Why its important?
Body condition (BCS) is a good indicator of nutrition and health across your flock. By using BCS, you can adjust the flock’s nutrition to optimise productivity and reduce health and welfare problems associated with lean or overfat sheep. It can also be used as an indicator of when lambs are ready to go to market.
How to measure a BCS
To BCS, feel along the spine and assess how much fat is between the loin muscles. The BCS of ewes are usually scored between 1 (thin) and 5 (fat) but some people will simply use ‘fit’, fat’ or ‘thin’ as a guide to determine management.
Key scores
No breeding ewe should be in score less than 2.
Ewes in score 2.5-3.5 will provide optimum production and profitability.
Ewes that are too thin (<2.5) will have poor production, increased risk of mortality and poor reproduction.
Ewes that are too fat (>3.5) will have good production but stocking rate will be compromised which has a direct impact on profitability.
Assuming a unit of body condition score is equal to 10%-12% of a ewe’s mature liveweight; a 70kg ewe would need to lose/gain 7-8 kg to change a body condition score. This level of weight change will require careful management and time - normally taking around 6-8 weeks. It is important to get ewes in to a 'good' BCS plenty of time ahead of breeding to ensure top performance.
If ewes are BCS < 2 or resources are limited, supplementary feeding may be required. A very low BCS at weaning is likely to affect ovulation rates, even if the BCS target is achieved before mating. Timely identification of any other reasons for a low BCS, such as poor teeth, lameness or ill health is essential.
If an irreversible issue is found (e.g. poor teeth) then these animals should be marked and culled from the flock at the appropriate time. This can be done quickly and easily in the FlockFinder app!
Overfat ewes, BCS > 3.5 should be managed separately to ensure the target BCS is achieved. These ewes can have poor ovulation rates, poor colostrum and milk production due to the inefficient mobilisation of body condition and are higher risk for prolapse.
Stocking these ewes at a higher rate on lower quality forage or using them to clean out paddocks after other stock will help to gradually lose body condition. Careful management is required as attempting to slim ewes can cause problems with follicular development if they are subject to nutrition below their maintenance requirements in the last six weeks before mating.
The 'Ideal' Score
There can be some debate as to the 'ideal' score, which changes through the year. However, the following is usually the consensus across the industry.
It is worth bearing in mind that BCS is a subjective measure, so farmers will often score the same sheep differently based on their opinion, and differences in measuring approach.
So whilst BCS can be a useful guide to help manage your flock, it is only a guide. If you can aim for a score of roughly 3 throughout the year, then you won't go far wrong.
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