Why is BLUP fundamental to modern Merino breeding? Prof. Gert Erasmus explains how BLUP breeding values enable animals to be compared across different environments, using performance records, pedigree relationships and genetic links between contemporary groups. He outlines the management requirements for reliable evaluations and discusses the opportunities for Merino breeders to improve selection accuracy and progress towards national and international genetic evaluation.
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BLUP and the MERINO breeder Prof. Gert Erasmus - Albertinia Merino breeders tried to circumvent this problem with, inter alia control flock tests, group breeding schemes, progeny tests and veld ram clubs. The problem was completely solved just more than twenty years ago with the introduction of BLUP. If BLUP is carried out correctly and there are strict scientifically based rules and regulations, it can be a very accurate (best) method of comparing animals over different environments. Not only production and reproduction performance, but also visual assessment, using the method of linear type scoring can be included. It is, in all aspects, what Prof. De Lange refers to as “precision breeding”.
Some managerial aspects need to be highlighted to afford this “precision breeding”. Firstly, parentage must be recorded. BLUP utilises all genetic relationships among animals to predict breeding values. Interesting to note is that no data are ever discarded, since more data, even from dead animals, increase accuracy. It stands to reason that there should also be genetic ties among contemporary groups, meaning that some animals should have progeny in different contemporary groups. If there are no genetic links, groups cannot be compared. Secondly ALL animals (even culls) should be measured and scored. BLUP needs all available information to increase accuracy Thirdly, measurements should be taken at the best age determined by research and all prior managerial practices, like e.g non-shearing, adhered to. “Precision breeding” requires precision inputs. BLUP is the Best Linear Unbiased prediction of an animal’s breeding value – in other words how it will breed relative to all animals in an analysis. This analysis ideally involves
Performance testing on its own has serious limitations in the genetic improvement of livestock. Animals can, for instance, only be compared within a contemportary group where all non-genetic factors, such as climate, sex, management and age are identical. the entire breed in a country, or even in the world. Apart from being extremely accurate, BLUP obviously affords another major advantage in that the “effective population size” is vastly increased. A breeder can then select the best animals he can afford to satisfy his needs from the entire breed. Dr Jan Hofmeyr put it so aptly: “There is an effectiveness in numbers in animal breeding operations, which is seldom equalled by breeding skill”. For breeders willing to go the whole hog, there is also the wonderful prize of a global market. Our …
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