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Precision breeding pays performance dividends (April 23)

A data-focused breeding strategy is driving genetic gain and performance for one Somerset-based herd. We find out more about their approach and the results so far.


Combining breeding tools and innovative herd management technology is generating useful data for herd progression and genetic gain for Jack Coombes and his family.

With his brother Sam and father Barry, Jack runs a 280- cow herd, plus 250 followers, near Yeovil and has recently begun using sexed semen and has adopted genomic testing to help improve longevity and future-proof his business. The fully-housed herd calves all year round, and averages 10,500 litres per cow, at 4.2% butterfat and 3.4% protein. Milk is sold on a Müller-Tesco contract.

The Coombes family has been working closely with Cogent’s Graham Higgott to implement a sexed and beef strategy, to increase genetic gain in the herd, maximise profit and create a stronger overall breeding plan.

In 2017, the former NMR Silver Salver winners made the switch to using sexed semen on heifers, progressing also to using it on cows in 2020.

At the same time they also began using PrecisionMAP, Cogent’s customised herd-auditing tool, which looks at the requirements of the herd’s milk contract, combined with each cow’s performance and conformation data.

Genomic testing

The data allow the Coombes to identify genetic trends, and areas of genetic gain within the herd, to help plan for the future. The milk contract is based on yield, rather than milk constituents, so the herd’s best genetics to fit these requirements are selected.

Drawing on the farm’s AHDB Dairy Herd Genetic Report, the tool ranks the herd using the Cogent Custom Index (£CCI). This is made up of 80% PLI and 20% milk contract data.

The PrecisionDNA genomic testing service, which Jack implemented at the same time, means he has been able to make breeding decisions based on genomic information of the herd.

“We currently have more heifers than we need, which is why we also decided to go down the route of genomic testing to select the best for breeding replacements,” he explains.

“Bovine TB is a significant problem in this area so we aim for a heifer surplus in case we lose any cows. But we are now only breeding from the best. We aim to produce 80 replacements each year, and we are happy with our numbers now we’ve tightened up our breeding.”

Herd-auditing tool: data supports precise breeding decisions

A small tissue sample is taken from all youngstock for genomic testing and this provides Jack with an accurate picture of their genetic potential, and an idea of how his heifers will perform as cows from as early as a few weeks old. The results can identify milk production, health and fertility data, and various other negatively associated markers.

Genomic information also now includes Cogent’s proprietary feed efficiency index, EcoFeed, which measures feed conversion. This allows Jack to make breeding decisions based on the feed efficiency of individual animals.

Sire selection

Jack opts to use Cogent’s Precision Match (CPM), which helps him match every animal’s weaknesses with the most complementary sires, and also rules out inbreeding. Dairy sires are selected for around 30% of the milking herd, which are predominantly first-, second and third-lactation cows.

“The top 70% of maiden heifers coming through are put to sexed dairy, and 30% go to beef. Older cows, usually those past three lactations, are put to beef because this allows new genetics to come through the herd,” explains Cogent’s Graham Higgott.

“The Coombes prioritise mobility, fertility, udder and breeding performance,” he says. “Cow longevity is also important – the herd has bred 16 100-tonne cows to date – and type and PLI should not be too high. Ultimately, they’re looking to use well-balanced sires that will produce commercial cattle and a uniform herd.”

Herd performance: the Coombes aim to breed heifers that mature into long-lasting and productive cows

Barry and Jack do all their own AI, using Ultraplus dairy sexed semen, and achieve first-service conception rates of around 43%.

Starting their 'precision' journey in 2020, first-lactation heifers are now coming through the herd, with £CCI data demonstrating on-going improved performance with each generation.

“The £CCI of the first-lactation heifers shows a £316 genetic gain, heifers between 12 and 30 months old are now showing an increase of £435, and those less than 12 months old are showing a genetic gain increase of £500,” says Graham.

For the percentage of the herd served to beef semen, the Coombes opt for easy-calving British Blue and Aberdeen Angus bulls. They typically have 100 beef calves at any one time, and these are kept on a separate holding. Feeding capabilities and infrastructure mean they aim to keep them for between 12 and 18 months, before selling as stores through nearby Sedgemoor market, or sometimes to Buitelaar.

The next steps for the Coombes, in terms of breeding, include looking into greater use of sexed male beef genetics, to achieve a better return for beef calves and contribute to the overall increased profitability of the business.

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