How a switch to Irish dairy genetics could improve fertility

More and more block calving herds are capturing the “phenomenal” fertility benefits of Irish genetics, which are proving relevant to both spring and autumn-calving systems in the UK.

The economic breeding index (EBI), launched by the Irish Cattle Breeding Federation (ICBF) in 2001, rates cows on suitability for spring-calving, grass-based systems, with fertility weightings of 24% on calving interval and 11% on survival.

A change of tack from the residual breeding index (RBI), the EBI strives to synchronise cow dry matter intakes and milk production, explains Gareth Davies, grassland expert and UK manager at Ireland Genetics UK, who has witnessed how successful EBI animals can be in autumn-calving herds.

“Certain farms with winter milk contracts want high fertility rates to maximise peak milk production over the peak milk prices of November, December and January and to hold a calving pattern to maximise the milk price you need to be calving to hit this period,” says Mr Davies.

“Most UK contracts give you benefits for producing milk at winter and in block-calving systems you need to be holding a calving pattern to match the milk price curve or the grass growth curve.”

Efficiency and lifetime production

The spring calving index (SCI), launched by AHDB Dairy in August last year, selects for smaller, long-lasting cows of about 500-550kg producing upwards of 4,500kg/year from grass, which is similar to New Zealand’s breeding worth index and the EBI.

Mr Davies says, in general, Irish cows bred to realise 0.8kg milk solids/kg bodyweight, meaning 440kg milk solids a lactation from a typical 550kg cow that lasts five to six lactations on average.

“Longevity and fertility are key to lifetime production,” he adds.

“The difference between the first and second lactation yields are 14% and subsequent lactations yield 22% more milk than lactation one.

“These smaller cows are efficient converters too.

“If you’re feeding 15kg of 11.5ME grass to a 500kg animal you could expect around 18 litres, whereas from a 700kg animal you might only get 13 litres.”

From a UK standpoint, Mr Davies rates the SCI, but urges farmers to look at EBI due to the wealth of data available from Ireland’s predominantly spring-calving, grass-based dairy industry.

EBI v breeding worth index

Cheshire dairy farmers Ed and Barry Dale have been selecting Irish cows on EBI information since first buying a batch of 150 in-calf heifers in 2009 and subsequently incorporating them into both their spring and autumn-calving herds.

The past three years have seen the spring calving herd’s empty rates drop from 18-19% to 13% and calving has remained in a tight 11-week period.

“In 2009 we went to Ireland to look at over 300 cows, taking notice of EBIs before we started,” says Ed, who ran a comparison with New Zealand cows bought the same year.

Both batches of about 150 animals had their first lactation in 2010, with about 12% of animals surviving into their sixth year on the farm.

“We are breeding a cow that will get in calf easily, be easy-care, do well in a grass-based system and we do want her to have reasonable milk solids because we have one eye on the future,” says Ed, who supplies Sainsbury’s through Wiseman, being paid for fat but not protein.

Ed says there is no difference in breeding approaches between the spring and autumn herds, with EBI cows working well in either system.

“We are replacing 25% of the herd every year but 10% go as tidy in-calf heifers to transition into another calving pattern or are sold,” he adds.

In 2009, Ed and Barry were seeking cows with €40 (£28) or more for fertility and milk and EBI ratings of €100 (£70) or more. Ed now benchmarks cows at twice this, aiming to buy cows with a score higher than €200 (£140) for EBI and rated at least €80 (£56) for milk and fertility.

“You need to know how the EBI is split,” advises Ed. “A cow of 217 EBI could be rated high because of milk production. In an ideal world she has fertility of around €90 [£63], milk of around €90 and all the rest make the gap up.

“We have a lot of New Zealand Friesian crosses and Jersey cross Friesians,” adds Ed, who is halfway through a two-year outcrossing period using Norwegian Red bulls, after which EBI bulls will be “strong contenders”.

See also: Economic breeding index drive Irish herd improvements

All about the economic breeding index

What is it?

Economic breeding index (EBI) is a single-figure profit index aimed at helping farmers identify the most profitable bulls and cows for breeding dairy herd replacements.

It comprises information on seven sub-indexes related to profitable milk production. These are milk yields, fertility, calving performance, beef carcass, cow maintenance and management and health.

How does it work?

A national database combines the efforts of the National Cattle Breeding Centre (NCBC),Ireland’s Agriculture and Food Development Authority (Teagasc) and the Irish Cattle Breeding Federation (ICBF). Three genetic evaluations are undertaken every year, the norm internationally, with economic breeding index (EBI) weightings reviewed annually.

Donagh Berry, livestock genetics expert at Teagasc, has seen the industry-wide benefits of EBI. “Irish farmers are clearly seeing fertility improvements in their herds and almost exclusively attributing this to EBI,” he says.

“I really believe it has had a phenomenal impact.

“Teagasc does the research, the ICBF does the genetic evaluations and runs the index and the NCBC is responsible for the breeding programme.”

One of the benefits of the Irish system is that all breeds are rated on one base, facilitating the adoption of cross-breeding strategies.

Without this, Dr Berry says it is easy to embark on a cross-bred programme with the belief of progress when in fact you might be going backwards.

“Having a single base allows all breeds to be compared so it allows a farmer to assess a Jersey bull, for example, which might offer him heterosis but would lose so many PLI [profitable lifetime index] points, making this a questionable move,” he explains.

And while EBI is intended to suit low-input systems, Noel Gowan, dairy consultant at Grasstec, says there is enough information in the sub-indexes to make EBI relevant to any breeder.

“This is even true for year-round calving,” explains Dr Gowan.

“Whether you have Holsteins or cross-bred cattle, whether you are driving for 10,000 litres or 5,000, fertility is key.

“A year-round calver could look at high predicted transmitting ability milk bulls and see which of those were also high fertility bulls – it’s applicable across the industry.”

Suiting Irish farms

With about 90% of Irish dairy farms spring calving to hit the grass growth curve, the EBI is geared to get a high proportion of Irish calving from mid-January to mid-April, explains Dr Gowan.

And this brings simplicity to farm management, allowing youngstock to be raised in batches.

“Simplicity very often means efficiency and a compact calving makes better use of resources on the farm, particularly labour,” he adds.

Once calving intervals are sorted, there is still the issue of managing dry matter cover. For this, Dr Gowan champions nine core targets for spring-calving farms to remember.