Catalogue - Welshpool Livestock Sales

9Longevity (years)Calving Interval (days)Docility (%)Scrotal Circumference(cm)Genetic potential for long life in thebreeding herdGenetic potential for the time takento get back in calfGenetic potential for being calmwhen handledGenetic potential for scrotal size.Linked to male serving capacity andpuberty of daughters.High positive values for animalslikely to remain in the herd for longerHigh negative values to breedcows that get back in calf quicklyHigh positive values for animalsthat are likely to be more calm whenhandledHigh positive values for animalswith higher likely serving capacityand earlier maturing daughters.2. HOW ARE EBVs CALCULATED?EBVs are calculated using information from several sources:Measurements from the animal itselfMeasurements from the animal’s herd mates (known as ‘contemporaries’ *)Measurements from the animal’s relatives and their contemporariesThe degree to which one trait influences another (known as a ‘correlation’ * )The degree to which each trait is passed on to the next generation (known as ‘heritability’ *)* Terms explained belowPerformance RecordsPedigree Info.Trait HeritabilitiesTrait CorrelationsEach EBV calculation involves solving a set of simultaneousequations where the ‘unknowns’ are the genetic value of the animaland the environmental effect on its performance. When carried outmany times, using all the information on the animal above, theequations are able to quantify the unknown genetic component.The end result is the EBV and over time, as more pedigree andperformance data is added, the solution to the equations becomesmore accurate as the true breeding value of the animal isapproached.EBVsINDEXESHeritability and CorrelationsHeritabilityThis is a term used to describe the strength with which traits are inherited and it varies depending on the trait inquestion. Generally:Traits associated with reproduction and survival have low heritabilitiesMilk production and early body size have medium heritabilities