Interpreting EBI to maximise genetic gain in your herd

EBI (Economic Breeding Index) is a measure of the genetic potential of an animal. Research was undertaken by Teagasc to validate whether EBI is delivering at farm level using E-profit monitor data. As a result, the research findings have shown us that for every €1 increase in EBI this will result in a €2 gain in net profit/ cow. So, cows with an EBI of €100 are leaving €200 more profit per lactation in comparison to cows with an EBI of €0. The Index is comprised of seven sub-indexes with milk production and fertility being the two most prominent 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 €78. In addition, farmers should look at the herd average milk kg figure. This is an indicator of the genetic potential for milk kgs of the cows in your herd. The majority (over 60%) of herds nationally are minus for milk kg and can still deliver very acceptable yields of milk solids.

Fertility Sub-Index

Fertility remains the major driver of improvements in milk solids yield at farm level and few herds have the genetics for fertility solved. Herds with higher fertility sub-index are more genetically fertile and as a result, they are more likely to have lower empty rates and calve more compactly. The Teagasc target for spring calving dairy herds is to aim for a fertility sub-index of at least €75, that’s close to the herd average of €80 of the next generation herd.

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, teagasc are recommending a target of €40 for the bull team average. It’s important to note that as bull 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.

Health

The health sub-index can be used to identify bulls that will breed healthier cows. Greater cow longevity and the likely more restrictive access to antibiotics for treating mastitis and lameness and at drying off that will result in an increased emphasis on health traits. Teagasc have set a target of greater than €5 for the bull team with all bulls to be at least positive for 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), this will minimise the risks of EBI figures fluctuating and will result in a 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, always choose bulls from the DBI Active list. This index will allow farmers to select suitable beefs bulls to use on their dairy cows that will produce progeny with higher carcass value and higher calf value. To maximise overall profitability, use bulls with the highest DBI. For calving ease & short gestation, use bulls with the highest calving sub-index. For calving ease on heifers, use bulls with the highest calving sub-index which have the lowest % calving difficulty on dairy heifers, with high reliability.

Click Here to view the Active Dairy Beef Index List

In conclusion, 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 > €250 EBI (which may include a suitable bull at €200 or a bull up at €300). For herds using stock bulls for the breeding season, you should ensure the bulls are genotyped. Selecting high EBI GS bulls equally on the herd remains the appropriate choice for profit focused dairy farmers.