Dairy tests genomics to unlock genetic gain in crossbred herds
© Rhian Price Media Conwy dairy producer Eurof Edwards believes genomics will fast-track genetic gain in his split-block crossbred herd.
Eurof milks 180 spring-calving cows and 120 autumn calvers at the 149ha (368-acre) Rhydeden Farm in North Wales.
Cows weigh 500kg on average and produce 480kg of milk solids, with 4,000 litres supplied from forage last season.
See also: Advice for managing a split-block calving herd
Farm facts: Rhydeden Farm, Conwy, North Wales
Eurof Edwards © Rhian Price Media
- 149ha, owned and rented, all grassland
- 300 New Zealand Friesian and Jersey-cross cows
- 6,000 litres at 4.7% butterfat and 3.75% protein
- Somatic cell count of 120,000 cells/ml
- Cows milked through a 24/48 swingover parlour
- Supplying South Caernarfon Creameries
- Empty rate of 7%
- Feeding 1.3t concentrate a cow a year to autumn calvers and 0.8t to spring calvers
- Employing one person full-time and one part-time
Since returning to the farm alongside his father, Alun, and late uncle, Ifor, five years ago, Eurof has expanded the herd from 200 cows and tightened the two calving blocks from 12 weeks.
Although he was happy with the business’s trajectory, he reckoned genomic evaulation would be a cost-effective way to drive genetic improvement.
“The business is in a good place, but we want to improve the cows. Genomic testing is a means of making genetic gain as fast as possible,” he explains.
Breeding policy at Rhydeden
Heifer replacements are only bred from the spring block to aid calf management, with sexed semen used on the best animals.
“Producing all heifer replacements in the spring has streamlined management. It’s also cheaper to rear heifers in the spring, because we can get them out to grass,” says Eurof.
Last year, dairy sexed semen was used for four weeks for spring calvers, followed by Aberdeen Angus semen and a Stabiliser sweeper bull for two weeks.
The autumn portion of the herd calves over nine weeks, although the aim is to shorten this to six weeks.
Currently, 89% of autumn cows calve within the first six weeks, and the block has already been condensed by three weeks.
Empty cows from the spring herd are moved to the autumn block, and autumn-calving cows are served exclusively to beef.
This means any cows with poorer fertility do not produce replacements, Eurof says.
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Genomics project
Eurof genomically tested heifers in 2024 as part of a Farming Connect project. He used NMR’s GeneEze, which cost £25 a head.
A cohort of 50 heifers was tested, however, he only received genomic evaluations for 30 animals because the remainder were crossbreds.
At the moment, crossbred genotypes cannot be evaluated, so heifers must start milking for performance to be measured.
This is set to change later this year. AHDB Dairy now has about 500,000 female genotypes from various breeds, including several thousand from crossbred cows, which will act as a reference population.
Dr Daniel Pitt, animal genetics manager at AHDB, says to produce a genomic evaluation, the animal’s genotype is compared to an SNP key (a single nucleotide polymorphism or genetic variation, developed using markers identified in the DNA) to assess good and bad traits.
Initially, evaluations will be available for the key traits, such as production, cell count, maintenance and fertility, but AHDB aims to expand this to the complete evaluation.
Currently, 42% of UK milk-recorded herds are genotyping their females, with genomics tripling the reliability of evaluations to 58%, when compared with the parent average, and therefore improving farm profitability each year, Daniel explains.
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There is a £193 difference in profitable lifetime index (PLI) between herds genomically testing up to 25% of heifers and those testing more than 75%, he says.
In a 180-cow herd, this equates to £20,000 annual profit.
“The return on investment is massive when you compare it with the price of a genomic test.” Typically, testing costs £22-£35 a head.
Daniel points out that at Rhydeden, one heifer had a parent average PLI of £481 but only scored £79 for the more reliable genomic PLI, so her potential was much lower than it first appeared.
“It may be just the occasional outlier, but there can be large swings that will affect breeding decisions.”
Eurof will continue to select for three breeding traits: fat and protein, fertility and feed efficiency. He aims to match milk solids production to cow weight.
“The plan is to rank all cows and heifers together and breed replacements from the best genetics.
“It will help with first-lactation cows as well, because we won’t have a full lactation from them by the time we serve them,” he adds.
Carbon footprint
It is hoped that genomic testing will also positively impact the farm’s carbon footprint. This is because more productive, efficient animals can be identified sooner and retained in the herd.
The farm is one of 160 UK farms participating in an EU-wide Climate Farm Demo project.
This seven-year project will create baseline carbon audits for each farm, so they can understand what changes must be implemented to help the agricultural industry meet emissions reduction targets.
John Langley-Randall from Adas, one of the project co-ordinators, says Rhydeden Agrecalc data revealed the farm’s emissions stand at 0.82kg carbon dioxide equivalent (CO2e) a kilogram of fat- and protein-corrected milk.
While this is lower than the industry average of about 1.2kg CO2e/kg, the project has highlighted that the farm’s greatest source of emissions are feed digestion, purchased feed and manure management.
These are common top sources for livestock farms, says John, adding that genomics will help reduce this.
“Productivity increases make a big difference [to emissions] – by selecting animals that are resource efficient and reducing the number of unproductive animals, we can improve productivity.”
Eurof Edwards, Daniel Pitt and John Langley Randall were speaking at a recent event hosted by Farming Connect at Rhydeden Farm.