"Colloque Lille 2017" Séquence 9.2

1. Ammonia (NH3) in
Norwegian dairy herds
Lars Erik Ruud
Associate professor
lars.erik.ruud@inn.no
N
HH
H
• Dairy
• Advisory service

2. Ammonia – NH3
• A poisonous gas with distinct and unpleasant odour
• Has local effects on mucosal surfaces
– Associated with respiratory problems in animals and humans
• Negative environmental effects; acidifying, eutrophying
and is a source of the greenhouse gas N2O
• Density is approx. 59% of atmospheric air

3. NH3
ppm Symptoms
7-10 Negative effects of long term exposure
5-15 Odour threshold humans
20 Irritation of eyes in broiler
30 Irritation of eyes and respiratory tract in animals and humans
50 Reduced production/ yield, watery eyes
70 Fast reduction of growth and very poor feed utilization
100 Increased respiratory rate, edema of the lungs
5000 Lethal in minutes
Several studies shows negative effects:
Occupational exposure limit (N): 15 ppm (8h/day)
Regulations on keeping cattle: 10 ppm

4. [Gustavsson, 1988]
What is the source of NH3?
Emmission
Production

5. The source of NH3?
During degradation
of proteins and
nucleic acids
nitrogenous waste is
formed
Ammonia
Urea
Uric acid
[Mod. after Gustavsson, 1988]

6. The source of NH3?
Stable atmosphere
(emmission)
Litter/ manure
(production)
During degradation
of proteins and
nucleic acids
nitrogenous wastes
are formed
Ammonia
Urea
Uric acid
NH4
+
Ammonium
NH3
Ammonia
pH –
increase
pH –
decrease
Gaseous
NH3
[Mod. after Gustavsson, 1988]
NH3 -concentration
in the stable
atmosphere
Ventilation

7. NH3- consentration varies with
• pH in manure (animal species, feeding etc.)
• N-surplus in manure (feeding)
• Air temperature and relative humidity
• Dry matter in manure
• C/N – ratio in bedding material
• Soiled area (m2 wet by urine)
• Ventilation
• => Housing design («technical sorroundings»)

8. Objective
• To measure NH3-concentration in Norwegian
dairy herds
• Investigate associations between housing
design and NH3-consentration

9. Method
• Mean for recorded value
measured central on feed bunk,
activity area and resting place
= NH3-consentration
• «Barn design», cleanliness,
feeding and more was recorded
during one winter-time visit
(minimum ventilation rate)

10. t-test/ ANOVA was used to evaluate
differences between different design etc
[Micro IV, GfG instruments]

11. Material
• 62 herds from the central east Mjøs-region (n=31),
Nordland (n=6) or north-west Norway (coast) and Sør-
Trøndelag (n=25)
• Visited once by a trained technician from Tine or a
technician from HINN during the winter 2012 – 2013
• 109 ± 59,8 animals; 49 ± 21,6 lactating dairy cows
• 2002 [1975 – 2012]; 87 % loose housing (free stalls)
• One herd was excluded because of extreme values due
to aeration of NH3-treated straw inside of the barn
60°N
70°N

12. Results (n = 61 herds)
• Mean NH3-concentration: 4,5 ppm [0 – 20,2 ppm]
Regulation on keeping cattle; 90 % <10 ppm
Occupational limit; 98 % <15 ppm
Occupational limit (<2002 -> 2024); 2 % >15 ppm

13. «Negative» results (no associations)
• Feeding (composition of the meny)
– TMR/PMR vs roughage & concentrate fed separately
• Herd size
• Housing system (loose housing vs tie stalls)
• Flooring (slatted floor vs solid floor)
• Open vs closed connection between manure storage and the animal
room (traditionally manure are stored in cellar)
• Sloped alley floor vs flat floor
• Animal crowding/ m2 and m3
• Type of ventilation system; natural, guided natural or mechanical
• Location of ventilation fan; cellar, wall or pipe

14. «Positive» results (significant association)
• Fully insulated > non-insulated and low-insulated
buildings
• System for urine drainage < without
• RH% + indoor temperature < 90
– capacity/ adjustment of the ventilation system
• CO2 (capacity/ adjustment of the ventilation system)
• Low indoor temperature < high indoor temperature
• Clean stalls < dirty stalls (cleanliness and management)

15. Tendencies (p = 0,06-0,10)
• Compost bed < other housing systems
• Natural ventilation < mechanical ventilation

16. Discussion
• Lower concentration than expected (feared)
Hygiene=> the main source for NH3-formation is removed
Urine drainage=> a source for NH3-formation is removed
Compost bed=> manure is absobed, pH, C/N-ratio
RH% + ind. temp (90-rule) => Ventilation capacity/
adjustment = Increased air exchange
Uninsulated => NH3 is evacuated through roof
openings because NH3 has lower density compared
to atmospherical air

17. • No effect of fan in cellar or open connectionon on NH3-concentration
– …because density of NH3 is < density of atm. air
• Confirmed by the lower NH3 concentrations when naturally ventilated (open
ridge)
• NB! Other gases have other effects, e.g. H2S (hydrogen sulfide) that has a
higher density than atm.air
– «Manure gases» ≠ NH3
– Different gases has to be handled independently
• The housing design may influence on NH3 concentrations,
however also cleaning routines (management) has positive effects

18. Conclusion
• Uninsulated/ low insulation
• Natural ventilation
• High ventilation rate (>90)
• Cleanliness routines
• Urine draining systems
• Reccomended ventilation rates
for fully insulated barns
Important to achieve low concentrations
Worth further investigation

19. Thank you for your attention!

20. Cow cleanliness

21. Stall cleanliness
• 1 - Clean
• 2 - Some dirt
• 3 - Dirty
• 4 - Very dirty

23. Mechanical scraper on slatted floor

24. …may be automatic as well !