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| Niu, M; Appuhamy, J.A.D.R.N; Leytem, A.B.; Dungan, R.S.; Kebreab, Ermias. |
| The study aimed to examine, simultaneously, the effects of changing dietary forage and crude protein (CP) contents on methane (CH4) emissions and nitrogen (N) excretion from lactating dairy cows. Twelve post-peak lactating Holstein cows were randomly assigned to 4 treatments from a 2×2 factorial arrangement of two dietary forage levels [37.4% (LF) vs. 53.3% (HF) of DM] and two dietary CP levels [15.2% (LP) vs. 18.5% (HP) of DM] in a 4×4 Latin square design with four 18 d periods. Alfalfa hay was the sole source of dietary forage. Cows were fed and milked twice daily. During the first 14 d, cows were housed in a free-stall barn, where enteric CH4 emissions were measured using the GreenFeed system from d 8 to 14 in each period. Cows were then moved to... |
| Tipo: Article |
Palavras-chave: Air Emissions; Animal Production; Feed preference; Animal. |
| Ano: 2016 |
URL: http://eprints.nwisrl.ars.usda.gov/1618/1/1575.pdf |
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| Leytem, A.B.; Dungan, R.S.; Bjorneberg, D.L.; Koehn, A.C.. |
| Concentrated dairy operations emit trace gases such as ammonia (NH3), methane (CH4), and nitrous oxide (N2O) to the atmosphere. The implementation of air quality regulations in livestock-producing states increases the need for accurate on-farm determination of emission rates. The objective of this study was to determine the emission rates of NH3, CH4, and N2O from the open-freestall and wastewater pond source areas on a commercial dairy located in southern Idaho. Gas concentrations and wind statistics were measured each month and used with an inverse dispersion model to calculate emission rates. Average emissions per cow per day from the open-freestall source area were 0.10 kg NH3 and 0.47 kg CH4. Average emissions from the wastewater ponds (g m-2 d-1)... |
| Tipo: Article |
Palavras-chave: Air Emissions; Animal Production; Manure Management. |
| Ano: 2013 |
URL: http://eprints.nwisrl.ars.usda.gov/1501/1/1464.pdf |
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| Bougouin, Adeline; Leytem, A.B.; Dijkstra, Jan; Dungan, R.S.; Kebreab, Ermias. |
| Nitrogen (N) excreted in urine by dairy cows can be potentially transformed to ammonia (NH3) and emitted to the atmosphere. Dairy production contributes to NH3 emission, which can create human respiratory problems and odor issues, reduces manure quality, and is an indirect source of nitrous oxide (N2O). The objective of this study was to (i) investigate environmental factors and measurement method that influence NH3 from dairy housing, and (ii) identify key explanatory variables in the prediction of NH3 emissions from dairy barns using a meta-analytical approach. Data from 25 studies were used for the preliminary analysis and data from 10 studies reporting 87 treatment means were used for the meta-analysis. Season, flooring type, manure handling and... |
| Tipo: Article |
Palavras-chave: Air Emissions; Animal Production; Animal health; Manure. |
| Ano: 2016 |
URL: http://eprints.nwisrl.ars.usda.gov/1624/1/1581.pdf |
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