Genetics - Bare-breech rams opening frontiers
The search for alternatives to mulesing is seeing the progeny of bare-breech rams take part in two large-scale studies designed to understand the heritability of the trait and its effect on other production traits, and to map the trait to discrete regions of the genome in the world’s largest sheep gene-mapping project. On the genome front, Cojak was one of 20 rams being used to generate 5000 DNA-tested progeny in a bid to develop molecular markers that could fast-track future selection-breeding efforts. In addition, more than 100 other traits are being measured in a project that could go a long way to explaining variation among lambs for commercially important traits. The second project involves bare-breech rams that have been selected from different environments right across Australia. The five-year breeding trial will see each animal scored for bareness and wrinkle and joined to normal and bare-breeched ewes. The progeny will be tested for breech-strike resistance. In all, 600 ewes are involved at each of two sites: one in NSW, the other in WA. Throughout, each animal is being measured for production traits and monitored for flystrike. By the end of the trial, scientists hope to have a far better understanding of various breech traits and their heritability, their effect on lifetime production, and any potential management benefits of bare-breeched sheep.
Image: Cojak’s beautiful mutation: his legacy lives on.
See also: The inherent worm resistence of Merinos and Vale to a bare breech trailblazer.
Return to Beyond the Bale Issue 28 index page.