EBI or the Economic Breeding Index is a measure of the genetic potential of an animal. Research by Teagasc was undertaken to validate if EBI is delivering at farm level using E-profit monitor data. The research findings have shown us that for every €1 increase in EBI will result in a €2 gain in net profit/ cow. So, cows with an EBI of €100 are leaving €200 more profit per lactation than cows with an EBI of €0. The Index is comprised of seven Sub-Indexes, milk production and fertility are the two most valuable traits in the index.

Milk Sub-Index

When selecting on milk sub-index, Teagasc have included a threshold figure of ≥€50 for individual bulls.  This is easily achievable as the average milk sub index for the top 75 bulls is more than €95. Look at the herd average milk kg-this is an indicator of the genetic “milkiness” of the cows in your herd.

Fertility Sub-Index

Fertility remains the major driver of improvements in milk solids yield at farm level. Herds with higher fertility sub-index for fertility are more genetically fertile and as result are more likely to have lower empty rates and calve more compactly. While fertility of the national herd is improving, it is still far from industry targets on the average Irish dairy farm. ICBF and Teagasc have set a target of greater than €120 for the bull team average and a threshold figure of ≥€80 for individual bulls.


Calving Sub-Index

The Calving Sub-Index will help to identify easy calving bulls and lower mortality rates. When selecting bulls for the calving sub index, it is important to note that as team calving sub-index increases, the gestation lengths are declining as follows:

The reason why gestation length is declining with increased calving sub-index is because approximately 50% of the value of the calving sub-index is coming from shorter gestation lengths. Many farmers are starting caving earlier than planned in recent years. The combination of improved herd fertility and shorter gestation length means that many farmers are delaying the start of breeding.


The health sub-index can be used for to identify bulls that will breed healthier cows. Greater cow longevity and the more likely restrictive access to antibiotics for treating mastitis and lameness and at drying off will result in increased emphasis on health traits. Famers should target a health sub index of ≥€10 for the bull team average with all bulls at least a positive figure for the health sub-index.

Team of Bulls is Critical

Teams of bulls should be used equally not only on cows but on heifers as well. Over-reliance on one or more sires is risky. By using bulls in a team (especially young GS bulls) will minimise the risks of bulls falling in EBI and will result in higher reliability (95%) for the overall bull team.

Guidelines for Bull Team Usage

The following 3 steps will help you pick the right sires for your herd:

  1. Check your HerdPlus EBI Report for the genetic indexes of your herd and identify which traits you wish to improve.
  2. Select a Team of bulls from the ICBF Active Bull List that are on average better than the genetic index for the traits you wish to improve.
  3. Use the HerdPlus Sire Advice tool to allocate the selected bulls to the cows in your herd.

Dairy Beef Index

For dairy farmers using beef AI this Spring, Use the Dairy Beef Index (DBI) to select suitable beef AI sires for your dairy herd.  This index will allow farmers to select suitable beefs bulls to use on their dairy cows that will produce progeny with higher carcase value and higher calf value. To maximise overall profitability, use bulls with the highest DBI.

A team of bulls should be selected that suits the various dams in your herd (i.e., maiden heifers, young cows and mature cows) and the number of these that are selected for beef AI. Bulls with higher beef merit figures should be selected for older animals. Use bulls that are classified as “LOW Risk of Dairy Heifer Calving Difficulty” on heifers. Click Here to view the Active Dairy Beef Index List.

In short, EBI has made a significant contribution to profitability and sustainability on Irish farms over the years. Provided you are selecting bulls with a figure that is better than the herd average, genetic gain will be made. ICBF and Teagasc are recommending using a team of bulls ≥€270 EBI (which may include a suitable bull at €200 or a bull up at €300).  Selecting High EBI bulls equally on the herd remains the appropriate choice for profit focused dairy farmers.

Bull selection Guidelines