EBVs

Estimated Breeding Values (EBVs) are predictions of an individual’s genetic merit for a specified trait. Calculated for livestock and other animals, they express how much an animal is expected to contribute genetically to its offspring, relative to the population mean. EBVs are derived from performance data, pedigree information, and, increasingly, genomic data, using quantitative genetics methods such as Best Linear Unbiased Prediction (BLUP) or single-step BLUP.

A positive EBV for a trait indicates above-average genetic merit, while a negative EBV indicates below-average merit. EBVs are expressed in the units of the trait (for example, kilograms of milk yield or pounds of carcass weight) and are used in selection indexes and mating plans to improve genetic gain over generations. The accuracy of an EBV, a value between 0 and 1, reflects the reliability of the prediction and tends to increase with more data and better information.

Transmitting ability and PTA: The value that a parent passes to its offspring is known as the transmitting ability (TA) or PTA (predicted transmitting ability), and is closely related to the parent’s EBV. In practice, breeders use EBVs and PTAs when ranking animals for breeding decisions, particularly when selecting sires and dams.

Genomics: Genomic EBVs (GEBVs) integrate DNA marker information and can increase accuracy, especially for young animals. Modern methods include single-step approaches that combine pedigree, phenotype, and genotype data.

Limitations: EBVs are population-specific and depend on the quality and scope of available data. They may not extrapolate well to different populations or management systems, and regular updates are needed as new data accumulate.