Thursday, July 7, 2022

Increasing ewe body condition

“Does my butt look big in this?” It’s a loaded question that often confuses men into thinking an accurate assessment is wanted. Unfortunately many have been getting this wrong for generations.

Yet in the sheep yards, an accurate assessment of body condition can pay handsome dividends. Sheep farmers have been told for a number of years how an improved and consistent ewe body condition score has the ability to grow the bottom line.

John Scandrett, of Scandrett Rural Ltd in Invercargill, estimated the average ewe body condition score (BCS) three weeks pre-lamb in 2011 was probably sitting closer to two rather than where it would have been most beneficial – at between three to 3.5. He believes the good operators are achieving a constant flock average BCS of 3+ and although this is certainly achievable over summer, it is a “big ask” to maintain condition over winter. 

“Ewe and pasture management throughout the year has to be at a higher level and it doesn’t get any easier as time goes on as there is always a need to be planning ahead. Good operators tend to see what’s happening beforehand. To be a good pasture manager you need to be proactive rather than reactive.”

It is also important to aim for a narrow range around the targeted BCS as too much variation between the lowest and highest makes management of ewes difficult. Splitting ewes into two mobs, one higher and the other lighter, is considered best for ease of management. The lighter mob should realistically account for only 10-15% of the total flock. 

Several benefits can be achieved, as listed, by aiming for a BCS of between 3 to 3.5 but putting a financial figure to these benefits is difficult, although work is under way at AgResearch to try to quantify this figure.

Undoubtedly the largest gains stem from having lambs much heavier at weaning, allowing for increased weaning drafts to meat processors and fewer days needed to grow the remaining lambs. Cashflow is then improved, there are fewer mouths to feed and more pasture, allowing for increased flexibility during the summer and more scope around ewe nutrition management. Scandrett describes this period as providing a significant feed saving and encourages farmers to maximise it to get the full benefit.

“Whether you make the decision to carry higher stocking rates, or bring in extra animals over the summer to finish – use it to get the full potential, but make sure capital stock are fed adequately first.”

Post-weaning check-up

Making the decision to improve BCS begins about now.

Farm consultant John Scandrett said weaning was a good time to begin assessing sheep but it was a busy period. Get the ewes back in at some stage soon after weaning and sort them into two lines.

If ewes are being shorn soon after weaning it is possible to BCS by eye when straight off the shears. Otherwise it is a matter of feeling each ewe individually, using the touch technique, because wool obscures an accurate visual assessment.

Farmers who have yet to wean may want to make the most of the opportunity to get weight on to ewes during the late lactation period, considered an efficient time as milk production is slowing so any surplus energy she has will go into building condition. This is if pasture covers allow.

It is important to remember that when increasing a ewe’s body condition, her maintenance requirements will also increase. This is especially important over winter as a loss in condition can result in increased bearings.

Bearing problems

Consultant John Scandrett said many farmers in Southland reported a higher problem with bearings this year.

It was a common problem when going into autumn with good pasture covers, such as this year, and ewes were carrying extra condition. Scanning results are often higher, too, which can also affect bearings. The main two problems are an inability to maintain pasture quality, and not feeding ewes at correct maintenance rates.

Pasture quality cannot be maintained throughout winter if covers are too high at the end of autumn. Dead matter builds up in the sward so there is a limit to how much feed can be carried into winter, which effectively means grass does have a “use-by date”.

He recommends having some higher pastures for early winter grazing, and lower pastures for later grazing, which will have had time to come away slowly while preserving quality because dead matter doesn’t build up.

Longer pasture covers late in winter can appear good but the quality is not there and heavy in-lamb ewes lose condition extremely quickly.

The other trap farmers can fall into is routinely underfeeding ewes over the winter. If ewes are in better condition at autumn, then winter feed levels must be increased to allow for a heavier bodyweight and to maintain this condition. Condition loss over winter has been observed to be a major factor on some farms in predisposing ewes to bearing problems.

Tips for improving ewe BCS:

  •  Sort flock into heavier and lighter lines and preferentially feed lighter ewes
  •  Know each line’s average BCS at weaning, work out what it needs to be at mating
  •  Plan your summer pasture management from weaning onwards to achieve the weight gain needed
  •  If ewes spend more than two days in a block to get pasture control it is too large
  •  500 head/ha is the magic number – the stocking rate is high enough for the pasture to be cleaned up reasonably quickly without the intake of poorer quality feed being detrimental to stock
  •  You will make more money from electric fencing in the summer than you will in the winter
  •  Work out which paddocks are highest in clover – these are lamb finishing paddocks so manage them to maintain quality
  •  Use paddocks with lower clover content and older pastures for ewes, but too many seed heads and they will lose condition. They are also likely to lose condition if set-stocked for too long on this type of feed
  •  Ewes grazing older pasture with lower covers and seed heads will be able to eat more if they have access to water
  •  Some lighter ewes will build up condition when preferentially fed in a light mob then struggle to hold it when back in the main mob on correct maintenance levels. Cull them as not competitive and likely to be repeat offenders. High probability their progeny will have similar issues
  •  Lighter ewes tend to lose condition faster, which predisposes them to bearing issues
  •  If you have short covers going into lambing, you will be short through to weaning.

 Benefits research says you can expect from a BCS of 3+:

  •  Increased scanning through increased ovulation/fertility
  •  Improved ewe lambing % from improved scanning and increased survivability
  •  A significant reduction in bearings
  •  Increased ewe colostrum (up to twice as much)
  •  Increased overall milk yield (up to 80% more)
  •  Lambs weaning at increased weights
  •  More off to meat processors at weaning
  •  Fewer days needed to grow remaining lambs post-weaning
  •  Fewer animal health costs
  •  Improved cash flow
  •  Increased ewe wool production and quality from better nutrition
  •  Ewe lamb progeny producing up to 11% more lambs as adult ewes
  •  Improved hogget lambing % from ewe lamb progeny reaching mature weight earlier.

 What’s involved:

In the short-term there will need to be a focus on increased assessment and management of:

  •  Existing pastures
  •  Pasture renewal programme
  •  Fertiliser strategies
  •  Feed planning
  •  Ewes
  •  Mob management
  •  Body conditional scoring of individual animals at least twice a year (weaning, pre-tup).

 

 Note: As knowledge is gained and strategies are adopted, assessment and management practices will become automatic.

Refer to Heartland Sheep (October 2012) for winter grazing management advice (p 114) and the touch technique to body condition scoring of ewes (p 108).

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