Effect of rumen-degradable protein balance and forage type on bulk milk urea concentration and emission of ammonia from dairy cow houses
| Autor: | G. van Duinkerken, G. André, M.C.J. Smits, L.B.J. Šebek, G.J. Monteny |
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| Rok vydání: | 2005 |
| Předmět: |
goats
Rumen Silage Animal feed AFSG Agrisystems & Environment Forage Research Institute for Animal Husbandry Agrotechnology and Food Sciences Biology Urine chemistry.chemical_compound Random Allocation Animal science Fodder blood Ammonia Genetics Animals Urea nonprotein nitrogen Dairy farming Dairy cattle Praktijkonderzoek Veehouderij Dose-Response Relationship Drug Temperature food and beverages prediction Agrotechnologie en Levensmiddelentechnologie Animal Feed Housing Animal urine feed characteristics nutrition Milk Agronomy chemistry WIAS Regression Analysis Animal Science and Zoology Cattle Environmental Pollutants Female Dietary Proteins Barn (unit) Food Science |
| Zdroj: | Journal of Dairy Science 88 (2005) 3 Journal of Dairy Science, 88(3), 1099-1112 |
| ISSN: | 0022-0302 |
| Popis: | As the Dutch government and dairy farming sector have given priority to reducing ammonia emission, the effect of diet on the ammonia emission from dairy cow barns was studied. In addition, the usefulness of milk urea content as an indicator of emission reduction was evaluated. An experiment was carried out with a herd of 55 to 57 Holstein-Friesian dairy cows housed in a naturally ventilated barn with cubicles and a slatted floor. The experiment was designed as a 3 x 3 factorial trial and repeated 3 times. During the experiment, cows were confined to the barn (no grazing) and were fed ensiled forages and additional concentrates. The default forage was grass silage. The nutritional experimental factors were: (1) rumen-degradable protein balance of the ration for lactating cows with 3 levels (0, 500, and 1000 g/cow per d), and (2) proportion of corn silage in the forage ration for lactating cows with 3 levels (0, 50, and 100%) of forage dry matter intake. Several series of dynamic regression models were fitted. One of these models explained emission of ammonia by the nutritional factors and the temperature; another model explained ammonia emission by the bulk milk urea content and the temperature. The ammonia emission from the barn increased when levels of rumen-degradable protein balance increased. Furthermore, at a given level of rumen-degradable protein balance, the emission of ammonia correlated positively with the corn silage content in the forage ration. However, this correlation was not causal, but was the result of interaction between corn silage proportion and intake of ileal digestible protein. The bulk milk urea content and the temperature correlated strongly with the ammonia emission from the barn; the selected model accounted for 76% of the variance in emission. It was concluded that the emission of ammonia from naturally ventilated dairy cow barns was strongly influenced by diet. The emission can be reduced approximately 50% by reducing the rumen-degradable protein balance of the ration from 1000 to 0 g/cow per d. The milk urea content is a good indicator of emission reduction. |
| Databáze: | OpenAIRE |
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