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