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ILVO press release - Thursday, February 1, 2018

1 February 2018 @ILVO: ammonia reduction plan press conference

... with Flemish Minister of Agriculture Joke Schauvliege and Chair of the Farmers’ Union (Boerenbond), Sonja De Becker
New perspective on the ammonia reduction plan (PAS): feeding strategy
Lower protein in the ration of meat cattle can cut the ammonia concentration nearly in half

ILVO now has hard numbers that show how digestion of protein in the rumen of meat cows affects the amount of ammonia emitted. If a Belgian Blue heifer gets 2% less raw protein in the ration, the ammonia emissions drop by a whopping 40%. The difference for animals that normally received a high protein concentration even reached 50% reduction. No negative effects on growth were observed during the experiment.

Bedding and cleaning management appears to have little or no effect: higher or lower cleaning frequency and/or bedding changes did not result in important differences in emissions in the ammonia-reduction experimental animal housing. Furthermore, different types of bedding (flax-loam instead of wheat straw) did not appear to be effective as an anti-ammonia strategy.ILVO’s goal in this research is to find possible alternative management strategies for meat cattle because this group currently only has one strategy suggested in the current regulations, namely pasturing.

Urgent need for PAS research in the meat cattle sector

Currently, meat cattle farmers required to reduce their ammonia emissions in the context of the Flemish ammonia reduction plan (PAS in Dutch) have little or no options. Sonja De Becker (Boerenbond – Farmers’ Union): “Meat cattle farms that must reduce their ammonia emissions can only implement pasturing in combination with (partial) empty barns. There is only one measure available, which is not appropriate for the meat cattle practice, for example fattening bulls. But tailored reduction possibilities must serve to prevent loss of family farms. We have dedicated a first phase of co-funding of €200,000 together with the Flemish Government to support research focusing on ammonia reduction in meat cattle husbandry.”

Starting in 2016, this ILVO research project, which took place in the new PAS experimental barn, had a two-pronged approach: to target ammonia emissions at the source, namely via protein in the ration, and reduction of emissions from manure via stall management. In Flanders, meat cattle normally housed on bedding and less on grates. Low-emission floor systems and floors with grates in combination with a manure robot or manure clean-up are not appropriate for meat cattle.

Precision feeding is good for emissions and the pocketbook

Despite knowledge that ammonia emissions in ruminants are directly related to protein metabolism in the rumen, no feed regulations have been listed as part of the ammonia reduction plan. In two ILVO feeding experiments, a high-protein diet (14 to 15.7% raw protein) and a low-protein diet (11.5 – 12.7% crude protein) were fed to Belgian Blue heifers. These experiments show a strong effect of the crude protein and intestinal digestible protein level in the ration on ammonia emissions. A drop in crude protein of 2% resulted in a drop in ammonia emissions of nearly 40%. The differences in ammonia concentrations between both treatments even reached 50% at times.

The amount of protein in the ration, especially for growing animals, cannot be reduced completely without negative production results. In these ILVO experiments, the reduction of crude protein had no negative effect on the growth of the heifers, because they did receive enough rumen degradable protein. Karen Goossens (ILVO researcher): “The low-protein diet will, over time, almost automatically result in a shortage of intestinal digestible protein. These long-term effects have not yet been studied.” Sam De Campeneere (Scientific Director, Animal Husbandry, ILVO): “Playing with protein levels in the ration will require stricter attention for the ration. But refining the protein and saving on crude protein will also result in savings on feed costs.”


ILVO communication:, M. 32 486 26 00 14
ILVO-PAS research:, T. 32 9 272 27 84
ILVO meat cattle research:, T. 32 9 272 26 10