EBVs

Estimated Breeding Values (EBVs) are predictions of an animal’s genetic merit, based on the 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.

EBVs are expressed in the units of measurement for each particular trait. They are shown as positive (+) or negative (-) differences from the breed base. For example, a bull with an EBV of +50kg for 600 day weight is estimated to have genetic merit 50kg above the breed base of 0kg. Since the breed base is set to an historical benchmark, the average EBVs of animals in each year drop has changed over time as a result of genetic progress within the breed.

The absolute value of any EBV is not critical, but rather the differences in EBVs between animals. Particular animals should be viewed as being “above or below breed average” for a particular trait only if their EBVs are higher or lower than the average EBVs of all animals born in that year. The most 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, milk ability, growth, carcase merit and docility. When using EBVs to assist in selection decisions it is important to achieve a balance between 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.

EBVs are provided for the following traits:-

     Gestation Length                 Birth Weight                          Milk Ability
     Calving Ease (direct)           Calving Ease (daughters)      Days To Calving
     200 Day Weight                   400 Day Weight                     600 Day Weight
     Mature Cow Weight            Carcase Weight                     Eye Muscle Area
     Scrotal Size                           Rump Fat                               Rib Fat
     Retail Beef Yield %             Docility                                  Intra-muscular Fat % (marbling)
 

Breed Average EBVs for 2003 Born Calves