Dairy - Stokman Farm, Holland
Outputs
Outdoor grazing
This farm provides an outdoor grass loafing area for the cows during the spring/summer period. The cows are offered this “Free Choice” and can access the loafing area whilst still being able to return to the building for milking and feeding. This has the advantage over Zero-grazing systems which are associated with higher than average lameness scores and knee swellings relative to other farm systems.
Flooring and ammonia emissions
The most common housing for dairy cows, particularly on larger farms, is the free stall system – where cubicles are provided for resting, and animals have the freedom to move to the feeding area on an open floor. Manure is primarily deposited onto a solid floor and Nitrogen emission from these floor systems is nearly all in the form of ammonia. Under warm conditions, nitrogen loss is high, with most of the urea transforming into ammonia and volatilising to the atmosphere. Under cold winter conditions, nitrogen loss is relatively low. On average, about 16% of the excreted nitrogen is lost from the free stall area.
On solid floors, floor shape and surface characteristics can influence ammonia loss. A small, 3% slope of the floor allows urine to drain away from the faeces, reducing ammonia emission by 21% compared to solid or slatted level floors. A double-sloped floor with a urine gutter in the centre can reduce ammonia emissions by 50%, and a grooved solid floor with perforations can reduce ammonia emissions by 46%.
The farm’s new dairy building has incorporated a floor design which has a gutter feature allowing improved separation of urine and faeces. This separation reduces the level of ammonia emissions from the slurry by a minimum of 30% over conventional flooring types. These measures are particularly important given the fact that the Dutch Government has set strict reductions in ammonia emissions for 2010.
Modern, well-designed facilities enable the cows to demonstrate their natural behaviours and free choice in a safe environment. The floor design of the facilities also minimises ammonia emissions.