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Genetics

Performance
ASBVs
Sheep

Goals

Improving the genetic base of the flock by buying in high quality rams has many long-term benefits. Rams can be selected using a variety of methods, including:

Performance recording
Using records to compare the performance of rams from different places can allow producers to fine-tune their ram buying decisions in the future.
Australian Sheep Breeding Values (ASBVs)
These are objective indices to provide a guide for selection of a particular trait in a ram.  Click for more information

Preparation of the ram team for joining is a critical part of the farm calendar.

Performance Recording

Traditional manual recording methods can be unreliable at producing accurate and consistent pedigree assignment. DNA verification to sire for new ram candidates creates accurate pedigree records and therefore more accurate selection and improved genetic gain.

The utilisation of DNA parentage assignment (Shepherd Ultra®)

Provides very accurate pedigree assignment using DNA information
  1. Traditional pedigree recording is not required at mating or lambing

Supports the effective use of multi-sire mating programs,
  1. more ewes pregnant to a stud ram in the first cycle and less ewes pregnant to the back-up ram
  2. aiding in identifying superior rams that have a higher servicing rate
Eliminates error prone manual recording
  • reduces labour costs and the reliance on stud lambing monitoring
  • avoids data errors from unplanned matings
Establishing a lamb’s sire and dam using Shepherd ULTRA® requires less work, less interruption and increases pedigree accuracy.

Australian Sheep Breeding Values (ASBV's)

Australian Sheep Breeding Values (ASBVs) are an estimate of an animal’s true breeding value based on pedigree and performance recorded information. They are essentially a projection of how that animals progeny will perform for a range of traits.

To make selection decisions easier key traits are combined into a selection index which provides focus to a breeding program aligned to give objective i.e. maximising profit or increased emphasis on increased growth and eye muscle area.

By selecting Rams based on their ASBVs farmers can improve the genetic merit of their flock for a range of profit driving traits including;

Birth Weight
  • ASBV is based on measured birth weight of lambs adjusted for age of dam. Where birth weights are not available it is estimated as a correlated trait from weight measurements taken as the lamb matures. The lower the ASBV the lighter is the estimated progeny birth weight potential.
Weight
  • ASBVs describe the animals’ genetic merit for growth rate. A positive ASBV means the animal is genetically faster growing. Weight ASBVs are available for weaning (100 days), post-weaning (200 days), and yearling, hogget and adult ages
Fat Depth
  • ASBVs describe the value of an animal’s genes for fat depth at a constant weight – a negative ASBV means a genetically leaner animal.
Eye Muscle Depth
  • ASBVs describe the value of animals’ genes for eye muscle depth at a constant weight – a positive ASBV means a genetically thicker-muscled animal, and one that will have slightly more of its lean tissue in the higher-priced cuts.
Wool Weight
  • ASBVs describe the value of animals’ genes for wool weight – a positive ASBV means a genetically heavier-cutting animal.
Fibre Diameter
  • ASBVs describe the value of an animals’ genes for finer or coarser wool – a negative ASBV means a genetically finer animal. In addition fibre quality measurements such as staple length, staple strength, CV and curvature can be converted into ASBVs
Reproductive ASBVs
  • describe the value of animals’ genes for lambing and/or marking rate.
Worm Egg Count (WEC)
  • ASBVs describe the value of animals' genes for carrying worm burdens - a combination of being genetically less likely to pick up worms and being better at getting rid of them.

Further Reading

A Better Way To Buy