Including the effect of methane reducing additives

With the NorFor release May 3, 2023 it is possible to calculate the effect of the methane reducing additives Bovaer® (active ingredient: 3-NOP) and SilvAir® (active ingredient: nitrate) on total methane production in lactating dairy cows. The reducing effect is calculated as a decrease in % from the basic NorFor methane production equation for both additives. This new feature will be found in the feedstuff table (FST) version 2.10, feed ration calculation (FRC) version 2.15 and one-day feeding control (OFC) version 1.43 and is available for all users of NorFor Feed Ration Optimizer (NFRO), DMS, Optifôr, IndividRAM, TypFoder and FoderOpti.


Bovaer10® contain 10% of the active substance 3-NOP that supress the enzyme in methanogens that form methane in the rumen. The active substance is broken down in a couple of hours in the rumen and therefore it needs to be added continuously in order to maintain the reducing effect on methane. Bovaer® was approved in the EU as a methane reducing feed additive to dairy cows in 2022. It reduces methane production by 20-40% depending on dose (Figure 1) and roughage type. Highest reductions are seen in diets with maize silage and high dosage. High roughage NDF in diets reduces the methane reducing effect and that is taken into account in the new methane equation in NorFor (Figure 2). Since the concentrations are extremely low, the product should be mixed into compound feed or mineral feed.


Figure 1. Tri-nitrooxypropanole (3-NOP) is an active substance that reduces enteric methane in dairy cows. The diagram shows an example when a ration has 200 grams NDF from roughage per kg total DM intake and a varying dose of 3-NOP.


Figure 2. Tri-nitrooxypropanole (3-NOP) is an active substance that reduces enteric methane in dairy cows, but roughage NDF slows down its effect. The diagram shows the fading effect on methane reduction of 3-NOP, when roughage NDF per kg total DM intake is increasing in the diet and has a 3-NOP dose of 60 mg per kg DM.


Silvair® contains nitrate (NO3) that works as an alternative electron acceptor that redirect electrons away from the methane production in the rumen. The reducing effect of nitrate increases with dose and in the NorFor equation a maximum effect is reached at a dose of 25 g NO3 per kg total DM intake (Figure 3). High doses can be used but the risk of nitrate being metabolized into nitrite then increase. Nitrite can be absorbed over the rumen wall and inhibit oxygen transport in the cow.


Figure 3. Nitrate is an active substance that reduces enteric methane in dairy cows. NorFor calculates the reducing effect of dietary nitrate on methane accordingly.