What's Performance Recording all About?
Estimated Breeding Values (EBVs) are predictions of an animal's genetic merit, based on available performance data on the individual and its relatives.
In the calculation of EBVs the performance of individual animals within a contemporary group is directly compared to the average of other animals in that group. A contemporary group consists of animals of the same sex and age class within a herd, run under the same management conditions and treated equally. Indirect comparisons are made between animals reared in different contemporary groups, through the use of pedigree links between the groups.
With the widespread use of artificial breeding and trading of genetics among seed stock herds an extensive network of pedigree links has been established throughout the Angus breed. These pedigree links enable the adjustment for environmental differences between herds, years and management groups. This allows comparisons between animals from totally different environments and management conditions.
EBVs are expressed in the units of measurement for each particular trait. They are shown as +ive or -ive differences from the breed base. For example, a bull with an EBV of +50 kg for 600-Day Wt is estimated to have genetic merit 50 kg above the breed base of 0 kg. Since the breed base is set to a historical benchmark, the average EBVs of animals in each year drop has changed over time as a result of genetic progress within the breed.
While EBVs provide the best basis for the comparison of the genetic merit of animals reared in different environments and management conditions, they can only be used to compare animals within the same breed. The EBVs for different breeds have different bases and are subject to different rates of change over time. Consequently, Angus GROUP BREEDPLAN EBVs cannot be validly compared with EBVs of any other breed.
The absolute value if any EBV is not critical, but rather the differences in EBVs between animals. Particular animals should be viewed as being above breed average for a particular trait only if their EBVs are better than the average EBVs of all animals born in their year drop. A useful "benchmark" is the average EBVs for calves born in their year drop.
EBVs are published for a range of traits covering fertility, calving ease, maternal performance, growth and carcase merit. When using EBVs to assist in selection decisions it is important to achieve a balance between the different groups of traits and to place emphasis on those traits that are important to your herd, your markets, and your environment. One of the advantages of having a comprehensive range of EBVs is that you can avoid extremes in particular traits and select for animals with balanced overall performance