Commercial Benefits

Mumblebone rams are bred to combine early maturity with high fertility and exceptional wool quality.


Genetic differences in live weight reflect the growth potential of an animal.

Correlations of increased growth:

  • Higher reproductive performance
  • Marketable at earlier ages
  • Higher fleece weight
  • Higher lean meat yield
  • Increased fiber diameter
  • Mature weight goes up
  • Lamb birth weight goes up


Carcass muscling is reflected by eye muscle depth.

Correlations of increased eye muscle depth:

  • Higher reproductive rate in ewes
  • Higher worm resistance
  • Higher lean meat yield
  • Higher dressing percentage
  • Shifts lean meat from the fore quarter to the loin
  • Can reduce growth
  • Can reduce eating quality


Carcass fatness is reflected by the depth of fat between the eye muscle and the skin. Fat increases the ability of breeding ewes to maintain weight and condition in “tough” times.

Correlations of increased fat cover:

  • Improved reproductive rate
  • CV of fiber diameter goes down
  • Intramuscular fat (marbling) improves
  • Eating quality improves
  • Fleece weight can go down

Fleece weight

Correlations of increased fleece weight:

  • Body weight and growth go up
  • Staple length goes up
  • Fat goes down
  • Reproduction goes down
  • Higher fiber diameter
  • Increased wrinkle score
  • CV of fiber diameter goes up

Staple length

Correlations of increased staple length:

  • Fleece weight improves
  • Higher growth
  • Lower FDCV
  • Less fleece rot
  • Washing yield goes up
  • Reproduction can go down
  • Fiber diameter goes up

Yearling Coefficient Variation of Fiber Diameter

CVFD measures the amount of variation between individual wool fibers within a fleece.

Correlations of reducing FDCV:

  • Muscling improves
  • Fatness improves
  • Higher growth
  • Worm resistance improves
  • Less fleece rot/body strike
  • Higher staple strength
  • Fleece weight can fall

Yearling worm egg count

Correlations of Worm resistance YWEC:

  • Higher muscling
  • Higher staple strength

Early breech wrinkle

Correlations of lower wrinkle EBWR:

  • Higher reproduction
  • Less fly strike
  • Higher staple strength
  • Lower fleece weight

Yearling fibre diameter

Correlations of lower fibre diameter YFD:

  • Comfort factor improves
  • Lower fleece weight
  • Lower growth
  • Lower body weight
  • Lower staple length
  • Lower staple strength
  • FDCV goes up

Number lambs weaned

Correlations of Number of lambs NLW:

  • Higher body weight
  • Higher growth
  • Lower wrinkle score
  • Lower fleece weight
  • Lower staple strength

Correlations can be managed by selecting a balance of traits that suit your flock.