Estimation of carbon dioxide production and energy expenditure of grazing cattle by the sulphur hexafluoride (SF₆) tracer gas technique

Abstract

. 2008. Estimation of carbon dioxide production and energy expenditure of grazing cattle by the sulphur hexafluoride (SF 6 ) tracer gas technique. Can. J. Anim. Sci. 88: 651Á 658. The purpose of the study was to explore the suitability of the sulphur hexafluoride (SF 6 ) tracer gas technique to estimate CO 2 production and energy expenditure (EE) for grazing animals on pastures typical of western Canada. During each year of a 3-yr study, CO 2 emissions were collected from 60 yearling steers on grass pastures receiving one of three fertility treatments: no manure, liquid hog manure applied as a split application (74 kg available N ha(1 ) in the spring and fall, and a single application of liquid hog manure applied at a rate of 155 kg available N ha(1 each spring. The mean CO 2 production estimate across all treatments was 542492218 L d(1 (mean9SD) with a range of 1099 to 11548 L d(1. When compared across three grazing periods in June, July and August, steers produced more (PB0.05) CO 2 in June than in either July or August. Metabolic body weight (BW 0.75 ), average daily gain (ADG), standing forage biomass, and forage neutral detergent fibre (NDF) and crude protein (CP) contents explained 33% of the variation in CO 2 production. Energy expenditure (EE) was estimated from CO 2 production by adopting an energetic equivalent of 22 kJ L(1 CO 2 and EE was calculated for animals that were not losing body weight at time of measurement. The average EE estimate was 1.290. . Energy expenditure declined as ADG and forage biomass declined, but EE was not influenced (P0.05) by fertility treatment. The EE estimate was higher (P B0.05) early in the grazing season (June) and declined as the grazing season progressed. The SF 6 tracer gas technique was able to estimate EE of individual animals without interfering with herd dynamics. The technique was also able to show differences in EE in response to pasture conditions. The results of this study suggest that the SF 6 tracer gas technique shows potential as a simple and non-invasive method of estimating CO 2 production and EE for grazing animals. Further validation under different grazing conditions and with animals undertaking different degrees of activity is required. Comparisons with other field techniques of estimating EE are also important.Key words: Energy expenditure, carbon dioxide, sulphur hexafluoride, grazing animals Stewart, A. A., Undi, M., Wilson, C., Ominski, K. H. et Wittenberg, K. M. 2008. Estimation de la production de dioxyde de carbone et de la de´pense d'e´nergie par les bovins en paissance par de´tection de l'hexafluorure de soufre (SF 6 ). Can. J. Anim. Sci. 88: 651Á658. L'e´tude devait e´tablir si la de´tection de l'hexafluorure de soufre (SF 6 ) permet d'estimer la production de CO 2 et la de´pense d'e´nergie des animaux mis a`l'herbe dans les paˆturages caracte´ristiques de l'Ouest canadien. Chaque anne´e pendant trois ans, les auteurs ont recueilli les e´missions de CO 2 de 60 bouvillons d'un an mis a`l'herbe sur des paˆturages bonifie´s de trois fac¸on...

Relationships among carbon dioxide, feed intake, and feed efficiency traits in ad libitum fed beef cattle1,2

“…In comparison, the steers in the current study were heavier (577 kg BW), had higher DMI (13.3 kg/d), and produced proportionally higher CPR (8939 g/d) and CY (679 g/kg). There have been some CPR studies (Boadi et al, 2002;Pinares-Patiño et al, 2007;Stewart et al, 2008) on grazing cattle using the sulphur hexafluoride (SF 6 ) tracer-gas technique. However, we could not compare our results with those studies as the SF 6 gas technique has been reported to overestimate individual animal CPR, although animal rankings are maintained relative to respiration chamber measurements (Boadi et al, 2002;Pinares-Patiño et al, 2007).…”

Integrating spot short-term measurements of carbon emissions and backward dietary energy partition calculations to estimate intake in lactating dairy cows fed ad libitum or restricted

“…Alternative techniques to respiratory chambers are enabling scientists to collect or record gas measurements from cattle in their own production settings (e.g., grazing, free stall). Specific examples include quantifications of (1) heat production (HP) from O 2 consumption per heartbeat (Brosh et al, 1998;Aharoni et al, 2006), (2) energy expenditure using the 13 C bicarbonate technique coupled with O 2 consumption and respiratory quotient (RQ; Junghans et al, 2007;Kaufmann et al, 2011), (3) carbon emissions using tracer techniques (Stewart et al, 2008;Madsen et al, 2010), and (4) CO 2 flux (QCO 2 ) and CH 4 flux (QCH 4 ) in animal breath (Branco et al, 2015;Dorich et al, 2015;Huhtanen et al, 2015).…”