Enhancements to the BreedObject Selection Index Software

Brad Walmsley

Like breeding values (EBVs), selection index technology is a well-established, science-based methodology that is used in many livestock species around the world.

The selection indexes calculated within the TransTasman Angus Cattle Evaluation are generated using a software package called BreedObject. The same software is utilised in the genetic evaluations conducted for many other beef breeds across Australia, New Zealand, the United Kingdom, South America and South Africa. Selection indexes generated by BreedObject are as equally concerned with production costs as they are with market returns. Thus, they reflect both sides of the profit equation for a beef production system.

Recent Developments in the BreedObject Software

Like the science behind EBVs, research into improving the methodology behind selection indexes is ongoing and recently a new version of the BreedObject software has been made available to industry. This new version of software has been utilised in the research selection indexes that have been released by Angus Australia. New developments in this version of the BreedObject software include: · Improved modelling of young animal growth.

This includes: · Separate modelling for each sex rather than assuming there is a fixed difference between them. This gives the potential for each sex to have different market end points. · Revised modelling of growth during backgrounding and in the feedlot. · Revised modelling of feed requirements including net feed intake (breeding objective) for young animals and the impacts on production costs. · Improved modelling of cow weight and condition score throughout the year. This includes: · More advanced modelling of cow weight, and subsequently feed requirements, at times of the year when feed is in short supply and/or expensive. · Inclusion of cow condition score and production penalties for cows outside of optimum condition (too lean or too fat). · Revised methodology for valuing cows when culled. This allows for variation in sale weight and value between cows culled for various reasons (e.g. cast for age, reproductive failure, poor condition, etc.).

· Enhanced modelling of carcase market specifications and values. · This includes the ability to handle non-linear price structures like carcase grids that penalise both too lean and too fat carcases, and/or those that penalise under- and overweight carcases. These developments have changed how EBVs are valued in selection indexes. In particular, the enhanced modelling of cow weight increases the impact that total cow feed costs (i.e. length of feeding + feed price + feed quality) have on the profitability of the represented commercial production systems. For example, recent research showed that altering the cost and/or length of time of supplementary feeding has a larger effect on the selection indexes produced in the new BreedObject software than in past versions. This result demonstrates that the new software can construct selection indexes that can be tailored to the different production environments found across Australia where variation in cow feed costs exist. The new BreedObject software also contains developments to allow for the future inclusion of new traits in the selection indexes. These components are not yet available for implementation but give an indication of some of the data which may be valuable for breeders to collect for the future. The data includes: · Methane (carbon) valuing (where desired). · The incidence of and possible penalties within the herd (e.g. loss of production, lower sale value) for animals with undesirable: · Leg structure. · Docility. · Udder conformation.

Where to find more information on BreedObject and Selection Indexes

More detail on BreedObject can be found at http://www. breedobject.com/page/About_BreedObject.html . Acknowledgement: This article is a modified version of an article that first appeared in Summer 2018 SBTS & TBTS Update Magazine and was written by SBTS staff and Dr Bradley Walmsley from the Animal Breeding and Genetics Unit (AGBU).