More detailed information regarding each selection index is provided in the downloadable document.

The Tropical Composite BREEDPLAN analysis currently reports four different selection indexes. These are the:

• Self Replacing Selection Index
• Terminal Selection Index

All of the selection indexes described above have been derived using BreedObject software. The BreedObject selection index development process involves four major steps. These steps are:

1. A detailed description of the input costs and value generation of the commercial herd and target production system.
2. Once the target production system is described, the BreedObject software evaluates how each trait influences profitability and the economic value of improving each trait.
3. The BreedObject software then assesses what emphasis needs to be applied to each Estimated Breeding Value (EBV) trait to achieve the maximum profitability in the production system and for the market end point for which that index was designed. This step includes evaluating the selection response expected from direct selection on the individual EBVs and the correlated responses expected from selection on related EBVs.
4. The importance placed on each EBV results in the selection index value that is calculated for each animal.

Each selection index describes a different production system/market scenario and relates to a typical commercial herd using Simmental bulls. As is the case for EBVs, each selection index can be used to rank and compare animals on their genetic merit. Producers are advised to use the selection index that most closely aligns to their production system. See the Using Tropical Composite BREEDPLAN Selection Indexes tip sheet, available in the Help Centre on the BREEDPLAN website, for further information on the identification and utilisation of the most applicable selection index for your herd.

All selection indexes are reported in units of net profitability per cow mated ($) for the production system/market scenario they describe. Selection indexes account for both sides of the profit equation (costs as well as income), and also reflect the relative short and long term profit associated with possible selection decisions. For example, short term profit can be generated by a bull through the sale of his progeny, and the longer term profit generated by his daughters in a self-replacing cow herd.

Each of the selection indexes are focused on efficient beef production while also targeting the following specifications:

Self-Replacing Selection Index - Estimates the genetic differences between animals in net profitability per cow joined for a typical self-replacing commercial herd. Selected heifers are retained for breeding and so maternal traits are of importance. Steers and surplus heifers are pasture grown and target finishing at 28 months of age. Steers target 600 kg live weight (330 kg carcase weight and 10 mm fat depth). In response to industry feedback, positive emphasis has been placed on carcase quality traits.

Terminal Selection Index - Estimates the genetic differences between animals in net profitability per cow joined for a typical commercial herd using Tropical Composite bulls over Bos indicus cows. All progeny are pasture grown and target finishing at 28 months of age. Steers target 600 kg live weight (330 kg carcase weight and 10 mm fat depth) and heifers 555 kg (295 kg carcase weight and 12 mm fat depth), at 20 months of age. In response to industry feedback, positive emphasis has been placed on carcase quality traits.

More detailed information regarding each selection index is provided on the following pages.

If you have any further queries regarding the Tropical Composite BREEDPLAN Selection Indexes, please do not hesitate to contact staff at your BREEDPLAN processing centre.