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LPI reliability included on the proof sheet

Reliability indicates the level of confidence with respect to the published LPI index by CDN. The higher the reliability, the closer we are to the true LPI value of the bull.


LPI interpretation based on reliability: what does the graph tell us?

This graph shows how differences in reliability for Holstein sires can be interpreted at various periods of their life. It has been produced with official data from CDN. Thus, as reliability increases, the closer we get to the sire’s true and precise LPI value, which is usually known when the sire reaches over 5,000 daughters in its proof. It must be noted that values illustrated in the graph prove to be true in 9 cases out of 10. At birth, a sire’s LPI is calculated based on the parent’s average. The 2800 point LPI value is reliable at 35% and it could vary by ± 530 points. At the other end of the graph, a sire for which the performances of thousands of 2nd generation daughters would have been evaluated, would indicate a 99% reliability of its 2800 points LPI value (± 66 points).

This graph puts into perspective that even if genomics enhances the reliability of values (by 35 % to 70 %), the variation gap is only reduced from ± 530 to ± 360 points. As with a sire with a 2800 point GPA value and obtains a progeny proof with 90% reliability, the estimated reduction in the gap is thus reduced substantially, from ± 360 to ± 108 points.


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