Selection indexes assist beef producers to make selection decisions that take into account the relevant growth, carcase, fertility and efficiency attributes of each animal to identify candidates whose progeny will be the most profitable for a particular commercial enterprise. Selection indexes provide an overall indication of an animal’s genetic value for profit in a specific production system/target market and are calculated based on weightings placed on individual traits that are deemed to be important for that production system.

The weightings are calculated using BreedObject software that analyses all sources of costs and income for the production system represented by each selection index. As such, selection indexes account for both sides of the profit equation and reflect the short and long term profit possible through selection of superior genetics. 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.

Best Practice Guide to Animal Selection Using Southern African Brahman Selection Indexes

Incorporating selection index information into breeding decisions takes the hard work out of trying to decide how much emphasis you need to put on individual EBVs when determining which animals you want to retain in your herd or purchase. The recommended strategy for selecting animals is to complete the following steps:

1. Identify the selection index of most relevance to your or your client’s breeding objectives. This decision should be aided by the index descriptions at the end of this document.
2. Rank animals on the chosen selection index. This can be done via the web search facility available for the breed.
3. Consider the individual BREEDPLAN EBVs of importance. All breed level selection indexes are designed for the average of the production system specified in their description. This means that individual farm environments and management choices may require that their own thresholds are applied. For example, if looking for a bull to use over heifers, particular attention should be paid to Calving Ease and Birth Weight EBVs.
4. Consider other traits of importance. Structure, fertility, temperament, genetic conditions and pedigree are all important additional considerations.

Further information is available in the A BREEDPLAN Guide to Animal Selection tip sheet that can be found in the Help Centre on the BREEDPLAN website.

Available Southern African Brahman Selection Indexes

Three selection indexes are currently reported for the Brahman Cattle Breeders Society of Namibia, the Brahman Cattle Breeders’ Society of South Africa and Brahman breeders recording with the Zimbabwe Herd Book. These are the:

• Rangeland Grazing Index
• Wean Index
• Feedlot Index

Each selection index is reported in units of net profitability per cow mated (R), and targets the following specifications:

Rangeland Grazing Index

• Commercial self-replacing herd targeting the export market.
• Heifers are retained so maternal traits are important.
• Steers target 500 kg live weight (250 kg HSCW) at 30 months of age.
• This index is also suited to using Brahman sires over mixed breed cows.

Wean Index

• Commercial self-replacing herd targeting the sale of weaners.
• Acknowledges that progeny will be grown on for slaughter at later ages.
  • Can be used in conjunction with either the Rangeland Grazing or Feedlot selection indexes to account for traits expressed after weaning.
• Heifers are retained so maternal traits are important (strongest emphasis of the 3 indexes).

Feedlot Index

• Commercial self-replacing herd targeting the sale of yearlings.
• Heifers are retained so maternal traits are important.
• Steers finished in feedlot (120 days).
• Steers target 400 kg live weight (230 kg HSCW).
• This index is also suited to using Brahman sires over mixed breed cows.

More detail on the trait and EBV emphasis for each of the selection indexes described above is available in the Southern African Brahman Selection Indexes: Technical Specifications tip sheet that can be found in the Help Centre on the BREEDPLAN website.

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