Effects of Dietary Nitrogen Manipulation on Ammonia Volatilization from Manure from Holstein Heifers

Abstract

Decomposition of livestock manure produces gaseous ammonia. Dietary manipulation is one means to reduce N in manure and ammonia volatilization. The effects of dietary crude protein concentration on N intake, N and urinary urea-N excretion, and ammonia volatilization were measured. Eight Holstein heifers (body weight = 260 to 488 kg) were fed a total mixed ration containing either 9.6 or 11.0% crude protein in a crossover design. Oatlage and concentrate were fed at 77:23 (dry matter basis), and soybean meal was used to alter total dietary crude protein. Seven-day adjustment periods preceded 5-d collection periods. Indwelling urinary catheters were inserted 2 d prior to the collection periods. Daily feces and acidified urine were collected, stirred, and subsampled for total Kjeldahl N, urinary urea N, dry matter, P, K, and ash. Urine collection tubes were split during period 2 to allow for collection of unacidified samples for urea N and total N determinations. Unacidified urine and fecal samples were combined (1:1.3) for collection of volatilized ammonia. Remaining slurries were extracted for total and urea N. Increased dietary crude protein concentration increased N intake, N excretion, urea-N excretion, and N excreted in the urine by the heifers. Dietary manipulation of N intake by reduction of 14.0% (dry matter basis) resulted in a 28.1% decrease in ammonia emission and decreases in the urea N, total N, and percentage N excreted in the urine of 29.6, 19.8, and 7.4%, respectively. Ammonia volatilization was dependent on N quantity and form in the urine.

Ammonia Emission Factors for Open-Lot Dairies: Direct Measurements and Estimation by Nitrogen Intake

“…In vitro experiments incorporated with the metabolism studies established a potential for NH 3 emissions equal to urea-N excretion, which can be estimated by dietary parameters. 10 …”

“…10,20 Briefly, Holstein calves, heifers, and milking cows were confined in crates or tie stalls on the University of California, Davis campus for 8 days during which total feed intake and fecal and urinary outputs were weighed and sampled. Analyses of feed, feces, and urine provided N intake and fecal, urinary, and urea N excretion in g day Ϫ1 .…”

“…Within California, the Southeast Desert, the South Coast (SC), and the San Joaquin Valley (SJV) air basins all exceed the federal standard for suspended particles with aerodynamic diameters Ͻ10 m (PM 10 ). Federal law requires the preparation of State Implementation Plans (SIPs) that describe the actions the regional Air Quality Management Districts will take to bring the regions into compliance with federal standards.…”

“…Ammonium nitrate has been shown to comprise as much as 27% of the total PM 10 concentration in the SJV during the winter, the season in which the SJV district is most likely to exceed the federal PM 10 standard. 1 An understanding of NH 3 sources is essential to determining PM 10 inventories because of the unique role NH 3 plays in the chemistry that controls concentrations of PM. 2 NH 3 emission inventories provide input to atmospheric models necessary for SIP development and implementation.…”

“…8 The dependence of NH 3 emission from dairy cattle housing on the quantity and quality of N ingested by the animals has been observed by many researchers. [10][11][12][13][14][15] Diet modification is a recognized mitigation strategy to control NH 3 emissions. 16 NH 3 emission factors based on onfarm nutrient management have the potential for site IMPLICATIONS NH 3 emission factors are needed by Air Quality Management Districts for development of State Implementation Plans.…”