Reliability or Rel is the measure of accuracy or degree of confidence in the genetic index for a particular animal. Reliability is important when assessing an index (EBI or Eurostar) so that you can identify just how accurate this animals index is. For example when selecting an AI sire for breeding, a sire who has a lot of data backing up his index is more ‘reliable’ (>90%) and the amount that the sire’s figures are likely to fluctuate in the future is reduced. On the other hand take another AI sire who has less data backing up his index and is less ‘reliable’ (<30%), this sire’s figures are more likely to fluctuate in the future as all of his progeny performance data has yet to come in.
What is reliability %?
Different animals will fall into different reliability ranges depending on the levels of data available for that animal (own performance, ancestry and progeny). The table below gives an explanation of which animals are likely to fall into each reliability % range.
What is a Genetic Index?
A Genetic Index is the end result of a series of routine steps known as a ‘Genetic Evaluation Run’. For example, for a Stockbull, a genetic evaluation run will identify all of the calves of a Bull and compare their performance records to those of the other animals reared alongside them in the same herd. Any Genomic (DNA) data together with records from relatives of the bull is also included. Some traits have more of an impact than others on the resulting index, simply because they are more valuable e.g. ‘Kgs protein’ is a more valuable trait than ‘carcass confirmation’ for a dairy cow.
The Genetic Index is expressed in €uro’s as the goal of this process is to estimate how profitable an animal is for breeding. When mated, unless the calf is genomicly tested a Bull or cow will only ever transmit half of their euro value to the resulting calf. This is called a parental average or PA.
Example: A Bull with an EBI of €300, if mated to a cow with an EBI of €200, is expected to sire a daughter with an ‘EBI’ of €250 (€300+€200 / 2 = €250). This means that she will be €250 more profitable than the base average Irish cow. This calves index may then change over time depending on what data comes in related to this animal for example; performance data, genomic data, progeny data etc.
Reference Material: https://issuu.com/herdplus/docs/___uro-stars_explained