scholarly journals Using Milk Urea Nitrogen to Predict Nitrogen Excretion and Utilization Efficiency in Lactating Dairy Cows

1998 ◽  
Vol 81 (10) ◽  
pp. 2681-2692 ◽  
Author(s):  
J.S. Jonker ◽  
R.A. Kohn ◽  
R.A. Erdman
Keyword(s):  
Dairy Cows ◽  
Utilization Efficiency ◽  
Nitrogen Excretion ◽  
Urea Nitrogen ◽  
Lactating Dairy Cows ◽  
Milk Urea ◽  
Milk Urea Nitrogen

319 Predicting Urinary Nitrogen Excretion from Milk Urea Nitrogen of Fresh Forage or Total Mixed Ration Fed Dairy Cows: A Meta-analysis

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 171-171
Author(s):  
Matthew R Beck ◽  
Cameron Marshall ◽  
Konagh Garrett ◽  
Andrew P Foote ◽  
Ronaldo Vibart ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Meta Analysis ◽  
Live Weight ◽  
Predictive Ability ◽  
Nitrogen Excretion ◽  
Good Precision ◽  
Urea Nitrogen ◽  
Total Mixed Ration ◽  
Milk Urea ◽  
Milk Urea Nitrogen

Abstract Urine nitrogen excretion (g/d; UN) represent a significant environmental impact for both confinement feeding and pastoral based dairy systems. It is difficult to measure UN directly due to animal handling and labor requirements, especially in forage based production systems. The currently available milk urea nitrogen (MUN) equations have been shown to overestimate UN excretion of grazing dairy cows compared with an equation using urinary creatinine and UN concentration, indicating that diet may alter the relationship between MUN and UN. This potential was explored using data retrieved (treatment means: n = 69 and 27 for fresh forage [FF] and total mixed ration [TMR] fed cattle, respectively) from the literature and new data obtained from dairy cows fed FF (n = 15) in metabolism crates was used to test the new equations. The TMR data from literature was further split into a training set (to develop the model; n = 53) and a test set (to validate the model; n = 16). There was an interaction for diet type (P < 0.01) where UN (g/d) = 0.023 × MUN (mg/dL) × live-weight (kg, LW) for TMR fed cattle, (similar to a pre-established equation); however, UN (g/d) = 0.015 × MUN × LW for FF fed cattle. For FF based equations, the New MUN equation and the creatinine equation showed good precision and accuracy (Lin’s CCC = 0.79 and 0.74, respectively) and adequate predictive ability (RMSEP = 29.8 and 35.9, respectively). The new MUN equation for TMR fed cattle showed excellent accuracy and precision (Lin’s CCC = 0.87) with good predictive ability (RMSEP = 24.3) for UN excretion (observed mean = 216.5 g/d). The new equations generated during this meta-analysis provide promising predictive ability of UN excretion, which can be used for management considerations, future research, and policy making.

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

2001 ◽  
Vol 1 ◽  
pp. 852-859 ◽  
Author(s):  
J.S. Jonker ◽  
R.A. Kohn
Keyword(s):  
Environmental Impact ◽  
Dairy Cattle ◽  
Dairy Cows ◽  
Chesapeake Bay ◽  
Dairy Farms ◽  
Utilization Efficiency ◽  
Urea Nitrogen ◽  
Lactating Dairy Cows ◽  
Milk Urea ◽  
Lactating Dairy Cattle

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.

Milk urea-nitrogen negatively affected first-service breeding success in commercial dairy cows in Prince Edward Island, Canada

2007 ◽  
Vol 82 (1-2) ◽  
pp. 42-50 ◽  
Author(s):  
P. Arunvipas ◽  
J.A. VanLeeuwen ◽  
I.R. Dohoo ◽  
E.R. Leger ◽  
G.P. Keefe ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Breeding Success ◽  
Prince Edward Island ◽  
Urea Nitrogen ◽  
Milk Urea ◽  
Milk Urea Nitrogen

scholarly journals Corn supplementation on milk urea nitrogen content of dairy cows grazing on temperate annual pasture

2020 ◽  
Vol 50 (2) ◽  
Author(s):  
Aline Cristina Dall-Orsoletta ◽  
João Gabriel Rossini Almeida ◽  
Márcia Maria Oziemblowski ◽  
Henrique Mendonça Nunes Ribeiro-Filho
Keyword(s):  
Dairy Cows ◽  
Protein Production ◽  
Milk Protein ◽  
Live Weight ◽  
Corn Silage ◽  
Utilization Efficiency ◽  
Urea Nitrogen ◽  
Plasma Urea ◽  
Lactation Stage ◽  
Milk Urea

ABSTRACT: The excretion of urinary nitrogen (N), one of the most important environmental contaminants from livestock systems, is highly correlated with milk urea N content. The objective of this research was to evaluate the use of different types of corn supplementation on milk urea N in grazing dairy cows. Twelve Holstein × Jersey lactating dairy cows were divided into six uniform groups according to milk production, lactation stage and live weight. Treatments were compared according to a 3 × 3 replicated Latin square experimental design, with three periods of seventeen days (twelve days to adaptation and five to measurements). The experimental treatments were exclusively grazing (G); grazing + supplementation with 4.2 kg DM of corn silage (CS) and grazing + supplementation with 3.2 kg DM of ground corn (GC). The pasture used was annual ryegrass (Lolium multiflorum L.) and white oats (Avena sativa L.). The milk protein production increased 65 g/day in the GC treatment group compared to the G and CS groups. The supplemented dairy cows showed lower milk urea N (-2.8 mg/dL) than unsupplemented cows, but the N utilization efficiency (g N output in milk/ g N intake) did not change between treatments (average = 0.26). Additionally, there was a relationship between milk and plasma urea nitrogen concentrations (R2 = 0.64). In conclusion, for dairy cows grazing annual temperate pastures, corn ground supplementation increased milk protein production and reduced the excretion of milk urea N, whereas corn silage reduced the excretion of milk urea N without affecting milk protein production.

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