A Selection Index is effectively a single unit value predicting a breeding animal’s profitability for a defined commercial production system and market end-point. They are based on weightings on specific EBV traits deemed important for that production system. Ranking animals on their Selection Index value sorts them based on their progeny’s expected profitabil- ity for the targeted production system.
As a guide to using Selection Indexes, it is recommended that producers, both seedstock and commercial, undertake the following steps:
- Identify the Selection Index of most relevance
- Rank animals on the Selection Index
- Consider the individual EBVs of importance
- Consider other traits of importance that may not be accounted for in the Selection Index (e.g. temperament, structural soundness)
Before using Selection Indexes, producers should identify the index that is of most relevance to their particular production system. Following are the descriptions for the 3 Shorthorn Selection Indexes:
- Domestic Maternal Index (DOM) – Estimates the genetic differences between animals in net profitability per cow joined in a self replacing commercial herd in a temperate environment targeting pasture grown and finished steers for the domestic trade (eg. supermarket). Steers are marketed at 480 kg live weight (260 kg HSCW and 10 mm P8 fat depth) at 22 months of age.
- Export Maternal Index (EXP) – Estimates the genetic dif- ferences between animals in net profitability per cow joined in a self replacing commercial herd in a temperate environ- ment targeting steers for the Japanese B3 market. Steers are pasture grown to feedlot entry then feedlot finished for 150 days. Steers are marketed to the feedlot at 450 kg live weight, and then slaughtered after finishing at 675 kg live weight (370kg HSCW).
- Northern Maternal Index (NM) – Estimates the genetic differences between animals in net profitability per cow joined in a self replacing commercial herd in northern Aus- tralia targeting the export trade. Steers are finished on grass and marketed at 600 kg live weight (320 kg HSCW and 10 mm P8fat depth) at 28 months of age.
For more information contact the Shorthorn SBTS Technical Officer, phone: 02 6773 2472.
“Yamburgan cattle are cattle that com- bine performance and docility and are sought after by both lot feeders and grass finishers who consistently comment on the high percentage of the cattle that meet the highest specifications.”
