Importance and factors affecting milk urea nitrogen estimation in dairy cows.
Abstract: Milk urea nitrogen can be a practical indicator of the protein utilization of lactating cows in dairy cattle nutrition programs. Monitoring MUN offers the potential to evaluate the protein concentration in lactating cow rations and reduce farm expenses. The objectives of this study were to describe the factors that affecting milk urea concentrations in dairy cow in the Egyptian commercial dairy herds. Such factors include nutritional management, milk production, parity and lactation stages as managemental variables besides, udder health status and mastitis microbial pathogens and some milk parameters as Fat %, Protein %, Lactose %, SCC and pH as cow factors and finally preservation of milk samples by freezing as sampling factors. The study proved a positive linear correlation between MUN and feeding status and milk production in dairy cows. Since in high producer cows that given good feedstuff had MUN concentration 12.84 ± 1.02 mg/dl while it was 9.52 ± 0.23 mg/dl in low producer cows with poor feeding system. Milk urea was generally lower in primiparous cows (11.84 ± 1.02 mg/dl) than in older dairy cows in 2-4 lactation seasons or more than 4 seasons (14.52 ± 0.23 and 13.75 ± 0.71 mg/dl, respectively) and during the early lactation stage (10.98 ± 0.87 mg/dl). MUN concentrations were significantly influenced with the presence of bacterial species in bovine milk samples (P < 0.01) in compared them with milk samples without bacterial growth. Moreover, storage of milk samples at deep freezing or refrigerating did not influence the MUN up to 2 weeks and keep the reproducibility of MUN constant. The relationship between MUN and milk components showed that MUN was negatively associated with the percentages of milk fat % and SCC; however, we observed a positive relationship between MUN and milk protein percentage by using a linear regression model. In conclusion, Maintaining and monitoring MUN in the dairy herds provides an opportunity to formulate the dairy protein constituency that optimize nitrogen utilization for milk production and avoid possible negative effects on herd productivity. MUN varied by parity, stage of lactations, milk production. Controlling of these variables must put in consideration as potential confounders when exploring the relationship between MUN and nutritional management or measures of performance such as production. Freezing or even refrigerating of the milk samples is beneficial in situations such as field trials when there may be long period between the time of milk sampling and MUN analysis
Publication year 2012
Pages 245-258
Organization Name
Country Egypt
serial title مجلة الجمعيه المصريه الطبيه البيطريه
Volume 72 . 2
Author(s) from ARC
Publication Type Journal
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