Rick KohnRick KohnLouise LawrenceLouise Lawrence

A program to improve dairy herd A program to improve dairy herd nutrition using milk urea nitrogennutrition using milk urea nitrogen

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Department of AgricultureDepartment of Agriculture

OverviewOverview

BackgroundBackground

Project overviewProject overview

Experience so farExperience so far

Milk Urea NitrogenMilk Urea Nitrogen

Nitrogen MetabolismNitrogen Metabolism

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

ImplicationsImplications

Milk urea is proportional to blood urea.Milk urea is proportional to blood urea.

Milk urea is proportional to amount of Milk urea is proportional to amount of excess amino acids and ammonia excess amino acids and ammonia absorbed.absorbed.

High milk urea indicates that more than High milk urea indicates that more than enough N was absorbed into the body.enough N was absorbed into the body.

Low milk urea indicates that too little N was Low milk urea indicates that too little N was absorbed.absorbed.

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)

Uri

ne N

Exc

retio

n (g

/d)

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

Nutrient Balance in a CowNutrient Balance in a Cow

IntakeIntake

MilkMilk

WasteWaste

Target MUNTarget MUN

02

468

10121416

1820

0 100 200 300DIM

MU

N (

mg

/dl)

12,000-kg10,000-kg8,000-kg

MUN Target Concentrations for MUN Target Concentrations for Holstein CowsHolstein Cows

Target vs. Observed MUNTarget vs. Observed MUN

02468

101214161820

0 100 200 300DIM

MU

N (

mg

/dl)

ObservedTarget

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

Lab DifferencesLab Differences

Foss 4000 NIRS is not as repeatable as Foss 4000 NIRS is not as repeatable as wet chemistry or Foss 6000.wet chemistry or Foss 6000.

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

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)

MU

N (m

g/dl

)

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

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

Change in MUN (mg/dl) and nitrogen intake (g/d) reported on a farm.

MUN NIM

ilk u

rea

nitr

ogen

(M

UN

, mg/

dl)

Nitrogen Intake (g/d)

Month

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

Effi

cien

cy o

f F

eed

N U

tiliz

atio

n (g

N in

milk

and

mea

t pe

r 10

0 g

N in

fee

d)

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

Effi

cien

cy o

f F

eed

N U

tiliz

atio

n (g

N in

milk

and

mea

t pe

r 10

0 g

N in

fee

d)

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.

Project GoalProject Goal

Institutionalize MUN analysis in Institutionalize MUN analysis in Maryland and Virginia (and the Maryland and Virginia (and the country).country).

ParticipantsParticipants

University of MarylandUniversity of Maryland– Coordination, Quality Control, Teaching, Trouble Shooting, Coordination, Quality Control, Teaching, Trouble Shooting,

EvaluationEvaluation Maryland Department of AgricultureMaryland Department of Agriculture

– CoordinationCoordination Virginia TechVirginia Tech

– Teaching, Trouble ShootingTeaching, Trouble Shooting Milk CooperativesMilk Cooperatives

– Information diseminationInformation disemination Milk Analysis LaboratoriesMilk Analysis Laboratories

– AnalysisAnalysis

Barriers to Use of MUNBarriers to Use of MUN

Inconvenience of sampling and Inconvenience of sampling and analysisanalysis

Inconsistent analysis resultsInconsistent analysis resultsLack of understanding of MUN resultsLack of understanding of MUN resultsLack of incentive to decrease MUNLack of incentive to decrease MUN

MethodsMethods

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

IncentivesIncentives

Nominal payment ($100-150) for MUN Nominal payment ($100-150) for MUN below target (11 mg/dl) for 3 monthsbelow target (11 mg/dl) for 3 months

Publication (with permission) of the Publication (with permission) of the names of the 10 top producers per names of the 10 top producers per county for high milk yield with low county for high milk yield with low MUN.MUN.

Experience So FarExperience So Far

Presentations and InterviewsPresentations and Interviews– Agents, Farmers, Nutritionists, MASCDAgents, Farmers, Nutritionists, MASCD

Contracts with co-ops and labsContracts with co-ops and labsLaboratory upgradesLaboratory upgrades