Optimum Ewe Condition

Key points:

  • Condition score merino ewe flocks now
  • The higher the condition score at joining, the higher the conception rate
  • Maintain ewes in same condition at joining through to lambing
  • Use condition scoring as a management tool to match available feed

Maintaining a merino ewe flock in average condition score (CS) between 2.7 or 3.5 will result in increased conception rates and decreased lamb and ewe mortality during lambing. Extra lambs on the ground, equals increased profits for your sheep enterprise. Using condition scoring as a means of matching feed source and ewe condition will assist in maintaining condition scores throughout pregnancy and lactation and ensures that the best feed is being utilised by the ewes that need it the most.

Condition scoring (CS) is a quick and reliable tool for managing the nutritional status of your ewe flock, especially leading up to mating and monitoring pregnant and lactating ewes. Figure 1 shows the ideal condition score targets of early winter lambing merino ewes in the cereal zone, though it should be noted that the actual ewe condition score profile during pregnancy can vary from 2.7 to 3.3 or higher.

The condition of a ewe at the time of mating can have a significant impact on lambing percentage. The higher the condition score at joining, (up to CS 4.5), the higher the conception rate. Lifetime ewe management research has shown that approximately 20 extra lambs per 100 ewes can be achieved due to a gain in an additional CS at the time of joining. Research has also indicated that the critical issue is to maintain ewes in the same condition at lambing as at joining. The optimum condition score from joining to lambing is 3.

Harvest, Christmas and holidays are a busy time of the year, but when you put your rams out, is an ideal time (or earlier if possible) to identify the condition of your ewe flock. Ewes can then be drafted into condition score mobs, and allocated appropriate stubbles, or supplementary fed to maintain their score during pregnancy.

Condition scoring your ewes before joining, will enable you to allocate your young and skinny ewes (less than CS 3) to your best stubbles. The end of January, and again in March, only about 50 ewes in each CS group need to be checked to reassess ewe nutritional status. Ewes can then be reallocated to other paddocks or hand fed, according to their condition.

Why waste paddock feed on fat ewes, whilst losing $ on your skinny ewes? Investing a few days of your time, could result in an extra 10% lambs weaned, and save on feed costs.

At weaning, your skinniest ewes are most likely to be your most productive ewes. Either they have reared twins, or produced large amounts of milk. If their lambs are weaned whilst there is still green paddock feed, they may pick up condition before joining. Identifying these ewes before joining, and monitoring their condition during pregnancy could greatly reduce lamb and ewe losses.

Why is condition scoring important? Maintaining a consistent condition score, above 2.7, during pregnancy results in:

  • Higher lamb survival at birth, especially twin lambs.
  • Increased lamb growth rate from birth to weaning
  • Increased secondary follicle development, resulting in lambs producing more wool, which is finer, throughout their lifetime. A 0.5 CS loss during pregnancy, reduces progeny clean fleece weight by 0.1kg per year, and increases fibre diameter by 0.2micron each year.
  • Reduced ewe mortality during lambing.