Erickson, Peter S.

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University of New HampshireUniversity of New Hampshire Scholars' RepositoryFaculty Publications12-6-2017Using Milk Urea Nitrogen to Calculate Urine andUrinary Nitrogen OutputPeter S. EricksonFollow this and additional works at: https://scholars.unh.edu/faculty_pubs7/10/2019 Using Milk Urea Nitrogen to Calculate Urine and Urinary Nitrogen Output | UNH Extensionhttps://extension.unh.edu/blog/using-milk-urea-nitrogen-calculate-urine-and-urinary-nitrogen-output 1/6Search  Search this SiteDonateProfessional Development and TrainingUNH HomeTopicsLocationsBlogEventsResourcesAboutUsing Milk Urea Nitrogen to Calculate Urine andUrinary Nitrogen OutputDecember 6, 2017Blog > Using Milk Urea Nitrogen to Calculate Urine and Urinary Nitrogen Output7/10/2019 Using Milk Urea Nitrogen to Calculate Urine and Urinary Nitrogen Output | UNH Extensionhttps://extension.unh.edu/blog/using-milk-urea-nitrogen-calculate-urine-and-urinary-nitrogen-output 2/6Using Milk Urea Nitrogen to Calculate Urine and Urinary NitrogenOutput1) Why is this important?The amount of urine produced by dairy cows affects total manure excretion because urine excretion accounts forabout 1/3 of the total manure excretion on a weight basis (NRC, 2001).  With the development of manurestorage facilities knowing how much urine will be produced and how large a storage facility will be needed.2) Development of the equation.Researchers at several institutions evaluated models to predict urine output (Nennich et al., 2006).  Earlyequations linked urine output to the intakes of sodium and potassium along with nitrogen (crude protein of thediet).  Urinary excretion is due to regulation of the body’s sodium and potassium balance.  A challenge for usingthese equations was that the intake of these components was required.  While it is possible to know how much ofeach is fed, it is more difficult to know how much is consumed without measuring the content of the feedrefusals. In the late 1990’s and early 2000’s several equations were developed including using body weight,crude protein intake, and dry matter intake along with dietary cation anion difference.  Dairy producers haveaccess to MUN and can accurately calculate both urinary excretion and urinary nitrogen excretion on a per cowbasis and then convert it to a pen or herd basis.3) Implementation of the equationEMAIL FACEBOOK LINKEDIN TWITTER GOOGLE+ PINTEREST7/10/2019 Using Milk Urea Nitrogen to Calculate Urine and Urinary Nitrogen Output | UNH Extensionhttps://extension.unh.edu/blog/using-milk-urea-nitrogen-calculate-urine-and-urinary-nitrogen-output 3/6We can estimate urine excretion with the following formula:Based on the equation reported by Nennich et al. (2006) urine excretion in kg/day can be estimated using thefollowing equation = (MUN × 0.563) + 17.1For instance- let’s say your MUN was 10 mg/dL (considered normal)Urine excretion = 10 × 0.563 + 17.1 = 22.7 kg/day, 1 kg =1 liter22.7 liters is about 50 pounds of urine (1 liter = 2.205 pounds). For a herd of 200 lactating cows this equals10,000 pounds of urine per day.  To convert to gallons (1 gal = 8.35 pounds) or about 1,200 gallons/day. What happens if your MUN is 16 mg/dL  (considered high)?Urine excretion = (16 × 0.563) +17.1 = 26.1 kg (liters) per cow per day. This is equivalent to 5,220 liters (or 1378 gallons) per day for our herd of 200 cows.  This results in  178 extragallons of urine per day.4) How much nitrogen will these cows excrete in their urine per day?University of Maryland researchers (Kohn et al. 2002) developed an equation which estimates the amount ofnitrogen excreted in urine by a cow each day. In this equation urinary N excretion in grams per day = (15.1 ×MUN) + 27.8.  For example, using the example above with 10 mg/dL MUN urinary N excretion will equal:  15.1 × 10 =151 + 27.8 =178.8 g/day. With 454 g/pound that amounts to 0.394 pounds of N per cow per day.  For a 200 cow dairy this will translate toalmost 79 pounds of N per day.What if the MUN = 16 mg/dL.(15.1 × 16) + 27.8 = 269.4 g/day or 0.593 pounds of N per day.  For a 200 cow dairy this translates to 118.7pounds of N5) What about other breeds?The above equation is for Holsteins, but what if you have a different breed?   You can still estimate urinarynitrogen if you know the body weight. This equation will work for all breeds including Holsteins (Kauffman andSt. Pierre, 2001).Urinary nitrogen (grams/d) = 0.0259 × Body weight in kilograms × MUN.To convert from pounds to kg = pounds /2.205 = kg. For instance, a 1000 pound cow weighs 454 kg and using aMUN of 16 mg/dLUrinary Nitrogen = 0.0259 × 454 × 16 = 187.9 g/day of NConclusionThese equations can help dairy producers calculate the size of storage facilities needed and determine theamount of nitrogen produced.References7/10/2019 Using Milk Urea Nitrogen to Calculate Urine and Urinary Nitrogen Output | UNH Extensionhttps://extension.unh.edu/blog/using-milk-urea-nitrogen-calculate-urine-and-urinary-nitrogen-output 4/6Kauffman, A.J. and N.R. St. Pierre. 2001. The relationship of milk urea nitrogen to urine nitrogen excretion inHolstein and Jersey cows. J. Dairy Sci. 84:2284-2294.Kohn, R.A., K.F. Kalscheur, and E. Russek-Cohen. 2002. Evaluation of models to estimate urinary nitrogen andexpected milk urea nitrogen. J. Dairy Sci. 85:227-233.Nennich et al., 2006. Prediction and evaluation of urine and urinary nitrogen and mineral excretion from dairycattle. J. Dairy Sci. 89:353-364.NRC. 2001. Nutrient Requirements of Dairy Cattle. 7th Rev. Ed. Natl. Acad. Sci. Washington, DC.Related pages:Agriculture & HorticultureDairy, Livestock & Forage CropsDairy Production & ManagementAuthor(s)PeterEricksonDairy Production State Specialist603-862-1909peter.erickson@unh.eduYou may also like7/10/2019 Using Milk Urea Nitrogen to Calculate Urine and Urinary Nitrogen Output | UNH Extensionhttps://extension.unh.edu/blog/using-milk-urea-nitrogen-calculate-urine-and-urinary-nitrogen-output 5/6August 6, 2018Growing Farms, Growing CommunitiesWhen Emma Downing ’16 opened Blue Heron Farm in New Boston two...Read MoreAugust 24, 2018In the Weeds with Elaina EnzienUNH Extension staff are in the field every day, working with...Read MoreMarch 2, 2018Losing your s***? Manure nitrogen losses with no-tillFor years, crop advisors – myself included – encouraged farms to...7/10/2019 Using Milk Urea Nitrogen to Calculate Urine and Urinary Nitrogen Output | UNH Extensionhttps://extension.unh.edu/blog/using-milk-urea-nitrogen-calculate-urine-and-urinary-nitrogen-output 6/6Read MoreContact UsUniversity of New Hampshire Cooperative ExtensionTaylor Hall, 59 College Road, Durham, NH Directionsphone: (603) 862-1520  Hours: M-F, 7 a.m.- 5 p.m.Quick LinksCivil Rights StatementIntranet501(c)(3) statusCopyright © 2019The University of New HampshireDurham, NH 03824TTY Users: 7-1-1 or 800-735-2964 (Relay NH)USNH Privacy PoliciesUSNH Terms of UseADA Acknowledgement

Using Milk Urea Nitrogen to Calculate Urine and Urinary Nitrogen Output

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Using Milk Urea Nitrogen to Calculate Urine and Urinary Nitrogen Output

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