scholarly journals Milk Urea Concentration to the Evaluation of Nitrogen Efficiency Transformation on Dairy Farms

2021 ◽  
Vol 65 (3) ◽  
pp. 30-39
Author(s):  
I. Maskaľová ◽  
V. Vajda
Keyword(s):  
Multiple Regression ◽  
Nitrogen Concentration ◽  
Nutrient Content ◽  
Nitrogen Efficiency ◽  
Regression Equations ◽  
Urea Nitrogen ◽  
Regression Relationship ◽  
Milk Urea ◽  
Nutritional Effects ◽  
Milk Urea Nitrogen

Abstract The aim of this study was to evaluate the effects of nutrition on the milk urea nitrogen (MUN) concentration; on the transformation of N in the farm’s conditions; and there-by allow the milk urea nitrogen concentration to serve as a tool to maximize the protein nutrition and the metabolism of the cows. The relations evaluated by linear or multiple regression confirmed that the highest nutritional effects of the crude protein (CP) on the MUN concentration, which represented a 69.3 % variation in the MUN content. According to the CP content in the total mix ration (TMR) and MUN content (3150 milk samples) under farm conditions, a regression relationship was determined for the estimated of MUN (mg.dl–1) = –13.2 + 0.16 × CP (g.kg–1 dry matter). For multiple regression, the rate of variation expressed by this relationship increased to 72 for nutrient content and 78.3 % for nutrient intake in the TMR. The efficiency of nitrogen utilization (ENU) determined by calculations based on the MUN content according to the regression equations represented a negative correlation (P < 0.0001; R2 = 0.854) with respect to the CP content in the TMR and that the increased CP content by 1 % in the range of 14 to 18 % in the TMR decreased the ENU by 1.48 %. Validation of the models for prediction of nitrogen transformation (ENU) for practical application on the farms determined the best equation, which used the available data from the routine analysis of Breeding services of Slovakia. After taking into consideration of our breeding conditions, it was confirmed that the equation of ENU had taken into account the MUN, in addition to the amount of the milk produced.

scholarly journals Milk Urea Nitrogen Concentration: Heritability and Genetic Correlations with Reproductive Performance and Disease

2005 ◽  
Vol 88 (12) ◽  
pp. 4434-4440 ◽  
Author(s):  
R.G. Mitchell ◽  
G.W. Rogers ◽  
C.D. Dechow ◽  
J.E. Vallimont ◽  
J.B. Cooper ◽  
...  
Keyword(s):  
Reproductive Performance ◽  
Nitrogen Concentration ◽  
Genetic Correlations ◽  
Urea Nitrogen ◽  
Milk Urea ◽  
Milk Urea Nitrogen

Factors affecting the milk urea nitrogen concentration in Chinese Holstein cows

2018 ◽  
Vol 68 (2) ◽  
pp. 193-211 ◽  
Author(s):  
Huimin Zhang ◽  
Mengqi Wang ◽  
Hongrui Jiang ◽  
Yan Cui ◽  
Hailei Xia ◽  
...  
Keyword(s):  
Protein Content ◽  
Nitrogen Concentration ◽  
Dairy Farm ◽  
Urea Nitrogen ◽  
Factors Affecting ◽  
Chinese Holstein ◽  
Chinese Holstein Cows ◽  
Milk Urea ◽  
Positive Correlations ◽  
Milk Urea Nitrogen

AbstractIn order to investigate the factors affecting milk urea nitrogen in Chinese Holstein cows, a large commercial dairy farm participated in a 30-month study. In this study, the mean milk urea nitrogen concentration was 11.75 mg/dl. The milk urea nitrogen reached its maximum value on day 90 of lactation for the first parity and the third or higher parities, but it peaked at the end of lactation for the second parity. The milk urea nitrogen of the first parity was lower than that of other parities. The milk urea nitrogen showed its minimum level in January, and reached its maximum in July. The milk urea nitrogen at the first month of lactation in cows calving in summer was higher than other seasons, while at the fourth month of lactation, the milk urea nitrogen of cows calving in autumn was significantly lower than in cows calving in other seasons. Positive correlations were observed between daily milk yield, net energy for lactation, crude protein and milk urea nitrogen for the first and third parities, but negative correlations were observed in the second parity. The milk urea nitrogen showed significantly positive correlations with fat content, total solid content and daily matter intake for all parities. A negative correlation was observed between milk urea nitrogen and protein content, with the exception of the second parity. For all data, as milk urea nitrogen concentration increased, milk protein content decreased. It has been recommended that milk urea nitrogen concentration should be evaluated in combination with parity, days in milk, season (or month), daily matter intake and dietary nutritional components, in order to improve the management and economic benefits of dairy farm.

scholarly journals 165 Evaluation of Milk Urea Nitrogen Measurement Precision and Accuracy

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 134-134
Author(s):  
Kristan F Reed ◽  
Emma Wood ◽  
David M Barbano ◽  
Matilde Portnoy
Keyword(s):  
Milk Fat ◽  
Fixed Effects ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Random Effect ◽  
Nitrogen Efficiency ◽  
Urea Nitrogen ◽  
Milk Urea ◽  
Precision And Accuracy ◽  
Milk Urea Nitrogen

Abstract High levels of urea in blood, milk and urine have been linked to poor nitrogen efficiency, increased feed costs, poor reproductive performance and increased environmental impacts of dairy farming. Milk urea nitrogen (MUN) is a commonly used metric to manage herd nitrogen efficiency, with current recommendations for MUN to be between 8–14 mg/dL to maintain milk production and reduce nitrogen losses. However, a previous work suggests commercial analysis of MUN with mid-infrared spectroscopy (MIR) may not be precise enough to determine if a milk sample is within the recommended range. Thus, the objective of this study was to evaluate the precision and accuracy of milk testing lab MUN measurements. Four sets of bulk tank samples were sent to 3 commercial labs and one research lab for analysis by MIR. Samples were sent to commercial labs in duplicate and MUN was also assessed through an enzymatic assay. The Euclidean distance (ED) was calculated as a combined metric of precision and accuracy. The ED was not different between labs and ranged from 0.81–1.27. Repeatability (sr) and reproducibility (sR) were estimated for commercial labs and ranged from (0.297–0.469) and (0.555–0.791) respectively. Differences between individual sample MIR and enzymatic MUN were regressed on the centered enzymatic MUN in a linear mixed model that included a random effect of lab and fixed effects for milk protein and milk fat. Regression results indicate MIR analysis over-predicts MUN at low MUN concentrations and under predicts MUN at high MUN concentrations. Results suggest MIR analysis of MUN is more accurate around milk MUN, protein, and fat concentrations of ~13 mg/dl, 3.4% protein, and 4.2% fat. Further, the combined residual error and random effect of lab suggest the standard error of an MUN MIR measurement is ±1.8.

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