A critical element of EBV calculation is the effectiveness of performance information being submitted for the TACE evaluation.
From time to time there can be some common problems encountered in the way information is recorded or able to be used in the evaluation that may reduce the effectiveness of the data.
The reliability of performance information is influenced by many factors, with the accuracy of the measurements that have been collected often being the first things that spring to mind.
In reality however, the majority of performance quality problems are caused by the submission of performance information that is simply of limited use for genetic evaluation. Careful consideration of this information allows seedstock producers to take a large step towards ensuring that they are maximising the returns from their investment in performance recording, and in turn, the reliability of the TACE EBVs that they are obtaining for their animals.
Some common performance recording problems are:
- Herds may not record the required performance measurements at the required time or manner or will record performance information in an ad hoc manner and in a lot of situations, any performance information that is recorded is largely an afterthought of the initial management practice.
Poor Recording or Traits of Importance
- Problems may occur when seedstock producers don’t adequately record the traits of importance within either their breeding objective or the breeding objective of their clients. Although the TACE analysis may generate an EBV for traits by taking information such as the pedigree and performance on relatives this is not always the case and these may have a lower accuracy than those with their own performance recorded and analysed.
Poor Genetic Linkage
- Genetic linkage across contemporary groups both within a herd and between different herds is of fundamental importance in allowing the generation of TACE EBVs. Unfortunately, some common management practices can reduce genetic linkage significantly.
Such management practices include:
- Completely replacing all sires from one joining season to the next.
- Managing the calves from one sire differently to all other calves before recording any performance information.
- All sires used in the herd having no performance recorded progeny in any other herds (for a range of traits).
- AI calves in a herd being born at a separate time to those calves from natural matings.
Unverified Outliers or Exclusions
- While a certain degree of variation is expected within each group, when the difference between a performance record for an animal and the average of all animals in that contemporary group is greater than expected, the record for the animal is flagged as an outlier. Each time an “outlier” is identified, an outlier report is produced and included as part of the herd’s exclusions report. This report gives the breeder the opportunity to correct or verify the performance for the “outlier” animal. If Angus Australia receives no response to the outlier report, the outlier records are excluded from all future TACE analyses.
- After a DNA sample has been submitted for parent verification, genetic condition testing or a genomic profile there may also be problems with the sample not matching the registration information such as sex or pedigree as well as other quality assurance checks. Animals excluded due to a genotype issue will appear on the exclusions report.
- Outliers and exclusions appear on reports able to be downloaded by each member from the download files tab from Angus Online and should be checked frequently for actions required for each animal
Small Contemporary Groups
- Where only a small number of animals are represented in a contemporary group, there may be only a few animals to which it’s performance can be directly compared and thus the performance submitted for it cannot be used effectively by the TACE analysis.
- Small contemporary groups are a problem frequently experienced by smaller herds and without careful management, can result in considerable performance recording problems.
Selective Performance Recording
- In this situation, the performance information for an animal will only be compared with the “selection” that has been recorded. If this “selection” is not an accurate reflection of the entire contemporary group, then TACE cannot make adequate comparisons and the EBVs produced may be biased or misleading.
- The table below provides an illustration of the problems caused by selective recording (Table 1).
Inappropriate use of management groups
- The use of management groups are essential for flagging differences non genetic effects on the performance of the animal such as the environment or management. However commonly too many management groups can be allocated to a group of cattle although they have being managed together and run as one large group.
- In comparison not placing management groups against individuals or groups of cattle that have had different non genetic or environmental impacts that result in different performance outcomes can also cause significant problems in the TACE evaluation.
- If the contemporary groups are not correctly formed, the EBVs calculated will be less accurate and possibly misleading. Poor management grouping will result in TACE not being able to differentiate between calves that have had different levels of management or feeding.
- Even with a concerted effort to record accurate pedigrees, many situations can compromise the accuracy of pedigree information, including:
- In a naturally joined single sire joining mob there is always a possibility of another bull (known or unknown) mixing with the mob at some stage.
- Artificial breeding technologies can add considerable source of errors, particularly if the backup bull is put in soon after the AI program and there is not be a clear break in calving between the AI calves and calves sired by the backup bull.
- “Mothering up” cows and calves may be compromised by mismothering, particularly in first calf heifers.
- Human error when recording the mating details either from natural or artificial breeding programs.
Collecting performance data with minimal variation
- At certain times there may be little variation within a group to enable evaluation of the genetic differences. An example of this is ultrasound scanning young, lean bulls or cattle effected by significantly dry seasons.
- When animals are scanned or weighed when they are not in adequate condition (i.e. they are too lean), the usefulness of the fat depth and IMF measurements is considerably reduced.
- In these scenarios, scanning or weighing cattle is of little benefit as a means of identifying animals that are genetically different
Solutions to commonly encountered problems
- Become a proactive performance recorder, planning ahead of time as to what traits you will measure on what groups of cattle and when you will collect the data
- Consider using some sires that will have calves in other performance recording herds and mix cows after mating to ensure they calve with a range of AI sires and natural mating sires withing the one group
- Verify all outlier and excluded animals that appear on reports after each TACE analysis (fortnightly)
- Restrict calving windows to 6 -8 weeks where possible and manage the groups of cattle in as large groups as possible and take any performance records prior to splitting mobs for any other management reasons e.g. Take all 400 day weights on bulls before removing any for mating duties
- Carefully consider applying management groups to those groups of individuals that require them such as animals on higher levels of nutrition , animals that have become sick or are being managed differently where it will effect the performance measurement being taken
- Consider using DNA technology for parent verification and genomic testing. Using genomics in a whole herd strategy will allow more comparison of animals due to the ability to compare animals ( across the breed, not just the herd) that share a similar combination of gene markers with other animals with a genotype. An additional advantage can be expected by obtaining information on traits earlier in the animals life which may contribute to a higher EBV accuracy level ahead of selection decisions.
For more information on creating a proactive performance recording strategy please contact Angus Australia’s extension team.
Jake Phillips, Extension Manager