Richard W. Todd and N. Andy Cole

USDA-ARS

Conservation and Production Research

Laboratory

Bushland, Texas

G. Robert Hagevoort

New Mexico State University

Clovis, New Mexico

Kenneth D. Casey and Brent W. Auvermann

Texas AgriLife Research and Extension

Amarillo, Texas

Open Lot Dairy Ammonia Losses and

Nitrogen Balance: A New Mexico Study

Partially funded by USDA-CSREES

Special Research Grants AG09-

4288 and 2010-02674.

Regulatory Pressures

0

50000

100000

150000

200000

250000

Eastern

New

Mexico

West

Texas

Milk

Co

w P

op

ula

tio

nGrowth in Southern High Plains Dairies

2000 2013

Objectives

• Quantify NH3 emissions from open lot and lagoons

• Build dairy nitrogen balance – stores and flows

• 3492 total cows – no calves

• 80% lactating – consumed 90% of N fed

• Feed averaged 16.7% crude protein

• Produced 29 kg milk head-1 d-1

22.5 ha

1.8 ha

Ammonia Emissions Quantified

• Ammonia flux: Inverse dispersion analysis (Flesch and

Wilson, 2005) using WindTrax (ver. 2.0.8.8, Thunder Beach

Scientific)

• Atmospheric NH3 concentration: three Open Path Lasers

(Gasfinder 2, Boreal, Inc.)

• Turbulence characterization: two 3-axis sonic

anemometers (Model 81000, R.M. Young)

Nitrogen Partitioning

• N intake and milk N by cow class (dairy management

provided) and NH3-N loss (measured)

• Cow N retention, milk N and N excretion calculated as

functions of DMI (Castillo et al., 2000)

Sonic anemometer

Lagoon OPL, 233 m

z = 1.15 m

DOY 219-223

East OPL, 334 m, z = 1.0 mWest OPL, 225m, z = 1.0 m

North 2 OPL, 314 m, z = 1.0 m

North 1 OPL, 314 m, z = 3.4 m

Sonic anemometer

Sunshade

Milking parlor

Feed alley, with

flush lanes on

either sideSolids separator

and stockpile

Feed storage

and mixing

N

Canal to lagoonsLagoon OPL, 239 m

z = 1.15 m

DOY 224-227

12

3

• 3500 total cows

• 80% of total milked

• Produced 29 kg milk head-1 d-1

• Fed 16.6% - 17.4% crude protein

Laser path, DOY 219-223, 233 m

Laser path, DOY 224-227, 239 m

Met tower

No

water

3

2 1

• Methane concentration

• Wind and turbulence variables

• Inverse dispersion model

Day Of Year

219 220 221 222 223 224 225 226 227 228

Am

mo

nia

flu

x d

en

sity (

g m

-2 s

-1)

0

50

100

150

200

Ammonia Flux Density

Open Lot

Ammonia Flux Density

Lagoons

Day Of Year

219 220 221 222 223 224 225 226 227 228

Am

mo

nia

flu

x d

en

sity (

g m

-2 s

-1)

0

50

100

150

29 mm rain

Hour

0 4 8 12 16 20 24

Am

monia

em

issio

n r

ate

(kg d

-1)

0

500

1000

1500

2000

2500

Before rain

After rain

Ammonia Emission Rate

Open Lot

Hour

0 4 8 12 16 20 24

Am

mo

nia

em

issio

n r

ate

(kg d

-1)

0

20

40

60

80

100

120

140

160

180

Before rain

After rain

Ammonia Emission Rate

Lagoons

SourceEmission rate

(kg d-1)

PCER

(g cow-1 d-1)

Fraction of

N intake (%)

Open lot 1061 (252) 304 41

Lagoons 59 (39) 17 2

Ammonia Emission Means

• Late summer – expected peak annual emissions

• Adult cows – lactating or pregnant dry cows

• Most manure deposited on open lot

Caveats

Study LocationPer capita emission rate

(g animal-1 d-1)

Open lot, whole farm, summer

Todd et al. (2015) New Mexico 321

Bjorneberg et al. (2009) Idaho 190

Moore et al. (2014) California 140-199

Leytem et al. (2011) Idaho 127

Freestall barn or barn+open lot, whole farm, summer (except Cassel et al.)

Leytem et al. (2013) Idaho 332

Flesch et al. (2009) Wisconsin 93-100

Cassel et al. (2005a) California 50 (winter)

Cassel et al. (2005b) California 103 (spring)

Cows

Milk

Manure/Lagoons

NH3-N

2.0%

43.1%

35.9%

19.0%

Dairy Nitrogen Balance

612

116 (123)

Excreted N12 484 (465)

264

NH3-N

Milk N

220 (201)

N in

Manure,

Lagoons

Open Lot Dairy Nitrogen Flow

(g N cow-1 d-1)

Measured/Calculated

(Castillo et al.)

Residual

Feed N

Estimated Annual Emission

Study Location Wintertime

emission:

Summertime

emission

Mukhtar et al. (2008)Open lot dairy,

east Texas53%

Todd et al. (2008, 2011)Beef feedlot,

west Texas59%

Estimated Annual Emission

SeasonPCER

g cow-1 d-1

Fraction fed N

%

Summer 321 43

Winter 189 22-26*

Annual 255 30-35*

* Range of N feed intake from 600 to 700 g N cow-1 d-1

Conclusions

o High emissions during study

• 321 g NH3 cow-1 d-1

• 43% of fed N

o Manure management critical

• 95% of NH3 emissions from open lot

• Where N is excreted and how handled

plays important roll in determining NH3

emissions