Terminal Sire Index

(Charolais; Suffolk; Texel)

The Terminal Sire Index has been successfully used in the UK for over 15 years. Its use has greatly enhanced the growth potential and carcase attributes of all the main terminal sire breeds, producing a population of recorded rams whose progeny are more valuable to the commercial producer.

Breeding Objective

To increase the yield of lean meat in the carcase whilst minimising any associated rise in carcase fatness.

Influential EBVs

Scan weight

Muscle depth

Fat depth

Carcase lean weight (CT scanning breeds)

Carcase fat weight (CT scanning breeds)

Recent Developments

In 2004 the Terminal Sire index was modified for certain breeds, to more closely

meet their individual breeding objectives. These enhancements included:

• A change to the weighting of fat depth, placing an additional penalty on the

index of rams with low fat depth EBVs whose progeny were perceived to be

more difficult to finish under extensive conditions.

• A positive weighting was applied to muscularity, for those breeds involved in CT

scanning, in order to enhance carcase shape.

• The provision of an economic index. This enables the breeding potential of

recorded stock to be expressed in financial terms.