BREEDPLAN EBVs work
Meat & Livestock Australia March 22, 2024
One way to evaluate whether BREEDPLAN EBVs accurately predict the performance of an animal’s progeny is through a well-designed progeny testing program. In this scenario:
- Bulls with known divergent BREEDPLAN EBVs (e.g. High/Top and Low/Bottom) are mated to cows of similar genetics.
- The progeny from these bulls are raised together (this eliminates potential environmental differences in performance).
- The progeny are measured for the trait(s) of interest.
The following calculations are then made:
- The EBV difference between the Top and Bottom EBV sires.
- The difference in progeny performance between progeny of the Top EBV sires and progeny of the Bottom EBV sires.
It is expected that the difference in the average performance of the two groups of progeny will be half of the difference in the EBVs of the sires (half because only half of the genetics of an animal comes from a sire; the other half comes from the dam). The process of evaluating EBVs using this method is shown in the diagram below:
Consider the following example using 200 Day Weight EBVs:
- The average 200 Day Weight EBV of the Top EBV sires is + 36 kg and the average 200 Day Weight EBV of the Bottom EBV sires is +11 kg. This gives an EBV difference of 25 kg (36 – 11).
- As only half of the EBV difference is passed on to the progeny, we would expect the average difference in progeny performance to be 12.5 kg (25 kg/2).
- When the progeny are measured for 200 day weight, the average difference between the progeny of the two groups is 11 kg. Therefore, the EBVs of the sires have provided an accurate prediction of progeny performance.
The above example is from a structured progeny test run by the Australian Brahman Breeders Association, where BREEDPLAN EBVs generated for sires were compared against the observed performance of their progeny. The table below shows the results for a number of traits from this same progeny test.
Trait | Expected Performance | Observed Performance |
200 Day Weight | 12.5 kg | 11 kg |
400 Day Weight | 17.5 kg | 17 kg |
600 Day Weight | 23.5 kg | 27 kg |
Scan Eye Muscle Area | 2.35 sq. cm. | 4 sq. cm |
Scan Rib Fat | 1.2 mm | 0.5 mm |
Scan Rump Fat | 1.6 mm | 1.4 mm |
As you can see, the EBVs consistently provide an accurate prediction of progeny performance. Similar studies have been conducted in different breeds, both in Australia and overseas.
Optional reading: Further information on evaluating BREEDPLAN EBVs, including additional proof of profit studies, can be found in the Do EBVs Really Work? article. Angus Australia have also published results from their Angus Sire Benchmarking Program, which includes evaluation of BREEDPLAN EBVs. More details can be found on the Angus Australia website here.
Key message
BREEDPLAN EBVs provide an accurate prediction of progeny performance. They are underpinned by validated science.