Our return visit finds Jonny Slack's operation in the midst of breeding season, with innovative heat detection systems and careful genetic selection driving the farm's future.

The fields of Eden Valley are notably drier than usual as we make our second visit to Dolphenby Farm in Cumbria. Following our spring visit during calving season, we've returned to see how this progressive 550-cow dairy operation approaches its crucial breeding period, a time that will determine the farm's productivity and profitability for years to come. 

Co-run by Jonny Slack, who advanced from relief milker to business ownership just two years ago on this tenanted farm, Dolphenby Farm continues to demonstrate how thoughtful management and strategic breeding decisions drive success in a modern grazing operation. 

Precise Heat Detection Systems 

As the 12-week spring calving period winds down, attention has shifted entirely to breeding. Dolphenby employs a comprehensive approach to heat detection that blends traditional methods with modern technology. 

"We start our pre-breeding preparations three weeks before service begins by tail painting all cows red," Jonny explains. "We then tail paint blue as heats are identified." 

This visual system has recently been supplemented with a newly installed collar system, providing additional data points for more accurate detection. The combination allows for precise timing of services, critical for maintaining the farm's tight calving pattern. 

Strategic Service Decisions 

Rather than applying a one-size-fits-all approach to breeding, Dolphenby Farm uses the LIC Tracker to identify the top and bottom 25% of the herd as a starting point for breeding decisions. 

"The Tracker gives us genetic information, but it doesn't account for days calved or difficult calvings," Jonny notes. "We use the data as a foundation but rely on our eyes and instinct for the final decisions." 

The farm maintains a streamlined approach to servicing. "To keep things clear and efficient, we select a 'sexed bull of the day' and all cows chosen for dairy replacements receive that bull's genetics," Jonny explains. "The remainder are served to beef, which has become a significant profit centre for us." 

Premium Genetics Driving Performance 

Continuing their strategic blend of genetics, Dolphenby remains focused on Irish Holstein Friesians and F15 crossbreeds that deliver high milk solids and volumes. 

The genetic approach is paying dividends, with early season milk yields peaking at 29 litres and consistently achieving at least 27 litres at 2.45 kg milk solids, strong evidence of proper peak production. This performance reinforces the farm's decision to maintain larger animals (550-575kg) compared to traditional New Zealand-style grazing operations. 

"We're even seeing excellent genetics coming through in some of our older cows – fifth and sixth calvers – so we're using conventional straws on them to capture those qualities," Jonny adds. Their conventional straws are achieving impressive 75% conception rates. 

Managing Weather Challenges 

The unusually dry spring, while initially advantageous for the Cumbrian operation, has begun to create challenges as the breeding season progresses. 

"We've had no rain in the area, so we're concerned about potential impacts on conception rates," Jonny explains. "When grass growth slows, we need to increase bought-in feed, especially during serving when good nutrition is essential for successful conception." 

The farm faces the dual challenge of managing potential heat stress and maintaining adequate nutrition during this critical period, refusing to compromise on feed quality despite the additional costs.