NUTRITION ▶▶▶
Influencing rumen microbes improves nitrogen efficiency
Feed additives can increase nitrogen efficiency and decrease NH3 emissions. Proper rumen function, the right protein–energy balance in the rumen and more intestinal digestible protein can also help.
BY JANET BEEKMAN
Feeding potato pulp as an addi- tional source of energy and Pro- tispar, which contains essen- tial oils, tannins and saponins from plants, im- proves protein use.
E
xperts agree that improving nitrogen use on dairy farms demands a comprehensive approach. Dairy farmers can decrease ammonia emissions by taking several measures. In addition to optimising dairy ra-
tions, 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 Dijkstra, senior cattle feed lecturer at Wageningen Univer- sity & 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 sub- optimal and nitrogen will disappear into the urine. “On aver- age, 75% of the ration consists of roughage. Good quality roughage that provides a lot of energy is the basis of success- fully decreasing nitrogen emission. The final steps in this pro- cess 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.
The results of additive
enhancement are strongly dependent on the type of ration and the quality of roughage and concentrates
The effects of different measures Wilfried van Straalen, researcher at Schothorst Feed Re- search, says that different measures affect nitrogen emission. “Additives can contribute to this, but do not expect any mira- cles,” 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 cal- culation 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 supply products directly to dairy farmers. “We decide on the compositions ourselves because we have extensive knowledge of raw materials,” says
32 ▶ DAIRY GLOBAL | Volume 8, No. 1, 2021
PHOTO: ANNE VAN DER WOUDE
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