EBI delivering productivity, profitability and sustainability

The breeding objectives on farms vary but all of them include key priorities including improving milk production, fertility, health and disease resistance, and profitability. Each of these issues is influenced by different factors. Milk production, for instance, in terms of yield as well as milk solids, is greatly determined by the genetics in place in the herd, as well as the overall nutrition including grass, silage and concentrate usage. There are balances to be struck. There is high heritability for increased milk volumes, for instance, that automatically delivers higher milk solids volumes. Higher profitability, however, is delivered by milk solids percentages, not volumes. We learned to our cost before the introduction of the Economic Breeding Index (EBI) that high milk volumes can have a negative impact on fertility. Isolated breeding decisions can lead to counterproductive outcomes and a balanced approach using all available herd performance information is the key to successful breeding programmes over many years.

A fertile approach

On the fertility side, the logic for seeking improvements in the herd fertility status is to breed cows that have multiple lactations and that will cycle every year to deliver optimum production in a seasonal production system. Other important aspects of the make-up of an efficient cow are more challenging objectives in the breeding process. Somatic cell counts, lameness and vulnerability to diseases such as TB can be positively influenced by breeding policy, but to a lesser extent and by lower margins than the headline production and fertility figures.

Lower carbon – higher profits

There are now additional requirements being brought into play that will be given increasing priority in the coming years. The somewhat nebulous concept of sustainability will be manifested by lower environmental impact, particularly the ability to use the breeding tools and EBI to breed cows with a lower carbon footprint. The science is advancing at speed with full recognition that cows can be bred to produce higher milk solids per kilogramme of input. Add in another priority to deliver higher beef merit offspring from the Irish dairy herd and it is easier to understand the complexities of breeding management and the multiplicity of sometimes competing aspirations and preferred outcomes envisioned based on decisions being made in the weeks ahead.

Comparing average and top-end

The key to success is planning and using the array of tools available to make decisions that will have positive or negative repercussions on individual herds for generations of cows in the coming years. The informed use of the EBI in breeding decision-making is the key to success. Figures produced last year by the Irish Cattle Breeding Federation (ICBF) show the difference between average and top-end herd EBI figures. The dependability and deliverability of the index is improving incrementally, year on year. Figures produced last year showed the performance differences between the top EBI and the average herd. The key performance indicators included the average milk (litres) per cow. The top 20 per cent of herds averaged 5,663L per cow while the average herd yield was 342L behind at 5,321L per cow. Average milk solids further highlighted the EBI differences with the top herds averaging 47kg greater milk solids production per cow. In the background, other important breeding traits were contributing to these physical performance figures. The top 20 percentile EBI herds had an average calving interval of 367 days compared to the average 385-day performance of the average EBI herd. Likewise, there was a significant discrepancy in the average six-week calving rate with the top herds having 79 per cent of their cows calved in the first six weeks compared to only 67 per cent of the average EBI herds calved at that critical period. The higher performances of the top herds were also seen as delivering a bonus in environmental terms. Kilogrammes of CO₂ per kilogramme of fat and protein corrected milk (FPCM) was measured at 0.86 for the high EBI herds compared to 0.91 for the average herd. This is not only a win for environmental sustainability. It has a significant economic value with more efficient cows delivering greater output from similar inputs.

On-farm experience

Moving to a practical herd strategy, much depends on current genetics and long-term breeding targets. Last year, Teagasc used the example of the Goresbridge-based Donohoe herd to show how long-term breeding policies can deliver impressive results over time. Philip Donohoe has been a keen advocate of the EBI since its inception 20 years ago. Calving interval, fertility and milk production have all improved significantly over the two decades. The Donohoe herd produced over 500kg of milk solids per cow in 2022. It had a calving interval of 365 days and a six-week calving rate of 85 per cent. Every year pre-breeding, Philip puts considerable time into choosing his dairy bulls. The ICBF Sire Advice Programme is used to provide direction and strategy in making those bull choices. In essence, Philip can reasonably predict the EBI figures for his heifer replacement calves before conception. The sire-advice tool enables him to match the right cow to the right bull with the aim of maximising genetic gain.
While keeping an eye on fertility, a major focus of Philip’s breeding strategy is to improve fat and protein percentages. The longer-term goal is to ultimately breed a herd with an average 5 per cent fat and 4 per cent protein. He also chooses bulls which are positive for health and disease resistance, as well as carbon footprint reduction.

Spreading the bull risk

One important aspect of choosing a range of bulls to use in a breeding season is to have a sufficiently large group that any variabilities in reliability are diluted through the average performance of the bulls on a herd. A rule of thumb is to allocate up to seven bulls used equally across a herd of 100 cows. This selection takes time and planning, well before the breeding commencement date. Booking semen well in advance is also an absolute necessity. The short breather between calving and breeding must be used to re-energise ahead of breeding, even after a spring that has tested farmers to the limit.