Data quality

The quality of the breeding values you receive depends on the quality of the data.

Pedigree

Pedigree (sire and/or dam) is integral to Australian Sheep Breeding Values (ASBVs). The breeding values are estimated using relationships between animals. So, if the sire of an animal is known but not the dam, half the genetics of the lamb are missing.

Information on other relatives such as siblings and grandparents are also used in the calculation of breeding values if this information is provided.

RAMping Up Genetic Gain reports

Sheep Genetics clients can access a RAMping Up Genetic Gain (RUGG) report. These reports give feedback about how to improve your breeding program design and data quality.

You can download this report from the Your Flocks tile on the search page when logged in.

Linkage

Linkage compares genetic performance across flocks and environments by using common genetics between flocks, such as using a sire from another flock that has progeny elsewhere.

When progeny from one sire is managed in two different flocks that sire can be benchmarked to the performance of other sires used in each of those flocks.

Linkage is calculated for each trait group. For example, to be linked for fleece weight, it is important to use a sire that has progeny recorded elsewhere for fleece weight, and record his progeny for the same trait on-farm. Calculate linkage based on the animals used over the last five years.

Linkage between flocks, years and management group is vital to have a fair comparison of genetic performance. Therefore, it’s important to continuously share genetics with other flocks to stay linked.

Management groups

Management groups account for differences in environment, such as feeding or treatment. A management group number accompanies every animal record. This number describes which animals have been running together prior to a measurement being taken.

This information is key because only the physical performance of animals running together (have the same environment) are compared.

To guarantee the management group information is accurate, please ensure:

Management groups are clearly identified for animals that have run together prior to the measurement being recorded
Management groups are genetically linked within and across years (using a common sire/s between groups)
The number of effective progeny in the group is maximised
Animals that have different treatment after a base trait has been recorded are clearly identified in a separate subgroup for following trait measurements (eg. show sheep)
Animals managed in the same group have their performance measurements recorded on the same date.

Fixed effects

Fixed effects refer to known differences between animals that are not genetic and include:

Age of the animal – do you know the date each animal was born?
Age of the dam – what is the impact of having a maiden dam compared to an adult?
Birth type – was the lamb born a single or twin?
Rear type – was the lamb raised as a single or twin?

Record this information to estimate accurate Australian Sheep Breeding Values (ASBVs). If these are not included in the analysis, the breeding values will be biased.

For example, imagine an animal that is born as a single lamb on the first day of lambing. At weaning, it will be much bigger than a lamb born in a litter of two on the last day of lambing.

If age and how the lamb was raised are not accounted for, it could be assumed the first lamb has better genes for growing faster than the second lamb that may not be the case.