Measuring traits
Meat & Livestock Australia September 22, 2021
To get the most out of the genetic evaluation, it is recommended to measure the traits you and your clients are interested in as directly as possible. You can measure as many or as few traits as you would like – there are no rules for which traits you must measure. However, there are some requirements around how the data is collected for some traits, which are outlined below. For more information on trait measuring, please refer to the Breeder’s Guide. A full list of traits is also available on the Sheep Genetics website.
Below are some requirements surrounding the different trait measurements.
Fleece traits
- A minimum of six months wool growth is required to measure fleece weights.
- A minimum of five months wool growth is required for fleece tests (eg fibre diameter, staple length).
- Fleece measurements can be recorded on animals aged between seven months and six years of age.
- It is recommended to include the belly when recording fleece weight (if you do not include the belly, make sure you do not include them for all animals).
- Weigh the complete fleece before skirting.
- If you don’t record accurate dates of birth, tip shearing the animals can help to account for the unknown age difference.
Weight traits
- Birth weight needs to be measured within 24 hours of birth.
- Birth weight can be measured on live lambs or where carcases are whole.
- For later weight measurements (weaning onwards) it is recommended to curfew animals for at least four hours prior to weighing, ensuring that animals have emptied out to minimise any impact of gut fill on the measurement.
- Record adult weights within the 30 days prior to joining so adult weight records are not affected by reproduction.
Carcase traits
- Ensure a Sheep Genetics accredited scanner measures fat and muscle depth. A list of accredited scanners is available on the Sheep Genetics website.
- Measure body weight the same day animals are scanned.
- Scan animals at a similar age to when your commercial clients market lambs.
- The group must have an average body weight of at least 30kg.
- The group should have an average of at least 1.5mm of fat. This helps to ensure there is variation in trait expression.
Worm egg count
- The average count for the group must be over 300 eggs per gram when individual samples are taken.
- Use bulk sampling to get a gauge of the expression of worm burden in the group before individually sampling. This helps to ensure the group average is over 300epg when you get to individually sampling.
- If measuring worm egg count (WEC) at weaning age, sample lambs at least six weeks after weaning to ensure the count reflects the lamb’s immunity and not transferred immunity from the dam.
- If you have Haemonchus (Barber’s Pole) then the average count should be 500–1,000 eggs per gram (epg). This is because this type of worm lays more eggs.
Reproduction traits
- It is crucial to record reproduction information on dry ewes and ewes that lambed and lost.
- At least 70% of the lambs in a drop must have dam pedigree.
- Include the joining information including ram ID, joining dates, conception method and group, as well as any backup joining events.
- You must include any chemical hormone interventions (such as CIDRs) if you have used them.
- Reproduction can be a complex trait to record, with information being captured from joining through to lambing and to weaning. A detailed recording checklist is available on the Sheep Genetics website.
Visual traits
- Use the Visual Scores Guide to record visual traits. This can be found on the Sheep Genetics website.