinous and transverse processes in the loin area
Ewes use their body reserves essentially as a sink and store for energy during the year; building up body condition when energy demand is low, such as between weaning and mating, and mobilising body condition when energy demands are high during lactation. Building ewe BCS takes time and management, but the rewards are evident in flock performance through improved pregnancy rates, litter sizes and improved lamb performance by increasing the ewe’s ability to reach her peak milk yield.
Reducing the number of below target ewes
It can take 8-10 weeks to put on one full BCS unit on a ewe. There, for flocks mating in early March, they are already inside this window. Typically when we talk about ewe BCS, we talk in terms of averages with the target for mating being a BCS 3.5.
However, another way to look at ewe BCS is by taking the approach to reduce the number of ewes below a minimum BCS target to as low as possible. For mating, this would be to have as few ewes as possible less than BCS 3.0. Flock owners should handle there ewes and rather than giving a ewe an exact BCS, they should be able to identify what ewes are thin and what ewes are ok.
In early August all the ewes in the Teagasc BETTER Farm Programme lowland flocks had their BCS assessed and on average ewe BCS was 3.1 ranging from an average of 2.8 to 3.4. However, the key figure from this was that on average just over 30% of ewes in each flock were less than BCS 3.0.
It is important to remember that at this time just because these ewes are thin, it does not necessarily mean they are the worst ewes in the flock. Some of the best ewes in the flock, in fact, will be thin after weaning as they will have mobilised body reserves into milk production for the lamb.
Identification and management
What is important with thin ewes at this stage of the season is that they are clearly marked and given preferential treatment in the run up to mating by grazing with the ewe lambs or fattening lambs not on concentrates e.g. grazing covers of 8-10cm down to 6cm and not being forced to clean out paddocks.
Marking these ewes is important as ewes that fail to regain BCS by mating should be culled, as it can indicate an underlying health problem. Alternatively, it can be an indication that she is unable for the system and will be a ‘passenger’ for the rest of the year, requiring additional feeding and management. All ewes regardless of BCS should be regularly checked and allowed to regain BCS in the run up to mating, restricting ewes or trying to remove BCS at this stage is not a good idea. Having ewes in the correct BCS at mating will not only improve flock performance but also make flock management for the year ahead easier.
More information
Dr Frank Campion joined Teagasc Sheep Specialist, Ciaran Lynch on a recent episode of the OviCast podcast, where he offered key tips on managing ewe body condition score in advance of mating.
Listen in below: