Experts agree that improving the nitrogen use at dairy farms demands a comprehensive approach. Dairy farmers can decrease ammonia emissions by taking several measures. In addition to optimising dairy rations, improvements in roughage crops, rearing youngstock and transition management are possibilities. Feed additives still play a limited role, but more independent research can change this.

What causes high nitrogen excretion?

Jan Dijksta, senior cattle feed lecturer at Wageningen University & Research, explains that when protein digestion in the rumen is too high, nitrogen excretion will be too high as well. Secondly, when there is too little energy in the cows’ rations, the conversion of amino acids into milk protein will be suboptimal and nitrogen will disappear into the urine. “On average, 75% of the ration consists of roughage. Good quality roughage that provides a lot of energy is the basis of successfully decreasing nitrogen emission. The final steps in this process can be taken with additives,” says Dijkstra, who points out that relatively limited independent research has been done into the effects of additives on dairy farming.

Different measures effect nitrogen emissions

Wilfried van Straalen, researcher at Schothorst Feed Research, says different measures affect nitrogen emissions. “Additives can contribute to this, but do not expect any miracles,” he says. “A recently published meta-analysis shows that tannins do have a positive effect on nitrogen use.”

He emphasises that the results of additive enhancement are strongly dependent on the type of ration and the quality of roughage and concentrates. “Adding slow-release urea and rumen bypass amino acids is only useful when the ration calculation shows that there is a shortage, and this is the first limiting nutrient.”

Agrinutrition is a Barents subsidiary, which is a wholesaler in raw materials. Its consultants directly supply products to dairy farmers. “We decide on the compositions ourselves because we have extensive knowledge of raw materials,” says Agrinutrition category director Bianca Meijerink. “We have been developing feed additives for years now based on market needs and practical research. Our motto is: “Farmers are the scientists. They prove that our products work and keep them on the market.”

Additives for environmental demands

According to Jan Speerstra, owner of Speerstra Feed Ingredients, additives can help to meet the ever-stricter environmental demands. They can also help to reach a better return on investment. “We keep speaking of ‘additives’, where in fact, they are additional animal feed. Using the rumen bypass amino acids lysine and methionine, more methionine and lysine are made available to the cow at a gut level. This improves the nitrogen efficiency and decreases nitrogen excretion. Dairy farmers can thus feed less protein without compromising on milk or protein levels.”

Targeted feeding of rumen bypass amino and fatty acids

Speerstra is very positive about feeding rumen bypass amino and fatty acids to dairy cows. “In pig and poultry farming, synthetic amino acids in feed are already used with considerable success. Feeding cows based on which specific amino and fatty acids they need concentrates the ration, improves nitrogen efficiency, decreases methane emissions, and contributes to more well-balanced milk fat. We are not yet ready for this in the Netherlands. In the United States however, they have been working with this for a longer period.”

Feed additives are not cheap. Prices vary from € 125 to € 500 per 100 kilogrammes. “You cannot compare these prices with those of regular feed.

Feed additive prices

Feed additives are not cheap. Prices vary from € 125 to € 500 per 100 kilogrammes. “You cannot compare these prices with those of regular feed,” says Eric Heemskerk, director at Ingenieursbureau Heemskerk. “They are used in very small quantities and they can save a lot on other expensive sources of protein, such as soy or rapeseed.”