Aberdeen-Angus Indexes
Choosing a bull is a financial decision
A bull bought this year will continue to earn or cost money three years from now. Estimated Breeding Values (EBVs) have always told you how a bull should perform trait by trait. What they do not tell is which of two bulls is the better buy overall.
This is what an Index does. It combines the traits that matter, scores each by what value they offer to a commercial farmer and gives a single £ figure to compare.
What the number means
Index values are expressed in £s of expected profit per calf born.
The figure is made to be compared. If Bull A has an Index value of £120 and Bull B of £70, it should be expected that each calf from Bull A returns around £50 more than a calf from Bull B, once calving, growth and carcass performance are accounted for. Over four years at 30 calves a year, that is a difference of £6,000.
The index is not a mark out of a hundred and there is no pass line. Higher figures are better figures.
How to read it
Every bull is placed in one of five bands alongside his figure, so you can see where he sits in the breed without having to hold the whole population in your head.
- Top 20% and upper middle are your strongest options
- Middle is a typical Aberdeen-Angus bull
- Lower middle and bottom 20% will cost you against the alternatives
Current band cut-offs are published on the bull list and are refreshed at each evaluation run. They move upward over time as the breed makes genetic progress, so a bull's band can change even when his own figure has not. That is the index doing its job. The bar rises.
What goes into the Dairy Beef Index
The Dairy Beef Index is built for one job: choosing an Aberdeen-Angus bull to go across a dairy herd. It reports an overall figure plus three sub-indexes, so you can see where a bull's strength lies.
Calving. Calving ease and gestation length. If you are milking cows, these are not negotiable, and nothing in the overall figure should persuade you otherwise.
Growth. 200-day weight, 400-day weight, carcass weight and daily feed intake. What the calf puts on, and what it costs to put it on.
Carcass. Carcass conformation, fat class and intramuscular fat. Intramuscular fat is the marbling that carries flavour and juiciness, and it is what the consumer expects when they buy Aberdeen-Angus. The industry is only beginning to pay for eating quality, but the Index recognises the genetics that deliver it.
Read the overall figure first and the sub-indexes second. A bull can reach a good overall figure by different routes, and the route matters to your herd.
How it was built
The trait weightings come from a bio-economic model of commercial dairy-beef production, built for the Society by AbacusBio.
In plain terms, the model works out what a one-unit change in each trait is genuinely worth to a commercial farmer, using real feed costs, real long run average carcass prices and the actual distribution of Aberdeen-Angus cattle on the EUROP grid. A kilo of carcass weight is worth what a kilo of carcass weight earns. A difficult calving costs what a difficult calving costs, including the vet, the labour, the milk that cow will not give and the risk of losing her.
Those economic values are then combined with the Society's own performance records, drawn from more than a million UK trait measurements.
The model will be reviewed as costs and prices move. Beef prices in 2026 are not beef prices in 2020, and an index that ignores that stops being useful.
What the index will not do for you
Young bulls carry less certainty. A bull with no progeny on the ground has a figure built from his ancestry. It is the best estimate available, but it is an estimate, and it will move as his calves perform.
It is an average, not a promise. The index tells you what to expect across a bull's calves, not what any single calf will do.
It does not replace your own eye. Structure, temperament, feet and whether the bull will actually work across your cows are still your call. The index narrows the field. It does not choose for you.
See the figures
View the current Dairy Beef Index bull list
Updated at each evaluation run.
Also coming
The Dairy Beef Index is the first of three Aberdeen-Angus indexes. A Maternal Index and a Terminal Index, built on the same economic model, will follow later this winter. Each answers a different question, so use the Index that matches what you are aiming for.