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Fact Sheet No. 1.631C Livestock Ser ies|Management

Colorado State University

Extension. 12/12.

www.ext.colostate.edu

by S.G. Lupis, K.J. Galles, J.M. Ham, E. Westover, J.J. Stratton, J. Wagner, T. Engle, and J.G. Davis*

Cattle eeding operations have beenidentied as a potential source o ammoniaemissions into the atmosphere. Urea nitrogenin resh urine and eces is deposited on thepen surace where it is quickly broken downand volatilized into the air as ammonia.Ammonia is especially o concern alongColorados Front Range, where upslopeconditions occasionally occur with easterly

winds transporting ammonia rom theEastern Plains to the alpine areas o theRocky Mountains, including Rocky MountainNational Park (RMNP). Ammonia can thenbe scavenged rom the air by precipitationand deposited on the soil surace in pristinehigh-elevation environments where excessnitrogen (N) can negatively impact ragileecosystems. While studies have shown thereare many sources contributing to nitrogendeposition in RMNP (e.g., urban settings,transport rom other states), every eortshould be made to minimize the impact

o livestock. One o the most promisingstrategies or reducing ammonia emissionsrom eedlots is reducing the amount oexcreted nitrogen on the pen surace bymodiying livestock diets.

What Goes in MustCome Out

O the nitrogen ed to bee cattle (oen asprotein), only about 12 to 15% is retained bythe animal. Te rest is excreted onto the pensurace. It is less ecientand costs morewhen bee cattle are ed more nitrogen than

Quick Facts

Only 12-15% of the nitrogen

fed to beef cattle as crude

protein is retained; the rest

is excreted onto the pen

surface.

Reducing crude protein in the

diet can reduce nitrogen lostthrough beef cattle urine and

feces.

Reducing nitrogen lost by

adjusting diet ultimately

can reduced the amount of

nitrogen/ammonia lost to the

atmosphere.

On Colorados Front Range,

nishingbeefcattleon

a reduced-nitrogen diet

during the spring andsummer would likely reduce

environmental impacts as well

as producer costs.

More research needs to be

conducted to assess affects

on cattle performance and

health in a commercial feedlot

setting.

*S.G. Lupis, Institute for Livestock and the Environment,

coordinator; K.J. Galles, Colorado State University,

graduate student, soil and crop sciences; J.M. Ham,

professor, soil and crop sciences; E. Westover, graduate

student, animal sciences; J.J. Stratton, graduate student,

chemistry; J. Wagner, professor, animal sciences;

T. Engle, professor, animal sciences; J.G. Davis,

professor, soil and crop sciences. 12/12

Best Management Practices forReducing Ammonia Emissions:Beef Cattle Nutrition

they need or optimal perormance. Feedingnitrogen in excess o what an animal needsdoesnt increase perormance, so it ends upincreasing eed costs without increasingprots. Tereore, by eeding bee cattle tomeet, but not exceed, requirements or crudeprotein, nitrogen excretion and subsequentemissions will be reduced.

Reducing crude protein in the diet can

reduce nitrogen lost through bee cattle urineand eces. In one study, eeding 11.5% crudeprotein reduced nitrogen loss by 60-200%compared to a diet o 13% crude protein. Inanother study, dietary nitrogen inputs werereduced by 10-20% and resulted in a 15-33%reduction in nitrogen loss. Te notion thatwhat goes in must come out works bothways. For example, a exas study increasedeed nitrogen 15-26% and saw an increase inammonia lost to the atmosphere o 10-64%.

Reducing nitrogen excreted by adjustingdiet ultimately can reduce the amount

o ammonia lost to the atmosphere. Inexas, bee cattle ed a diet with less crudeprotein (11.5%) had 25% less nitrogen lostto volatilization with no impact on animalperormance. A recent study by ColoradoState University scientists comparedemissions between bee cattle nished ondiets with 13.5% and 11.62% crude protein. A21-40% reduction in emissions was observedin the low-nitrogen diet group. However,more research is needed to validate theseresults at commercial scales in dierentenvironments to determine i reductions in

ammonia can be sustained with lower proteindiets without aecting rate o gain, eedeciency, and health.

Overall, these studies suggest thatreducing the crude protein in bee cattle dietscan reduce emissions. In addition, it reducesthe cost o eeding more crude protein thannecessary to maintain animal perormance.On Colorados Front Rangewhere nitrogentransport to sensitive alpine environmentsprimarily happens in the spring and

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summernishing bee cattle on areduced-nitrogen diet during these periodscould both reduce environmental impactsand producer costs; however, impacts oncattle perormance and health need to beinvestigated urther. Some studies haveshown that lower protein diets (11 to 12%)can decrease rate o gain.

ReferencesCole, N.A., R. N. Clark, R. W. odd, C. R.

Richardson, A. Gueye, L. W. Greene,and K. McBride. 2005. Infuence odietary crude protein concentration andsource on potential ammonia emissionsrom bee cattle manure. Journal oAnimal Science 83:722-731.

Cole, N. A., P. J. Deoor, M. L. Galyean, G.C. Du, and J. F. Gleghorn. 2006. Eectso phase-eeding o crude protein onperormance, carcass characteristics,

serum urea nitrogen concentrations,and manure nitrogen o nishingbee steers. Journal o Animal Science84:3421-3432.

Erickson. G. E., . J. Klopenstein, and C.. Milton. 2000. Dietary protein eectson nitrogen excretion and volatilizationrom open-dirt eedlots, in J. A. Moore(Ed.), 8th International Symposiumon Animal Agricultural and FoodProcessing Wastes, ASAE Publications,Des Moines, IA. pp. 297-304.

Galles, K., J. Ham, E. Westover, J. Stratton,

J. Wagner, . Engle, and .C. Bryant.2011. Infuence o reduced N dietson ammonia emissions rom cattleeedlot pens. Atmosphere. 2: 655-670.Open Access: www.mdpi.com/journal/atmosphere.

Kissinger, W. F., R. K. Koelsch, G. E.Erickson, and . J. Klopenstein. 2007.Characteristics o manure harvestedrom bee cattle eedlots. AppliedEngineering in Agriculture 23:357-365.

Malm et al. 2009. Romans: RockyMountain Atmospheric Nitrogen and

Sulur Study. National Park Service.ISSN 0737-5352-84. www.nature.nps.gov/air/Studies/romans.cm.

Reynolds, C. K. and N. B. Kristen. 2008.Nitrogen recycling through the gut andthe nitrogen economy o ruminants:An asynchronous symbiosis. Journal oAnimal Sciences 86:E293-305.

Further Reading

Colorado State University Extension

fact sheet: 1.631 Best Management

Practices for Reducing Ammonia

Emissions

Colorado State University, U.S. Department of Agriculture and Colorado counties cooperating. CSU Extension

programs are available to all without discrimination. No endorsement of products mentioned is intended nor is

criticism implied of products not mentioned.

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