Frequently Asked Questions

What do EBVs mean?

EBVs are a measure of the genetic merit of your animal. Each EBV is given in the units of the trait, so a carcase weight EBV of +10kg means that the animal has the genetic potential for a carcase weight which is 10kg more than the breed group (either continental or native) average. Their calves with inherit half of this (and half from their other parent).

Bars to the right show an animal is better than average.

  • For traits we want to increase (e.g. productive lifespan or calf survival), bars to the right are more positive, meaning higher genetic potential.
  • For traits we want to reduce (e.g. age at first calving or days to slaughter), bars to the right are more negative, again meaning better genetic potential.
  • There are some traits which some farmers want to increase but others might prefer a decrease. This is particularly the case for Fat Class. For these traits, bars to the right simply show a higher value, so for fat class, a bar to the right means the animal has the genetic potential for a higher than average Fat Class.

How reliable are these EBVs?

Alongside each EBV, we also give the accuracy (Acc). This is a percentage between 0-100%. Higher values mean that the estimated breeding value is more likely to close to the true genetic merit. We only publish EBVs with accuracies above 30% for carcase traits and 25% for maternal traits. We get higher accuracies when:

  • We have more performance data for the animal and more of its relatives.
  • We can better account for non-genetic factors. This is easier to do when animals are kept on larger farms.
  • The heritability of the trait is high. This means that genetics plays a larger role in the trait.

Help – I’ve looked up my animal and it doesn’t have any EBVs?

Don’t panic. We use new data from BCMS, abattoirs and breed societies to publish new and updated EBVs multiple times throughout the year. To find a list of dates, click here.

We only publish EBVs with accuracies above a certain threshold (30% for carcase, 25% for maternal traits). This is so we can be reasonably confident that the EBV we provide is a good representation of the animal’s genetic merit. More data tends to increase accuracy so animals which don’t currently meet the threshold are likely to be published over time.

If your herd is particularly small or your animals have few relatives, it is harder for us to estimate their genetic potential and so it may take longer, or even not be possible for us to produce accurate EBVs.

I currently get EBVs for traits such as 400-day weight and eye muscle area from the breed society, which EBVs should I use?

Ideally, both sets if they have reasonable accuracy values. The existing EBVs are important tools for bull selection; the new traits provide an additional level of insight for those traits on which producers are paid.

How does this analysis take into account differences between farms?

In the same way as current pedigree breeding evaluations. Individuals reared together on the same farm at the same time are grouped into what we call contemporary groups. Genetic linkage between these groups is then used to compare their relative genetic merit.

What does “average” represent on the charts?

Native and continental breeds each get EBVs where a value of 0 is the average genetic merit of either native or continental-bred cattle that were born in 2017.

Can I compare EBVs between breeds?

The aim of this work is to advance within-breed selection. Cattle of the same breed type (continental or native) do have EBVs expressed relative to the same genetic base, so comparison within breed type is possible.

How can I increase the accuracy of my EBVs?

1. Always put sire details (UK ministry number) on the passport

2. If you are selling bulls, ask your clients to put sire details on the progeny’s passport.