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Using Milk Urea Nitrogen to Evaluate Diet Formulation and Environmental Impact on Dairy Farms

Reducing nitrogen (N) excretion by dairy cattle is the most effective means to reduce N losses (runoff, volatilization, and leaching) from dairy farms. The objectives of this review are to examine the use of milk urea nitrogen (MUN) to measure N excretion and utilization efficiency in lactating dair...

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Detalles Bibliográficos
Autores principales: Jonker, J.S., Kohn, R.A.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: TheScientificWorldJOURNAL 2001
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6084535/
https://www.ncbi.nlm.nih.gov/pubmed/12805886
http://dx.doi.org/10.1100/tsw.2001.265
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author Jonker, J.S.
Kohn, R.A.
author_facet Jonker, J.S.
Kohn, R.A.
author_sort Jonker, J.S.
collection PubMed
description Reducing nitrogen (N) excretion by dairy cattle is the most effective means to reduce N losses (runoff, volatilization, and leaching) from dairy farms. The objectives of this review are to examine the use of milk urea nitrogen (MUN) to measure N excretion and utilization efficiency in lactating dairy cows and to examine impacts of overfeeding N to dairy cows in the Chesapeake Bay drainage basin. A mathematical model was developed and evaluated with an independent literature data set to integrate MUN and milk composition to predict urinary and fecal excretion, intake, and utilization efficiency for N in lactating dairy cows. This model was subsequently used to develop target MUN concentrations for lactating dairy cattle fed according to National Research Council (NRC) recommendations. Target values calculated in this manner were 8 to 14 mg/dl for a typical lactation and were most sensitive to change in milk production and crude protein intake. Routine use of MUN to monitor dairy cattle diets was introduced to dairy farms (n = 1156) in the Chesapeake Bay watershed. Participating farmers (n = 454) were provided with the results of their MUN analyses and interpretive information monthly for a period of 6 months. The average MUN across all farms in the study increased in the spring, but the increase was 0.52 mg/dl lower for farmers receiving MUN results compared to those who did not participate in the program. This change indicated that participating farmers reduced N feeding compared to nonparticipants. Average efficiency of feed N utilization (N in milk / N in feed x 100) was 24.5% (SD = 4.5). On average, farmers fed 6.6% more N than recommended by the NRC, resulting in a 16% increase in urinary N and a 2.7% increase in fecal N compared to feeding to requirement. N loading to the Chesapeake Bay from overfeeding protein to lactating dairy cattle was estimated to be 7.6 million kg/year. MUN is a useful tool to measure diet adequacy and environmental impact from dairy farms.
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spelling pubmed-60845352018-08-26 Using Milk Urea Nitrogen to Evaluate Diet Formulation and Environmental Impact on Dairy Farms Jonker, J.S. Kohn, R.A. ScientificWorldJournal Research Article Reducing nitrogen (N) excretion by dairy cattle is the most effective means to reduce N losses (runoff, volatilization, and leaching) from dairy farms. The objectives of this review are to examine the use of milk urea nitrogen (MUN) to measure N excretion and utilization efficiency in lactating dairy cows and to examine impacts of overfeeding N to dairy cows in the Chesapeake Bay drainage basin. A mathematical model was developed and evaluated with an independent literature data set to integrate MUN and milk composition to predict urinary and fecal excretion, intake, and utilization efficiency for N in lactating dairy cows. This model was subsequently used to develop target MUN concentrations for lactating dairy cattle fed according to National Research Council (NRC) recommendations. Target values calculated in this manner were 8 to 14 mg/dl for a typical lactation and were most sensitive to change in milk production and crude protein intake. Routine use of MUN to monitor dairy cattle diets was introduced to dairy farms (n = 1156) in the Chesapeake Bay watershed. Participating farmers (n = 454) were provided with the results of their MUN analyses and interpretive information monthly for a period of 6 months. The average MUN across all farms in the study increased in the spring, but the increase was 0.52 mg/dl lower for farmers receiving MUN results compared to those who did not participate in the program. This change indicated that participating farmers reduced N feeding compared to nonparticipants. Average efficiency of feed N utilization (N in milk / N in feed x 100) was 24.5% (SD = 4.5). On average, farmers fed 6.6% more N than recommended by the NRC, resulting in a 16% increase in urinary N and a 2.7% increase in fecal N compared to feeding to requirement. N loading to the Chesapeake Bay from overfeeding protein to lactating dairy cattle was estimated to be 7.6 million kg/year. MUN is a useful tool to measure diet adequacy and environmental impact from dairy farms. TheScientificWorldJOURNAL 2001-10-18 /pmc/articles/PMC6084535/ /pubmed/12805886 http://dx.doi.org/10.1100/tsw.2001.265 Text en Copyright © 2001 J.S. Jonker and R.A. Kohn. https://creativecommons.org/licenses/by/3.0/ This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research Article
Jonker, J.S.
Kohn, R.A.
Using Milk Urea Nitrogen to Evaluate Diet Formulation and Environmental Impact on Dairy Farms
title Using Milk Urea Nitrogen to Evaluate Diet Formulation and Environmental Impact on Dairy Farms
title_full Using Milk Urea Nitrogen to Evaluate Diet Formulation and Environmental Impact on Dairy Farms
title_fullStr Using Milk Urea Nitrogen to Evaluate Diet Formulation and Environmental Impact on Dairy Farms
title_full_unstemmed Using Milk Urea Nitrogen to Evaluate Diet Formulation and Environmental Impact on Dairy Farms
title_short Using Milk Urea Nitrogen to Evaluate Diet Formulation and Environmental Impact on Dairy Farms
title_sort using milk urea nitrogen to evaluate diet formulation and environmental impact on dairy farms
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6084535/
https://www.ncbi.nlm.nih.gov/pubmed/12805886
http://dx.doi.org/10.1100/tsw.2001.265
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