Harper Adams University to lower carbon footprint through ProCROSS crossbreeding

Improving herd longevity

The 400-Holstein cow herd is on track to meet its ambitious plan, achieving a carbon footprint of 0.9kg carbon dioxide equivalent per litre of energy-corrected milk (ECM), substantially lower than the UK average of 1.25kg.

However, Ruminant Sector Manager Kate Robinson believes ProCROSS breeding may unlock even greater potential.

“We want to improve herd longevity from our mean herd parity of 3.1 lactations,” says Kate. She adds that the plan to improve longevity is to sell heifers rather than ‘make room’ within the herd.

The plan is to calve the crossbred animals in a tight autumn block and manage them alongside the Holsteins.

“Speaking to other farmers that have ProCROSS within a Holstein herd, I’m hoping it will help boost constituents and they will be hardier and longer lasting.”

ProCROSS is a scientifically proven, three-breed rotational crossbreeding concept that combines VikingHolstein, VikingRed, and Montbéliarde to optimise hybrid vigour at 86%.

A proportion of VikingRed and Montbéliarde calves are already on the ground, allowing the university to compare growth rates.

The crossbred calves have grown better than Holsteins born at the same time, despite being fed and managed the same way.

ProCROSS boosts calf performance

The University will run an identically managed sub-herd of 60 ProCROSS cows within the 400-milking cow herd.

Currently, they have 32 F1 heifer calves. These were born in September and October 2024 from heifers and cows eligible for service the previous December and January. Heifers were served to VikingRed and cows to Coopex Montbéliarde.

Calves were housed in individual hutches before being transferred to group hutches of five from six weeks of age. They were fed 7.2 litres of milk replacer (mixed at 150 g/litre) before being weaned at 8-10 weeks based on concentrate intake and weight. Calves must be double their birthweight plus 10kg and eating 2kg of concentrate/daily alongside chopped straw.

At seven weeks, a total mixed ration comprising chopped straw, grass silage, maise, and forage rye is offered. After weaning, the concentrate is gradually reduced to 1kg/day as calves gain weight and move up groups within the shed.

Calves are weighed monthly from birth, and Matthew Bolton, breeding specialist at Harper Adams, says it has been interesting to observe the differences between breeds.

Alongside being more vigorous at birth, both the VikingRed and Montbéliarde-sired calves have grown better than the Holsteins:

10 October-born Holsteins averaged 1.11kg/day from birth up to 19 March
12 Coopex Montbéliarde-sired calves averaged 1.24kg
15 VikingRed calves performed the best, averaging 1.32kg.

23% replacement rate

Heifer calves will be grazed on herbal leys once they reach 250kg, and small amounts of supplement will be offered. They will transition back onto TMR one month before service.

At Harper Adams, Holstein heifers are served at 400kg liveweight, with the age at first calving averaging 23 months.

“My guess is the Montbeliarde is going to reach service weight faster. The first-generation crosses will be synchronised in November and mated to VikingHolstein to get them in as tight of a block as possible to calve in September 2026,” explains Matthew.

Based on genomic test results and milk records, the herd currently runs a 23% replacement rate with heifers bred from the best animals.

“The top 15% of £PLI animals go to dairy, and I use a colour-coded box system to rank the remaining animals based on traits, says Matthew. “If they have good traits for lifespan, maintenance, fertility and health, they get a blue box. The more blue boxes they get, the higher they rank,” he adds.

Future goals and ambitions – ‘pushing boundaries’

The university farm, which undertakes extensive industry research, will be able to accurately compare the performance of the ProCROSS animals versus the Holsteins.

Feed efficiency, methane emissions, milk yields, youngstock growth rates and beef calf values will be closely observed. The short-to-mid-term goal is to lower the herd’s replacement rate to 20%.

“When we reduced the replacement rate from 24% to 23%, it saved us £42,000 in rearing costs, which is phenomenal,” says Kate. “If we can get down to 20%, our cost savings will be massive, and we will have more beef animals to sell.”

After two dairy services, cows are served with Danish Blue semen, and heifers are mated to Angus. Kate is also excited about the performance of beef calves born from ProCROSS.

The university closed its 60-cow robotic unit in October due to equipment becoming old and amalgamated most cows into its parlour-milked herd. The facility is currently being used for far-off dry cows.

However, with an increasing number of UK dairy farmers moving to autumn-block calving, Kate sees potential in reopening the unit, stocking it with ProCROSS cows, and grazing them.

“ProCROSS is genetically engineered to graze, but they will fit into our existing system perfectly,” says Kate. “We can show the industry and our students the different dairying options and how each system compares. We can do costs for both groups of cows, and we can dive deep into cow behaviour, health, and fertility,” she notes.

At first, ProCROSS will only make up a small proportion of the herd, but Kate sees potential in growing numbers.

“We are pedigree Holsteins, and we will always have to be that way to be industry comparative for research purposes, but we may increase ProCROSS numbers if we can submit a strong enough business case,” she ends.

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