Background Dairy farm
One cow toilet against nitrogen emissions is not the other
'Pot training' for cows. This naturally appeals to the imagination and the news about a German investigation attracted a lot of media attention. But how useful is that in farming practice? Boerenbusiness spoke with Paul Galama, project leader 'Manure separation in existing dairy barns' of Wageningen Livestock at the Dairy Campus in Leeuwarden, where systems are being investigated to separate manure and urine in order to reduce ammonia/nitrogen emissions.
Galama attended the presentation of the German research at a conference in Switzerland 2 weeks ago. During the research at the Forschungsinstitut für Nutztierbiologie, calves were taught to urinate in a fixed place by rewarding them with food or punishing them by spraying them with water. This was successful in 11 of the 16 calves. "We already knew that pigs are toilet trained, there are already pig toilets," says Galama. "It is interesting that we know that you can teach cows something, but the question is: how do you do that logistically on a farm with 100 to 150 cows? You get quite a lot of cow traffic."
Toilet in the concentrate box
In that respect, he believes a different type of cow toilet (Hanskamp CowToilet) that is being tested on the Dairy Campus offers advantages. That is not in a separate room, but in the concentrate box. The cow gets a bowl under its tail that moves gently. Because a nerve is hit, the cow has the urge to urinate. "The habituation goes fairly quickly," said Galama. "An average cow excretes 35 liters of urine and 45 liters of faeces in a day. More than a third (35%) of the urine can be collected in the cow toilet."
According to Galama, there are a few companies that use this system in practice and it can also be combined with other techniques. The final emission factor of the cow toilet will be determined next year. "But it seems that an emission value of 8,4 kilos of ammonia per cow per year is feasible. The question is: do we think that is enough?"
Two more source separation techniques are being tested in the barn on the Dairy Campus. One of them turns out to be wrong. This is a rubber floor consisting of flaps and gutters that the dairy farmer can place on the slatted floor in combination with a feeding sidewalk. The emission measurements show that there is insufficient reduction of ammonia emissions from both the basement and the floor. Galama: "There are all kinds of floor systems on the market: with slots, holes, made of concrete, asphalt or rubber. We thought that rubber was easy to keep clean and robust, but the emission reduction is disappointing."
Permeable tile on grid
Galama expects a lot from the third method: the permeable tile on a slatted floor. "The advantage is that you don't need a separate room, you can improve the walkability of the floor and you collect all the urine. And… you don't have to train cows."
With the permeable tile floor you collect all the urine in the cellar, the cloth on the floor determines whether faeces particles pass through. At first, the results were also disappointing, the ammonia emission was even higher than in the reference barn with slatted floor. Galama: "Urine has a pH value of 9, if you can lower that to about 5,5 pH, then you have a large reduction in ammonia emissions. Adding sulfuric acid lowers the pH. The acidified urine in the cellar can you can also use it again to rinse the floor Acidification of slurry is not as popular but if it is just urine you need a lot less acid If you run it on the land then you have less emissions You have to use it view in its entirety: stable, storage and use."
Acidification perspective
In addition to ammonia, nitrous oxide and methane are also measured. The techniques have hardly any influence on the reduction of methane emissions, while this was expected with the stable floor systems. The results of the acidification are listed in October and November. "But it's perspective." Acidification will soon be stopped and other methods will be investigated in combination with the tile floor, such as extracting air from the basement.
Are the developments fast enough for the dairy farmer near Natura 2000 area who sees buying out or even expropriation or the taking away of the permit? Galama: "We deliberately opted for solutions that you can use in existing barns. Most livestock farms have cubicle barns with a grid and cellar. You don't have to wait for new construction, so it can be done fairly quickly."
The 'Manure separation in existing dairy barns' project started in October last year and is financed by ZuivelNL, the Ministry of Agriculture, Nature and Food Quality and the relevant business community. The Dairy Campus hopes to continue the research next year. Funding for this has not yet been finalized.
Linda van Eekeres
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