Compare expected difference in progeny performance
Meat & Livestock Australia April 8, 2024
The demonstration animal we were looking at in the previous lesson ranked in the Top 5% of the population for growth at 400 days. By comparing the expected difference in outcome if two different bulls were used in a herd gives you an understanding of what this means in real terms.
Firstly, calculate the EBV difference between the two bulls. In the example below, there is a 20 kg difference between the 400 Day Weight EBV of the Demonstration Bull and Bull 2 (i.e. +52 kg – +32 kg).
What does this mean for the expected performance of their progeny? On average, half of the EBV difference will be passed on to the progeny of each sire (with the other half coming from the dam). Therefore, it would be expected that the progeny of the demonstration bull would be, on average, 10 kg heavier than the progeny of Bull 2 at 400 days of age:
While a 10 kg difference at 400 days of age may not be a large difference at the single calf level, most bulls are used over a mob of cows. For example, if the demonstration bull sires 50 calves, this 10 kg difference equates to a potential production difference of 500 kg in live weight (i.e. 50 calves x 10 kg) by the time his calves reach 400 days of age.