Select the most profitable breed or crossbreeding system to achieve genetic progress
Guidelines for selecting the breeding system
Consider selection of the best genotype for your enterprise as part of setting the enterprise direction (refer to Procedure 1 of Module 1: Setting directions).
Assess merits of a change in breed or crossbreeding compared to within-breed selection only
Evaluate the merits of changing breeds, crossbreeding or within-breed selection alone. In general, the genetic variation within breeds is large and will allow many breeds to compete in a range of markets. So the decision about whether to move to an alternative breed or cross will be based on an assessment of whether the size of the changes needed in the traits of your current herd is so great that it will take too long to achieve by simply selecting better bulls within your existing breed or source of bulls. It is important to calculate the costs, time and effort required to implement a new breeding system to ensure that the advantages outweigh the difficulties.
Economic values calculated in Procedure 1 can help identify the most beneficial traits for improvement. But changing breeds may cause large changes in some traits, and may change the relativity between traits, such that a decision to change breeds will require an iteration of Procedure 1 to calculate a new index.
Options to change herd genetics
- Replace the existing herd by buying in an alternative breed. This is the quickest method, but also the most costly. Embryo transfer is also an option, although this may too expensive for most commercial operations.
- Build up to the desired breed or combination by crossing with bulls from the chosen breeds. This option is slower, but is generally less costly and brings with it the complementary hybrid vigour that comes from crossing genotypes during the transition to the new breed or breed combination.
- Decide what the ongoing breeding program will be: a designed crossbreeding program or a straight breeding program using the new breed.
Although ongoing advantages can be achieved by implementing a planned crossbreeding program, some of the potential disadvantages include:
- additional herd management associated with crossbreeding
- potential discounting of crossbred animals, particularly for some breeds when sold through the saleyard system or to specialised markets that specify breed composition
- time and cost required to bring the herd into ‘equilibrium’
- suitability of crossbreeding to larger herds that have more bulls and larger lines of sale animals.
Sources of information for breed and crossbreed averages for important traits are presented in Tool 4.2and Tool 4.3. Tool 4.2 provides information about multibreed EBVs that allow valid comparisons of bulls across a selection of breeds for a range of traits. The comparison is limited by the lack of data required for head-to-head comparisons of breeds, and is currently restricted to the Angus, Hereford, Limousin and Simmental breeds. Unfortunately, little extra data has been generated and no new multibreed comparisons have been published.
After deciding on breed and whether to crossbreed, further genetic progress relies on selection of replacement bulls within the available genotypes (see Procedure 3).
What to measure and when
Consider a change in genotype when:
- potential genetic improvement (for economically important traits) within breed isn’t adequate to make the required changes for your program
- potential for marginal return on investment for an alternative breed is greater than for other investment options
- cash flow during the transition period to the new breed or cross is maintained at acceptable levels.
This is a strategic decision. The measures that are needed for an economic evaluation of options are described in Module 1: Setting directions.