Breeding
Sires with a possible genetic make-up that are completely wool free in the crutch and inner hind legs may hold the genetic keys to breeding animals that do not need to be either mulesed or crutched.
The technology:
Research into breeding sheep with an enlarged naturally bare and wrinkle-free area around their breech is being conducted at two research centres, one in Western Australia (representing winter dominant rainfall areas) and a second in New South Wales (representative of summer rainfall dominant environments).
A number of animals have been identified with naturally bare breech and/or crutch that do not require mulesing or crutching.
Groups of sheep are being selectively bred for resistance to breech flystrike via wrinkle-free and/or bare breech area. Progress is monitored by comparison with a randomly selected control line.
Progress:
Early – “first generation” – results indicate significant potential to reduce breech wrinkle, increase natural bare area, and enhance resistance to breech blowfly strike.
Research has shown that the bareness traits:
- vary between animals from very bare animals to animals with a woolly breech and crutch;
- are moderate to highly heritable;
- did not have strong unfavourable correlations with other wool quality traits; indicating that selection for finer, barer high wool producing sheep is readily achievable; and
- can be transmitted to other flocks by using bare breech rams.
On-going research is looking at:
- whether bareness traits are expressed to the same degree in all genetic groupings and varying environments;
- how many genes affect the trait and how they are inherited; and
- precisely what correlations exist with the production and quality traits that impact on Merino profitability.
The January 2008 independent review by the AVA of AWI R&D on mulesing alternatives stated:
“The projects concerning the breeding of sheep that are less susceptible to breech strike have produced some very encouraging interim results.”
It must be stressed that there are a growing number of commercial and seedstock producers in Australia who have made excellent progress in this area.
Merino breeders have been breeding for reduced breech wrinkle for the last ten years. This is continuing at a rapid rate by both ram breeders and buyers.
Products that AWI has developed, which help woolgrowers select sheep for breeding that are less susceptible to flystrike are:
Sheep Genetics: In conjunction with Meat and Livestock Australia, AWI has developed Sheep Genetics. Sheep Genetics is the national genetic information and evaluation service for the wool and meat sectors of the sheep industry. It calculates the across-flock progeny breeding values for more than 40 key traits, including resistance to parasites.
Merino Superior Sires: In collaboration with the Australian Merino Sire Evaluation Association (AMSEA) and CSIRO, AWI has also produced another breeding product Merino Superior Sires. This annual report allows direct comparison of Merino sires evaluated at seven medium-wool and five fine-wool Central Test Sire Evaluation sites across Australia. It includes resistance to parasites traits.
Visual Sheep Scores guide: The first-of-its-kind pocket guide, developed by AWI and Meat and Livestock Australia, in consultation with industry, provides sheep and wool producers with a set of standardised visual scores – a new national language – to consistently describe, record and grade sheep for subjective traits. The visually assessed traits included in Visual Sheep Scores, include breech traits – breech wrinkle, breech cover, dag and crutch cover. This allows plain and bare breech sires to be better described to a standard and promoted to ram and semen buyers. Available free from the AWI Helpline 1800 070 099.