- The genomc-based Flock Profile test was developed by team of researched from Sheep CRC, AGBU, NSW DPI and Sheep Genetics. The Flock Profile test is suitable for any commercial Merino breeder.
- When selecting rams for a commercial enterprise the first step is to set your breeding objective. Spend a few minutes to write down precisely what you are aiming for, including the levels of performance and by when you want to achieve it. Find more information on setting a breeding objective. Because the most effective way to select for a trait or characteristic is to directly measure or assess that characteristic, you should buy rams from a stud that objectively measures or collects scores (using a standardized system) for the traits you wish to improve. For instance, staple strength can be selected with much higher accuracy if the stud directly measures staple strength on its rams, rather than just having the ASBV calculated from related measurements such as fibre diameter coefficient of variation. However, the ram’s own performance is only part of the picture. What you see in the ram isn’t necessarily what you will get in the progeny because much of the ram’s performance is a result of the ‘environment’. Nutritional differences between animals are a key environmental element and not only come from what they eat, but whether they were born or reared as a twin or their mother was a maiden ewe—giving them less nutrition during pregnancy and lactation than for a single lamb and/or from a mature ewe. Also, climate, disease and management differences will affect how they perform. If you know these environmental factors for each individual, and if you have been able to inspect all of the animal’s relatives and see their performance data, you’d be able to predict very accurately, how the progeny will look and perform. However, this is not practical for you to do, so studs that provide you with Australian Sheep Breeding Values (ASBVs) already have this information taken into account. Pedigree information, management groups, data from relatives and relationships to rams used in the stud and elsewhere are all accounted for and very important when calculating Australian Sheep Breeding Values. Importantly, you can accurately compare rams from different studs (whether at opposite sides of the country or having had quite different management) if they both provide ASBVs for the same trait.
- Greasy fleece weight (GFW) Clean fleece weight (CFW) Fibre Diameter (FD) Staple Strength (SS) CV of fibre diameter (FDCV) Staple length (SL)
Consequences of Differing Wool Growth Rates on Staple Strength of Merino Wethers with Divergent Staple StrengthsAn experiment was conducted to determine the effects of dietary protein intake after a period of weight loss on the wool components of staple strength for sheep with a history of low or high staple strength (18.0 vs 34 Nlktex). After being fed to lose 15% of their liveweight over 10 weeks, sheep within each staple strength group were assigned in equal numbers to either a low or high protein diet designed to re-gain initial liveweight in 8 weeks. Liveweight, feed intakes and the growth, fibre diameter and fibre length characteristics of wool were measured at regular intervals. After the weight loss and growth regimes were imposed there was no difference in staple strength between the low and high staple strength groups (14.4 and 14.9 Nt ktex, respectively). However, coefficient of variation (CV) of fibre diameter remained significantly different between staple strength groups. Wool growth rate at the time of diet change was the only significant component of wool growth and fibre measurements that was significantly correlated with staple strength. Supplying a high protein diet after a period of weight loss increased wool growth. This changed the position of break along the staple and increased the fibre diameter at the point of break from 13.0 to 13.9 J.1m without affecting staple strength. It also increased fibre diameter and mean fibre length growth rate. The low staple strength group had a significantly higher CV of fibre length than the high staple strength group. Fibre length growth rate to fibre diameter ratio was stable over time in the high staple strength phenotype but declined with time in the low staple strength line. The results suggest that large weight losses will reduce the difference in staple strength between animals with a history of large difference in staple strength. Rate of wool growth after the point of break did not influence this staple strength outcome.
- The opportunity exists to utilise our knowledge of major genes that influence the economically important traits in wool sheep. Genes with Mendelian inheritance have been identified for many important traits in wool sheep. Of particular importance are genes influencing pigmentation, wool quality and the keratin proteins, the latter of which are important for the morphology of the wool fibre. Gene mapping studies have identified some chromosomal regions associated with variation in wool quality and production traits. The challenge now is to build on this knowledge base in a cost-effective way to deliver molecular tools that facilitate enhanced genetic improvement programs for wool sheep.