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During the last several years, beef cattle breed associations have been accumulating hundreds of thousands of animal records that have been sent to them by breeders. This vast amount of information, coupled with new computer and statistical technology, has enabled breed associations to produce performance pedigrees. Performance pedigrees bring traditional ancestral pedigrees to life by presenting meaningful data in a logical format. The information in performance pedigrees may be used by both commercial and seed stock producers for bull and female selection.
Performance pedigrees are meaningful because of a concept known as estimated breeding value (EBV). This fact sheet discusses the EBV concept and should help you understand performance pedigrees.
Breeding Value
EBVs are not mysterious. If you accept and understand the following basic genetic principles, then you can understand EBVs.
•	Genes have their effects in pairs;
•	An animal transmits a sample one-half of its genes to its progeny; and
•	Only a portion of the variation measured in a trait is due to genes (this portion is termed heritability).
An EBV for an individual is determined by the heritability of the trait and production records from the individual and his/her relatives, weighted according to the genetic relationship between the individual and the relatives.
Because EBV is an estimate of breeding value, it needs to be defined. To understand where breeding value fits into the total scheme, see figure 1.
Phenotype (how the animal looks—its size, color, etc.) is determined by the animal’s genotype and the
environment in which it was raised. Each trait that can be measured or observed is a phenotype. For example, if a bull has an adjusted 365-day weight of
1.125	lb., his phenotype for yearling weight is
1.125	lb. Every animal has nearly an unlimited number of phenotypes, with each phenotype having a different genotype.
Environmental factors affecting phenotype may be divided further into known and unknown effects. We can make adjustments for known factors such as age of dam in calculating an adjusted 205-day weight. Adjusting for age of dam minimizes the environmental (nongenetic) effect that age of dam has on weaning weight and improves the accuracy of selection. Unknown effects, such as injury or sickness, are difficult to adjust for, but they can be minimized by managing cattle in contemporary groups (groups of cattle managed together—same age, pasture, lot, etc.)
Genotype is determined by two factors: breeding value (what genes are present), and nonadditive value (how genes are combined). The genes an animal has are determined by the genes possessed by the sire and dam, since an animal’s genes are composed of a sample one-half of the sire’s genes and one-half of the dam’s genes.
Nonadditive value is related to the hybrid vigor or heterosis effect observed from crossing unrelated
understanding Beef Performance Pedigrees
animal sciences beef