Rick KohnRick KohnDepartment of AnimalDepartment of Animal

and Avian Sciencesand Avian Sciences

Feed Management to Reduce Feed Management to Reduce N and P Losses to the EnvironmentN and P Losses to the Environment

OverviewOverview

The role of animal feeding on The role of animal feeding on reducing N and P losses to the reducing N and P losses to the environmentenvironment

Use of milk urea nitrogen to track Use of milk urea nitrogen to track improvements in protein nutritionimprovements in protein nutrition

Incentive programs to improve Incentive programs to improve feedingfeeding

A simple farm modelA simple farm model

InputsInputs MilkMilkMeatMeat

LossesLosses

N loss = N inputs – N in productsN loss = N inputs – N in products

N loss = LossN loss = Lossairair + Loss + Losswaterwater + N + N22

Recommendation: Decrease total reactive N losses from farms.

N CyclingN Cycling

FeedHerdSoil

Forage NUptake N = 11 T/yrGrain P= 11 T/yr Milk N = 5.0 T/yrMeat N = .5 T/yrIntake

Manure N = 16.5 T/yrN unaccounted for = 13.75 T/yrLegume N = 5.5 T/yrFertilizer N = 2.75 T/yr

NN

Typical EfficienciesTypical Efficiencies

S u b - s y s t e m e f f i c i e n c y L o w H i g h

Animal Product N / Feed N .16 .24

Feed N / Soil Available N .50 .75

Soil Available N / Manure N .25 .50

Kohn, et al., 1997. J. Environmental ManagementKohn, et al., 1997. J. Environmental Management

N Losses per ProductN Losses per Product

0

2

4

6

8

10

12

Nitrogen Loss per Product N (kg/kg)

Level of Management

LowEfficiency

ImproveHerd

Feeding

ImproveCrop

Uptake

ImproveManure

Availability

HighEfficiency

Kohn, et al., 1997. J. Environmental ManagementKohn, et al., 1997. J. Environmental Management

Milk Urea NitrogenMilk Urea Nitrogen

Nitrogen MetabolismNitrogen Metabolism

Kohn, et al., 1997. MD Nutrition ConferenceKohn, et al., 1997. MD Nutrition Conference

Urine N vs. MUNUrine N vs. MUN

y = 12.54x

R2 = 0.72

0

50

100

150

200

250

300

350

400

450

0 5 10 15 20 25 30 35

Milk Urea Nitrogen (mg/dl)

Urine N Excretion (g/d)

Jonker, et al., 1998. J. Dairy ScienceJonker, et al., 1998. J. Dairy Science

Target vs. Observed MUNTarget vs. Observed MUN

02468

101214161820

0 100 200 300DIM

MUN (mg/dl)

ObservedTarget

Jonker, et al., 1999. J. Dairy ScienceJonker, et al., 1999. J. Dairy Science

Target MUNTarget MUNMUN Target Concentrations for

Holstein Herds

6

7

8

9

10

11

12

15,000 17,000 20,000 22,500 25,000

Rolling Herd Avg (lb/cow/yr)

MUN (mg/dl)

Kohn et al., 2002. J. Dairy ScienceKohn et al., 2002. J. Dairy Science

Lab DifferencesLab Differences

NIRS is not as repeatable as wet NIRS is not as repeatable as wet chemistrychemistry

After Sep. 17, 1998 MUN analyses were After Sep. 17, 1998 MUN analyses were reduced about 4 units.reduced about 4 units.

Check ListCheck List

✓ Milk ProductionMilk Production✓ Feed intakeFeed intake✓ Diet FormulationDiet Formulation✓ Feed AnalysisFeed Analysis✓ Feed DigestibilityFeed Digestibility✓ Feeding ManagementFeeding Management✓ Feeding BehaviorFeeding Behavior

Typical ResultsTypical Results

9

10

11

12

13

14

15

16

17

440

460

480

500

520

540

560

580

600

Nov Dec Jan Feb Mar Apr

MUN NI

BestBest

Study on feeding in Study on feeding in Chesapeake Bay WatershedChesapeake Bay Watershed

Surveyed and sampled 450 farms in regionSurveyed and sampled 450 farms in region Used milk analysis and survey results to Used milk analysis and survey results to

predict N intake, N in urine, N in feces, and predict N intake, N in urine, N in feces, and N utilization efficiency.N utilization efficiency.

Jonker, et al., 2002, J. Dairy ScienceJonker, et al., 2002, J. Dairy Science

Effect of milk per cow on N Effect of milk per cow on N utilization efficiencyutilization efficiency

15

20

25

30

35

40

15 20 25 30 35 40

Efficiency of Feed N Utilization (g N in milk and meat per 100 g N in feed)

4% Fat Corrected Milk (kg/d)

Jonker, et al., 2002, J. Jonker, et al., 2002, J. Dairy ScienceDairy Science

Effect of intake N on Effect of intake N on N utilization efficiencyN utilization efficiency

15

20

25

30

35

40

-100 -50 0 50 100 150 200

Efficiency of Feed N Utilization (g N in milk and meat per 100 g N in feed)

N intake – N required (g/d)

Jonker, et al., 2002, Jonker, et al., 2002, J. Dairy ScienceJ. Dairy Science

Cost of Overfeeding ProteinCost of Overfeeding Protein

Farms feeding above N requirements 70.1%

Added feed cost per overfed cow $32.94

Total cost of N overfeeding in

Chesapeake Bay Watershed ($106)$17.86

Jonker, et al., 2002. J. Dairy Sci.Jonker, et al., 2002. J. Dairy Sci.

Environmental Cost of Environmental Cost of Overfeeding ProteinOverfeeding Protein

Excess N excreted per overfed cow

(kg/yr/cow)18.6

Excess N in watershed from overfeeding

(106 kg/yr)10.1

N loss to water from overfeeding N

(106 kg/yr)7.6

Jonker, et al., 2002. J. Dairy Sci.Jonker, et al., 2002. J. Dairy Sci.

Phosphorus BalancePhosphorus Balance

FeedHerdSoil

Forage PUptake = 1.2 T/yrGrain P= 1.4 T/yrMineral P = .7 T/yrMilk P = 1.0 T/yrMeat P = .1 T/yrIntake

Manure P = 2.2 T/yrP Accumulation = 1.0 T/yr

How Does P Excretion How Does P Excretion Change with Diet P Level?Change with Diet P Level?

01020304050607080

lbs P in Feces

0.4 0.45 0.6

Dietary P, % of DM

Survey Results for 450 farms Survey Results for 450 farms in MD, VA, PA, WV & DEin MD, VA, PA, WV & DE

0

20

40

60

80

100

0.31 0.38 0.45

% of Farms

Positive P Balance

Negative P Balance

Dietary P Dietary P

P BalanceP Balance

Dietary P Dietary P

P BalanceP Balance

Dietary P, % of DM

Fecal P IndicatorFecal P Indicator

Dou, et al., 2002Dou, et al., 2002J. Environ. Qual.J. Environ. Qual.

0

2

4

6

8

10

12

14

0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7

Total P

Soluble P

Diet P (g/kg)

Research Trials

Feces vs. DietFeces vs. Diet

y = 1.8875x + 1.0323

R

2

= 0.4292

y = 1.0047x - 0.1853

R

2

= 0.3386

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

2.50 3.50 4.50 5.50 6.50

P in diets (g kg

-1

DM)

P in feces (g kg

-1

DM)

TP in acid digest

Pt in water extract

Dou et al., 2003. J. Dairy Sci.Dou et al., 2003. J. Dairy Sci.

Measured vs. FormulatedMeasured vs. Formulated

2.50

3.00

3.50

4.00

4.50

5.00

5.50

6.00

6.50

2.50 3.00 3.50 4.00 4.50 5.00 5.50 6.00 6.50

P in formulated rations (g kg-1 DM)

P in feed samples (g kg

-1 DM)

Dou et al., 2003. J. Dairy Sci.Dou et al., 2003. J. Dairy Sci.

US Dried Distillers Grain US Dried Distillers Grain (Gg/yr)(Gg/yr)

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

1980 1985 1990 1995 2000 2005

Composition Composition (% of DM)(% of DM)

FeedFeed NELNEL CPCP PP

CornCorn 1.901.90 9.49.4 0.300.30

Soybean MealSoybean Meal 2.092.09 53.853.8 0.700.70

Distillers GrainDistillers Grain 1.871.87 29.729.7 0.830.83

Required Required (45kg/d FCM)(45kg/d FCM) 1.551.55 16.316.3 0.380.38

National Research Council, 2001National Research Council, 2001

Price HistoryPrice History

0

50

100

150

200

250

300

19941995199619971998199920002001200220032004

DDGCornSBM (48%)

$/ton USDA National Agriculture Statistics Service, 2005$/ton USDA National Agriculture Statistics Service, 2005

Feeding ProjectionsFeeding Projections

More ethanol productionMore ethanol production– Higher corn pricesHigher corn prices– Lower distillers grain pricesLower distillers grain prices– Lower soybean meal pricesLower soybean meal prices

More use of distillersMore use of distillersMore overfeeding of CP and PMore overfeeding of CP and P

Chesapeake Bay ProgramChesapeake Bay ProgramDairy: Through feed management, achieve 20% reduction in manure nutrients in one-half the cows by 2015.

2.1 million lb/yr less N2.1 million lb/yr less N

0.27 million lb/yr less P0.27 million lb/yr less P

What reduces N & P ?What reduces N & P ?

Formulating closer to requirementsFormulating closer to requirementsReducing N with amino acidsReducing N with amino acidsSubstitution of low-P feeds Substitution of low-P feeds Improved digestibilityImproved digestibilityOtherOther

NRCS-funded ProgramNRCS-funded Program

Upgrade milk processor labs to enable Upgrade milk processor labs to enable routine, accurate analysis of MUNroutine, accurate analysis of MUN

Quality control of MUN analysesQuality control of MUN analysesEducation to nutritionists and farmersEducation to nutritionists and farmersProvide one-time incentive payments Provide one-time incentive payments

to farmers maintaining low MUNto farmers maintaining low MUN