Research project Conventional and organic dairy goat farmers explore the potential of zeolite for ammonia emission reduction.

General introduction

At the conclusion of the ZEOGOAT exploratory research project, it appears that spreading zeolite (a mineral powder) in straw-bedded goat barns has a highly variable effect on ammonia emissions, raising serious doubts as to whether the product will ultimately be able to prove itself as a stable and reliable PAS measure. PAS measures are expected to achieve their reduction percentage year-round.
Goat farms currently have (only) one accepted, applicable measure on the PAS list, namely grazing in combination with leaving the barn empty. Goat farmers who already use zeolites in practice report positive effects of the product on animal health and barn climate (reduced odor). They requested scientific substantiation of the NH3 emission-reducing effect in preparation for recognition as a PAS measure. The measurement method chosen in ZEOGOAT (measurements at the level of the bedding using measurement covers) was suitable for exploring the potential effectiveness of zeolite as an NH3 reducer. Following any promising results in this phase, a follow-up phase with more systematic measurements at the barn level is needed, which entails a complex and expensive measurement campaign.

Research approach

The preliminary ammonia emission measurements using zeolites were conducted at two commercial goat barns. The chosen measurement method—involving the placement of measurement lids on the bedding surface in the pens where the goats were housed—was adapted from ammonia emission research conducted in poultry barns. In the first trial (method calibration), the method proved less suitable for a goat deep-litter housing environment. The researchers implemented the necessary methodological adjustments. The project tested the zeolites both as a bedding additive and as a feed additive. All in all, the goat barn measurements yielded an average ammonia reduction of 18% (bedding additive) and 16% (feed additive). However, the variation between the measurement results was strikingly large, which proved to be an obstacle to moving on to larger-scale research designs.
Incidentally, the researchers had observed similar peaks and troughs in earlier zeolite tests in cattle barns with deep litter. There, too, a hypothesis was that in humid ambient air, the zeolite particles capture and retain moisture rather than the evaporated ammonia molecules.
Project partner Wim Govaerts & Co additionally analyzed the economic impact, including potential positive effects on animal health and production. A simulation showed that the cost of zeolites can be more than offset if zeolites also yield zootechnical benefits, such as reduced lamb mortality and higher milk production.

Relevance/Valorization

The use of zeolites to reduce ammonia emissions in (organic) dairy goats is a promising avenue, but further research is needed into the causes of the wide variability in emission reductions, into better measurement methods (alternatives to measurement hoods), and/or into feasible measurement methods at the barn level.

Financing

EIP