Effect of pasture type (alfalfa vs. grass) on methane and carbon dioxide production by yearling beef heifersстатья из журнала
Аннотация: The objective of this study was to determine effect of pasture type on methane and carbon dioxide production by heifers grazing alfalfa or grass pastures at three sites across western Canada. All pastures were intensively managed so that heifers had ad libitum access to new forage material each day, and pastures were back-fenced to prevent the heifers accessing previously grazed areas. As measured using the sulfur hexafluoride (SF 6 ) tracer technique, total methane production at the Brandon, MB, and Swift Current, SK, sites was unaffected by pasture type (averaging 157.4 g CH 4 head -1 d -1 ), whereas at Lethbridge, AB, heifers grazing alfalfa produced more methane than did those on the grass pasture (162.8 vs. 113.5 g CH 4 head -1 d -1 ; P < 0.05). Calculated with dry matter intake (DMI) estimated by alkane analysis, methane production per unit DMI was 3 9% lower from heifers consuming grass compared with alfalfa (P < 0.001). When intakes were estimated by the Cornell Net Carbohydrate and Protein System (CNCPS) model, CH 4 production kg -1 DMI did not differ (P > 0.05) between pasture types. Loss of gross energy intake (GEI) to methane, as estimated by alkane analysis, was 6.9% for heifers grazing grass, and 9.6% for heifers grazing alfalfa (P < 0.001). Calculated using CNCPS, losses were similar (P > 0.05) between grass and alfalfa (5.8 vs. 6.2% of GEI, respectively). Carbon dioxide production per unit DMI did not differ between pasture types, irrespective of method used to estimate intake (alkanes or CNCPS). The method used to predict intake can have a major influence on calculated values when methane emissions are expressed as a percentage of GEI in grazing ruminants. At each site, CH 4 emissions and in vitro digestibility of the forage were influenced by the composition of the stand and the maturity of the forage at the time of harvest. Key words: Alfalfa, grass, grazing, legume, methane emissions
Год издания: 2006
Авторы: A. V. Chaves, L. C. Thompson, A. D. Iwaasa, Susan Scott, Merle S. Olson, C. Benchaar, D. M. Veira, Tim A. McAllister
Издательство: Canadian Science Publishing
Источник: Canadian Journal of Animal Science
Ключевые слова: Ruminant Nutrition and Digestive Physiology, Agriculture Sustainability and Environmental Impact, Muscle metabolism and nutrition
Открытый доступ: bronze
Том: 86
Выпуск: 3
Страницы: 409–418