Accuracy: In relation to relationship and heritability
Recording from controlled and uniform environmental conditions
Heritability Size Examples
height Larger than 45 %, Fat deposition, fat % in milk
Low Smaller than 10 %, Reproduction traits
Notes:
Furthermore, the accuracy of a breeding value estimate also depends on how closely related the individual is with the animals which have records.
In chapter 12 we discuss how the quality of the data can be improved by using different breeding measures. By using artificial insemination the data gets a better genetic structure. Often the term “connectedness” is used when describing how well the data is spread across the herds.
The technical accuracy can be improved, if the recordings are done under well controlled and uniform environmental conditions, as it is the case in breeding research stations. This will be further discussed in chapter 12.
By investigating the formula for accuracy the following is derived:
1) When dealing with high heritability the individual’s own record is a good source of information.
2) When dealing with low heritability many records can compensate for low accuracy in a single record. Many records are only available by using large groups of offspring, where the animals occur either as offspring or as full- or half sib.
High heritability in a trait is always more than 45 %, as for instance back-fat or fat percent in milk. The heritabiliy is low when it is below 10%, as for instance reproduction traits and disease resistance. Middle-size heritability is from 15-40 %, as for instance growth traits.