Breeding Indexes in Cattle
What is a Breeding Index?
While EBVs aid the selection of breeding stock according to specific traits they can also be combined into selection indexes to meet wider breeding objectives.
An index is an overall score of genetic merit combining the relative economic values of several EBV traits.
Signet offers five selection indexes:
Beef value: The economic value of an animal in terms of the financial merit of its offsprings’ carcases
Calving value: The economic value of an animal in terms of gestation length and difficult calvings
Maternal value: The economic value of an animal’s genetic ability to produce breeding females
Maintenance value: The economic cost associated with mature size
Maternal production value: The economic value of an animal in terms of its genetic potential to produce females for breeding and animals with beef carcase characteristics, calculated from the four sub-indexes listed above.
The EBVs accounted-for in the calculation of these indexes is shown below:
Indexes cannot be compared between breeds. To avoid confusion, Index values are sometimes prefixed with two letters which indicate which breeder they refer to, e.g. LU for Luing
When using a Breeding Index it is important that your breeding objective is broadly similar to that of the Index in question, otherwise you may unwittingly change aspects of your herd that you did not necessarily want to.