The objectives of this study were to describe the relationships between milk urea concentrations and nutritional management, production, and economic variables in commercial dairy herds. Dairy Herd Improvement (DHI) test-day milk urea data, production data, and information on ration nutrient composition and feeding management programs were collected over a 13-mo period from 53 commercial Ontari...

protein nutritional status of dairy cows. Milk urea nitrogen reflects the amount of urea found in milk and these values are closely correlated with the concentration of urea found in the blood. MUN values should not be used by themselves when evaluation a herd’s feeding program but can be used in conjunction with evaluating milk production records, feeding management practices, and dry matter, ...

BACKGROUND The in vivo quality of milk protein fractions has seldom been studied in humans. OBJECTIVE Our objective was to compare the postprandial utilization of dietary nitrogen from 3 [(15)N]-labeled milk products: micellar caseins (MC), milk soluble protein isolate (MSPI), and total milk protein (TMP). DESIGN The macronutrient intakes of 23 healthy volunteers were standardized for 1 wk,...

It has been well documented that a negative relationship exists between blood, plasma, or milk urea nitrogen and fertility in dairy cattle, with increased concentrations of plasma urea nitrogen (PUN; > 19 mg/dL) and milk urea nitrogen (MUN; > 15.4 mg/dL) being associated with suppressed fertility. Although this relationship is not fully understood, likely contributing factors have been suggeste...

Our first objective was to redesign a modified 14-sample milk calibration sample set obtain well-distributed range of urea nitrogen (MUN) concentrations while maintaining orthogonality with variation in fat, protein, and lactose concentration. second determine the within- between-laboratory enzymatic spectrophotometric method on samples degree uncertainty MUN reference values, then use evaluate...

Dietary protein intake is the most important factor determining milk production, milk composition, milk nitrogen efficiency, urinary nitrogen losses, urea content in milk and consequently, ammonia emissions from dairy cow manure. According to the nutrition requirements two main protein sources are available for cows: rumen degradable protein, provided to the animal through ruminally synthesized...

At the 3rd Annual Ruminant Nutrition Symposium (Hammond, 1992), I reviewed the use of blood urea nitrogen (BUN) concentration for monitoring protein status in beef cattle, and discussed the potential for using milk urea nitrogen (MUN) as a noninvasive tool for monitoring protein status in dairy cattle. The purpose of this discussion is to review the basic concepts involved in urea nitrogen as a...

The objective of this review is to describe recent research findings related to the use of milk or blood urea nitrogen to identify inefficiencies in protein nutrition and estimate nitrogen excretion. A mathematical model was developed to integrate milk urea nitrogen (MUN) and milk composition to predict urinary and fecal excretion, intake, and utilization efficiency for nitrogen in lactating da...

This study was conducted to investigate the effects of different levels of peptide supplementation on rumen fermentation pattern, digestibility and microbial protein synthesis. Three rumen-cannulated Holstein dairy cows were used in a 3 × 3 Latin square experiment within 21 days period. The ruminal infusion of sodium caseinate (CN) was 0 (control), 50 and 100 g/d. Dry matter intake, milk yield ...

Nitrogen compounds like urea and melamine are known to be commonly used for milk adulteration resulting in undesired intoxication; a well-known example is the Chinese episode occurred in 2008. The development of a rapid, reliable and economic test is of relevance in order to improve adulterated milk identification. Cyclic voltammetry studies using an Au working electrode were performed on adult...