Ewes Biological Cycle and Target Body Condition Scores

By Dr. Rodney Kott & Dr. Lisa Surber, Montana State University

Ewes Biological Cycle:

  • Breeding (Flushing-2 wks prior to turning out bucks and breeding-generally 2 estrous cycles or about 34 days)
  • Gestation/Pregnancy (138 to 159 days-147 day average)
    • Early (first 15 wks)
    • Late (last 6 wks)


  • Lactation
    • Early (first 6-8 wks; peak milk production is at 3 wks)
    • Late (last 4-6 wks; in most cases after 10 to 14 wks lactation ewes are for all practical purposes dry)
  • Dry


Target Body Condition Scores:

The figure below shows the target body condition score for mature ewes throughout the production year.  The optimum feed and management strategy may not necessarily involve meeting the exact nutrient requirements of the ewe at each stage of production but is designed to achieve a balance in body composition over the production cycle.  Regardless of production system, producers should strive to have ewes around average body condition (condition score of 3) at breeding and increase slowly to an average body condition (condition score of 3.5) at lambing.  A ewe nursing twins during early lactation will normally not be able to consume enough feed to meet her nutritional needs and thus will lose body condition.

Achieving Target Body Condition Score:

Ewes should be assessed for body condiction score at multiple stages through the production cycle (weaning, breeding, shearing).  A good rule of thumb is one pound of supplemental (above maintenance requirements) grain fed daily for 30 days will achieve one condition score.  This varies depending on ewe mature size, diet, and many other factors.  In contrast to under condition, overcondition can be a problem.  Restriction of diet should be done over many months to achieve a slow condition loss.  Do not underfeed ewes during late gestation or lactation.


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