Breeding Philosophy

The Mumblebone breeding program combines early maturity and high fertility with exceptional wool quality.


shearingThe Mumblebone sheep have been shorn twice a year since 2016.

The independent trial done by UNE on our ewes in 2019-20 showed a $30/hd increase in wool value from the ewes shorn at 6 months compared to the ewes shorn at 12 months.

This was achieved through:

  • An increase in fleece weight
  • A reduction in VM (vegetable matter)
  • An increase in SS (staple strength) &
  • An increase in yield.

We are currently growing between 62mm & 68mm of wool in 6 months.  Our target is 70mm in 6 months as this is a length that the carding buyers & the combing buyers can both compete on, making it the most sort after length on the market.

The trial also showed a 25% increase & a 33% increase in condition score when measured at pre lambing & weaning.

Important ASBV’s to select for are: Staple length (YSL) and curvature (YCURV)


The Wool

shearingWool quality is a feature of the Mumblebone sheep.

Since moving to 6 monthly shearing our stud ewes have averaged 4kg’s of 19.2micron wool every 6 months. Our flock ewes have averaged 3.4 kg’s of 19.4micron wool every 6 months. These fleece weights are from ewes that have been weaning 120-133% of lambs.

Wool quality is a very important part of the Mumblebone breeding program & our selection focuses on wool that is grown from a skin that is completely free of wrinkle. These soft, smooth, wrinkle free skins produce fibre that is very well aligned & very fast growing.  Fast growing fibres produce a deep, bold crimp pattern & a lustrous white sheen that doesn’t hold moisture & doesn’t attract flies. As a result, we no longer need to apply chemicals to prevent flystrike.

It is also essential to remove skin wrinkle from the sheep to be able to cease mulesing.

Important ASBV’s to select for are: Fleece weight (YCFW), fibre diameter (YFD) and co-efficient variation (YFDCV)


Carcass Traits

Muscle (EMD) and fat (FAT) are the two carcass traits we select for to increase condition score and build in the genetic energy reserve of our sheep.

shearing1kg of Muscle = 5mj energy.

1kg Fat = 37mj energy.

Sheep with genetically higher levels of EMD and FAT gain condition more quickly & take longer to lose condition when under pressure. This “haystack on the back” is particularly useful given the variations in feed quality throughout most years.

The ability for sheep to feed on condition when feed is “cheap” (or plentiful) creates the opportunity for them to then draw down that condition when feed is scarce. Conversely, sheep that have low levels of genetic fat and muscle are the first sheep to lose condition when under pressure and are the first sheep to lose wool cut or foetuses because they don’t have the energy to maintain them.

Muscle and Fat are essential traits in a modern merino flock.

Important ASBV’s to select for are: Muscle (YEMD) and FAT (YFAT).


“Without reproduction there is no production. An animal must be able to reproduce itself easily”


Selection for improved reproduction is a very valuable tool. Our aim is to conceive 160% of lambs and convert 90% of those foetuses.

All ewes are pregnancy scanned every year to identify the dry ewes, single bearers and multiples. All dry ewes are sold, maidens included, with no second chances.

Lambing twin bearers in small mobs (less than 100 hd) is aimed at increasing the foetus conversion ratio. We currently mark 175% of lambs from the ewes that conceived twins which is an 86% conversion of foetuses. Singles are converting 96% of foetuses conceived which leads to an overall marking and weaning rate of around 130% across the flock.

High conception rates and higher conversion of those foetuses simply means more lambs to sell. More lambs to sell means greater selection pressure at classing time and faster genetic gain.

Important ASBV’s to select for are: NLW and YNLW

Early Maturity

Early maturity is important for lamb survival, for wether lamb sales and for ewe lamb joining’s.


We target the domestic market with a 22kg carcass & aim to have our wether lambs sold at 6-7 months of age. The sooner they reach this weight the higher the margin.

Ewe lambs are joined at 7 months of age. Conception at this early stage is increased by combining heavier body weight with higher condition score. Joining ewe lambs is a wonderful way to:

  • Drive natural selection for early growth and fertility
  • Increase selection pressure at classing time
  • Reduce the age of surplus ewes

When managed according to their nutritional needs, the same ewe lambs continue to lamb the following year, displaying outstanding maternal instincts.

Important ASBV’s to select for are: WWT and PWT


All stud lambs are scored for temperament at Post Weaning.

A calm ewe has a greater chance of conceiving more lambs and is less likely to be frightened away from her lambs if disturbed. She will also burn less nervous energy when handled leaving greater energy reserves for milk, meat & wool production.

A calm temperament also makes the modern merino, which is now a much stronger animal, easier to handle in the yards and shearing shed.

Important trait to select for: Temperament score


Mulesing continues to be an issue for the industry, however, our position on the matter is very clear. We stopped mulesing our sheep in 2006 as our sheep no longer needed to be mulesed.

Important ASBV’s to select for are: EBWR and EBCOV