The ‘Next Generation Herd’ was established to validate that genetic selection using the EBI will increase productivity and profitability under intensive grass based systems. At the Teagasc Moorepark Open Day in 2021, the research showed clear evidence that high EBI cows were delivering more milk solids per cow, better female fertility & lower carbon footprint, compared to the national average.

Dr. Andrew Cromie, has carried out recent research to try and replicate the Next Generation Herd analysis using  “commercial” herd data within the ICBF database. His analysis is consistent with the findings from the Next Generation Herd, showing that increasing EBI is having a positive impact on not only herd performance but also the carbon footprint of the national dairy herd.

When comparing the performance of the Elite Holstein Friesian Herd (€184 EBI) to the National Average Holstein Friesian Herd (€125 EBI), the Elite Herds outperformed the Average Herds by 15kg’s milk solids per cow.

Data extraction and methodology

Herd summary data was collected from 13,500 dairy herds using 2021 HerdPlus reports. The source of this information was as follows:

  • Co-op performance reports
  • EBI Reports
  • Dairy calving reports

Additional data was also extracted from the ICBF database at a herd summary level, such as health traits, dairy inseminations, and dairy beef records

Herds were then selected based on the following criteria:

  • Only Spring calving herds were selected for more accurate comparative analysis.
  • Herds were categorised by EBI (i.e. top 10%, average and bottom 10%).
  • Only Holstein Friesian herds were used in the analysis to eliminate any heterosis effects.
  • Herds were also categorised by herd size.

Based on the above criteria, 2,677 herds which incorporated 308,000 cows were included in the study.

1.  Impact of Herd EBI on Key Performance Indicators

The Initial analysis was based on Herd size of between 100 and 200 cows (130 cows on average). (see Table 1)

Based on this analysis, the Top 10% of herds on EBI, when compared with the Average EBI herd had:

  • 365 litres higher yields
  • 43kgs better milk solids
  • 33k lower SCC
  • Better fertility (11% better six-week calving rate and 9 days shorter calving interval)
  • Higher replacement rate (+2%), but similar parity/age structure

This analysis is very consistent with the outcomes from the Teagasc Next Generation Herd study.

Table 1: Herd Performance by EBI category

2.  Impact of Herd EBI, across different Herd Sizes

The following analysis looked to compare herds across different herd sizes i.e. (i) less than 100 cows, (ii) between 100 and 200 cows and (iii) greater than 200 cows (See Table 2).

It is clearly evident from Table 2 that EBI works regardless of the herd size, with similar levels of performance across varying herd sizes in each EBI category.

Table 2: Breakdown of performance based on Herd Size

3.  Impact of herd EBI when comparing Top 2% vs Top 10%:

When comparing the top 2% vs top 10% of herds (see Table 3), the analysis shows that increasing herd EBI will result in continued improvements in milk solids per cow and female fertility (i.e., % calved at two years and six-week calving rate). While there has been good improvements in the % calved at two years and six-week calving rate, that there has been no continued improvement in calving interval days.

Other research, by the ICBF genetics team, has shown similar trends with the national Calving Interval figure (i.e. improving, but at a slower rate than previous).  Therefore, improving the current female fertility evaluations has been a major focus of ICBF and Teagasc teams over the past 2 years. This new fertility evaluation will place a greater focus on compactness of calving traits which will bring about further improvements and accuracy. It’s hoped to publish these new fertility evaluations in 2023.

Table 3: Breakdown of performance comparing high EBI herd

4.  Production of farm emissions (CO2e) & Sexed Semen usage:

When carrying out a comparative analysis on farm emissions and dairy inseminations, Table 4 shows that high EBI herds have a lower Carbon Footprint. Focusing on EBI will have a positive impact on achieving  the 22-30% reduction in emissions by 2030 in Ireland.

When looking at sexed semen about one-third of herds are currently using sexed semen. As expected, levels increase with increasing herd size. This still only makes up 10-12% of total dairy inseminations. It is important we try to increase the usage of sexed semen within the next few years. With 90% of pregnancies resulting in heifer births, this in turn will allow farmers to use more beef semen selecting high Dairy Beef Index bulls, which will provide long term sustainability for the Irish Dairy Industry.

Table 4: Herd CO2 emissions and Sexed Semen usage

5.  Impact of EBI on Carcass weights and Cow Efficiency:

Analysis of 2021 dairy steers slaughter performance, based on EBI and cow efficiency (see Table 5), showed there is no evidence of any real change in Carcass weight/age with increasing herd EBI.

Cow liveweights were also recorded in twelve high EBI herds. For the twelve herds in question the average mid-summer liveweight for cows was 560kg. The level of weight recording on dairy herds is very low and it is an area for improvement, higher levels of data recording are required to improve cow efficiency accuracy.

Table 5: Performance of Dairy steers and Cow efficiency based on EBI

6.  Impact of EBI on Health Traits:

After reviewing data collected on health traits (see Table 6). There is currently no evidence that High EBI herds have higher incidence of mastitis and/or lameness events. High EBI herds make up 5-6% of lameness events and 7-10% of mastitis events recorded on the ICBF database.

However the level of data recording was low with 20% of small and average sized herds recording health traits and less than 10% for larger herds. This is an area that needs to be reviewed in order to increase the data recording of the mentioned health traits.

Table 6: Impact of EBI performance on lameness and mastitis incidence


A detailed analysis was undertaken to “future-proof” the EBI, based on the use of commercial herd data, from within the ICBF database.

Strict editing prior to data extraction was applied to ensure that all herds and animals were being compared within “like for like” systems. For the purpose of this comparative analysis, herds were categorized based on their sizes. Herds were selected using the following protocol: (i) Compact spring calving herds and (ii) Holstein Friesian herds

Within all the systems examined, there was clear evidence that high EBI Holstein Friesian herds were more profitable & sustainable. This was mainly through (i) higher milk solids, (ii) better fertility performance. These results are consistent with the Teagasc Next Generation Herd outcomes.

The analysis has also highlighted a number of areas for further follow-up/examination, including; (i) Female fertility in the future, especially at higher levels of EBI (ii) Green House Gas goal trait for the future, focusing on carbon footprint or gross emissions (iii) Increased farmer recording of some traits of critical importance in the future, for example; cow live-weight, mastitis & lameness.

ICBF and Teagasc are always open to “evolving and updating” the EBI, based on outcomes from both research and field data. We welcome continued engagement & feedback in this regard.