Future proofing farm infrastructure
Richard Tucker considers the options for replacing his loose housing with cubicles and a new slurry system to help with of management for his 222 spring calving cows at Ditchetts Farm in Devon.
David Ball, AHDB Buildings and Environment specialist offers his thoughts about the options, considering cow comfort and current regulations as well as rapidly changing environmental requirements.
Replacing loose housing with cubicles
The Tucker family built a new loose housing shed in 2015 and enabled an increase in cow numbers and to feeding on the pad when necessary. An extension isn’t possible due to the topography and limits on the grazing platform.
The move to cubicles would make management much easier and accommodate up to 240 cows while meeting Red Tractor requirements.
The main considerations for cubicle layout are feed and water space, cow flow, cow comfort, stocking rate and bedding material.
There is capacity to divide shed into three groups of 81 cubicles with space for scraping out and adequate water troughs and feed space.
Cow bedding materials
The slurry system may dictate the bedding type and Richard is less keen on sand due to the extra handling and is looking at mattresses with sawdust or lime-based material on top.
The bedding options for the three-month period when the cows are housed:
- Straw yards 1,800 kg per cow
- Sand 1,450 kg per cow
- Chopped straw on a cubicle mattress 225 kg per cow
- Sawdust on a mattress 90kg per cow.
Cubicles mean lower bedding requirements, easier environmental mastitis control, reduced worked, high stocking rates and easier to manage cows in groups.
However, there would be higher capital costs and slurry storage requirements. And an increased risk of injury to the animals due to the increased infrastructure in the shed.
Options for slurry storage
Richard wants slurry storage solution that works for his spring calving system. As tenants they need to keep the landlord happy and location is an issue since they are close to the main road and other buildings so a lagoon isn’t an option. They also want to avoid pumping it and prefer to use gravity if possible.
They need to consider various rules and regulations such as planning, Environment Agency, NVZ (part of the farm is within an NVZ so five months of storage will be required), SSAFO regulations and Farming Rules for Water.
Calculating slurry storage capacity
Based on Richard’s herd size and current yield, his cows will produce 832 cubic metres of slurry during the 3-month housing period.
Parlour water goes elsewhere but there is rainfall on dirty yards, the roof, muck store and feeding area to be considered. This would add an additional 652 cubic metres meaning minimum storage requirements of 1,484 cubic metres.
Our Slurry Wizard enables you to calculate storage requirements and weigh up different options.
The government’s Clean Air Strategy suggests that by 2027 that all slurry stores need to be covered and environmental permitting will be required by 2025.
Other considerations are odour, health and safety, spreading equipment and new design standards for cattle buildings to reduce ammonia emissions. Involving the Environment Agency early in the planning process will enable them to help with these aspects.
Slurry store construction costs
Typical costs range from £5 per square metre (£32 per cow) for a clay lined lagoon up to £40 per square metre (£250 per cow) for a concrete store.
Richard’s plan is to construct a store roughly 30 metres by 14 metres by digging into unused ground in front of, and below the new shed to enable it to be filled by gravity. This area also has relatively easy access.
Making the best use of nutrients
A typical tonne of 6% DM slurry contains 2.6kg of nitrogen, 1.2kg of phosphate and 2.5kg of potash which is equivalent to £3.30 per tonne based on today’s fertiliser prices.
Each cow will produce the equivalent nitrogen as 55 kg of ammonium nitrate during the three-month housing period. The new slurry store will therefore contain as much N as 12 tonne of ammonium nitrate by turnout. However, it’s not all readily available to the crop so having adequate storage capacity will allow the most efficient use of the nutrients through careful timing and application rates.
Ditchetts Farm update - 17 September 2020
Calving started on 7th February with 82% calved in six weeks.
February was wet, followed by a dry March and April which led to supplementary feeding. Rain in June and July helped the grass grow and favourable late season conditions have provided enough silage for winter.
Existing calf housing was updated to address ventilation and labour demands. In early lockdown, two smaller sheds were knocked down and replaced with one building to improve calf rearing.