The Merino, although specifically developed as a wool-producing sheep breed, contributes significantly to prime lamb production. This makes the Australian Merino the most important genetic resource for both the lamb and sheep meat (mutton) industries in Australia. In addition, the contribution of wool and meat to the profitability of the Merino flocks is changing, as more value is being placed on carcase and reproductive characteristics. Even in traditional wool growing regions of Australia, and particularly Western Australia, the increased value of mutton has put extra pressure on prices that are paid for replacement sheep and on the mix of wethers to ewes.
There is a continuing change in emphasis among sheep producers nationally towards producing sheepmeat. This is evidenced by a younger Australian sheep flock, containing fewer wethers, a higher proportion of females and an increased proportion of crossbred and nonmerino breed sheep than a decade ago (Barrett, 2003). The Merino, however, continues to have a significant impact on the sheepmeat industry. For example, in WA, there has been little change in the proportion of ewes joined to Merino rams (78%), but similar changes in flock structure, indicating increased production of prime lambs from the Merino flock (Curtis, 2004).
Although growing in importance to the prime lamb industry, the Merino continues to be primarily selected for wool characteristics alone. Genetic improvement for carcase traits, disease resistance traits and reproductive traits requires knowledge of their heritability and the genetic relationships between these traits and wool traits. This information is just not available on the Australian Merino.
The Merino Validation Project was designed to fill these gaps in knowledge of genetic parameters and to provide Merino ram breeders with accurate information about a range of traits to actively breed Merino sheep that are profitable for both the wool and sheepmeat industry. The Merino Validation was an industry-supported project involving over 120 ram breeders nationally. The structure of the Merino Validation Project differs from previous investment in research and development in sheep genetic by funding bodies. Traditional investment has been primarily through research and demonstration flocks.
In this project, the data being collected came from on-farm measurements by breeders with key traits being measured through accredited procedures to ensure data consistency and integrity. Participants in the Merino Validation project continued to measure wool traits of their breeding animals, but in addition, were funded to measure carcase traits (fat and eye muscle depth), reproductive traits (scrotal circumference) and disease resistance traits (faecal worm egg counts).
The data provided by these industry flocks was sent to Merino Genetic Services to provide across-flock estimated breeding values for their animals. The data was also used to update the genetic parameter estimates used by Merino Genetic Services to allow for more efficient breeding programs for the ram breeding sector and better quality Merino genetics to be available for the commercial buyer.
Results from the project showed a wide range in breeding values for all traits. In the 2002-drop animals there is a range of almost 19 kg in yearling weight. This range was accompanied by a range of 10 mm of fat depth and 12 mm of eye muscle depth at yearling age.
The range of breeding values for wool traits were also large. These results indicated that there is significant genetic variation available for both ram breeders and ram buyers to utilise for increased rates of genetic gain in sheepmeat quality and quantity without loss of wool production. The Australia Merino can effectively be bred as a multi-purpose animal to suit individual breeding objectives to meet different market demands.