P1246990943eJsYP

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Enhancing Nitrogen Efficiency by Lactating Dairy
Cows
Virginia Ishler Nutrient Management
Specialist Dairy Complex Manager vishler_at_psu.edu
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Development of instrumentation to measure ammonia
volatilization from manure Evaluation of
dietary strategies to increase nitrogen
utilization and reduce ammonia emissions from
manure of lactating dairy cattle

• Neil E. Brown
• PhD Defense Seminar
• Dept of Dairy and Animal Science
• The Pennsylvania State University
• Aug. 23. 2007

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Factors affecting ammonia emissions estimates

• Innate manure characteristics
• - conc. of urea in urine
• - manure pH
• - urinefeces
• - moisture
• Environmental factors
• - temperature
• - wind-speed
• Measurement techniques
• - Micrometeorological
• - Manure N balance
• - Direct measurement (flux chambers)

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Carbohydrate fermentability

• Reduction in corn particle size increased ruminal
  degradation of starch (Lykos and Varga, 1995)
• Increase in starch availability in the rumen
  increased microbial protein (Lykos and Varga,
  1995)
• Increased microbial protein increased NH3
  utilization in the rumen
• Increase in rumen fermentable carbohydrates
  tended to increase milk yield and efficiency of
  production
• (Krause et al., 2002)

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• To develop instrumentation
• - to measure NH3 volatilization from manure
• - to evaluate instrumentation using different
  dietary strategies

Note Measurements reflect cool weather
conditions and rations developed to meet the
cows requirement for protein.
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Objectives Expt. 1

• To measure the NH3 emissions from a free-stall
  dairy barn
• To determine the effects of precision feeding
  strategies on NH3 emissions from manure

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Materials and methods

• 120 cows divided into two equal groups in a
  switchback design
• Section A - alfalfa silage based rations
• Section B - grass silage based rations
• Groups balanced for milk production and lactation
  

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Management and sampling

• Animals milked 2 x daily (bST used)
• Milk production, DMI, BW recorded daily
• MUNs and Milk N efficiency
• Milk samples milk fat, protein

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Composition of diets, DM
All diets were formulated for RDP, RUP and MP
using NRC 2001.
CP 16.5, NDF 32
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Production parameters
Forage, P 11
No differences in NH3 volatilization
Power 0.9 to 0.95
Per 60 cows
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Conclusions Expt. 1

• Ammonia emissions not significantly impacted by
  dietary treatment.
• Emissions resulted in 0.11 lb of NH3/cow/day.

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MUNs and Milk N Efficiency

• MUNs
• Represent urea levels of blood and other body
  fluids.
• Good monitor of protein and CHO status.
• Correlated with urinary N excretion
• Ideal range 8 to 12 mg/dl

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MUNs and Milk N Efficiency
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MUNs and Milk N Efficiency

• MUN Milk N Eff
• mg/dl
• Alfalfa fine 11.0 28.1
• Alfalfa coarse 9.5 30.0
• Grass fine 10.5 32.2
• Grass coarse 11.5 30.1

Ammonia Emissions Research Penn State
University
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Conservation Innovation GrantTMR Analysis 52
farms
Protein fractions
MUNs
Drs. Jim Ferguson and Bob Munson University of
PA
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Monocacy Watershed Precision Feeding Project PA
portion
Ishler and Cowan Penn State
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SARE Precision Feeding Project
2007
2008
11 farms averaging 180 cows
Sustainable Agricultural Research and Education
Gene Schurman
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SARE Precision Feeding Project
11 farms averaging 180 cows
Sustainable Agricultural Research and Education
Gene Schurman
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Precision Feeding - Applied
2006 -2007
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Precision Feeding - Applied
2007 -2008
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Are there any questions?