Phenotypic expression of type traits changes over span life and may be regulated by different set of genes ; if this were the case type traits genetic evaluation should consider the age when different observations in the same animal are recorded. Milk production in south of Chile is mainly based on grazing, therefore concern exists because Holstein genetic introduced in the country may not fit local grazing conditions. Taller cows raised and performance tested in especially designed dairy barns may not have the required walking ability to produce on grazing conditions. Soil compaction produced for heavier cows is also an issue to be considered. Dairy cattle in Chile are not genetically evaluated for type traits, breeding stock genetic merit is erroneously extrapolated from foreign dairy sire catalogues available from frozen semen companies. Genetic evaluation of conformation traits like stature, that changes with age, requires that cows be measured several times across their life, therefore a method that account for changes as an animal becomes older should be used to obtain closer estimation of the animal’s breeding value
Proceedings of the World Congress on Genetics Applied to Livestock Production, Volume 2002. Session 1, , 1.63, 2002
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