Technical note: A facility for respiration measurements in cattle

Abstract

A respiration system consisting of 4 climate-controlled chambers and 1 set of flowmeters and analyzers was constructed and validated. Each chamber had volume of 21.10m(3) (3.68×2.56×2.24m) and was made from steel with double-glazed windows on either side enabling visual contact between animals. The chambers are independently climate-controlled and can maintain temperature and relative humidity in a range from 5 to 45°C and 30 to 80%, respectively. A flow generator and mass flowmeter continuously pull air from each chamber and a slight negative pressure inside the chamber is ensured. Air from all chambers and ambient air share a common gas analysis and data acquisition system for monitoring O2, CO2, and CH4 concentrations over the measurement period, with the cycle time set to 20min. Analyzers are regularly calibrated and the chambers have mean recoveries of 99.0 and 98.0% for CO2 and CH4, respectively. The chambers are equipped with infrared cameras and electronic feed and water bins for intake measurements, as well as sensors for monitoring animal position and heart rate. Data acquisition and analysis software is used to calculate the rate of consumption of O2 and production of CO2 and CH4. The dynamic respiration measurements are integrated with feed intake data and other sensors. The daily gas exchanges are estimated by integration to determine methane emission and heat production. We conducted a trial with 12 lactating 3/4 Holstein × 1/4 Gyr crossbred dairy cows (6 multiparous and 6 primiparous) under 2 feeding regimens (ad libitum or restricted) to validate the system. Two 22-h respiration measurements were obtained from each cow. Restricted-fed cows showed lower values for milk yield, methane emission, and heat production compared with ad libitum-fed animals. We found no difference between groups for CH4 produced per kilogram of dry matter intake. Repeatability for CH4 emission and heat production was high (0.97 and 0.92, respectively). The respiration system described herein is a useful tool for measuring the dynamic and accumulated data of heat production, methane emission, and feed intake.

Grouping crossbred Holstein x Gyr heifers according to different feed efficiency indexes and its effects on energy and nitrogen partitioning, blood metabolic variables and gas exchanges

“…After the whole tract digestibility trial, each of the four groups evaluated was transferred to the four open-circuit respiratory chambers for O 2 consumption and CO 2 and CH 4 production measurements [24]. The chambers are independently climate-controlled (relative humidity setting to 60% ± 2% and temperature to 22 ºC ± 1 o C).…”

Nutritional plans on the intake, digestibility, and performance of dairy heifers of different breed compositions

“…After the second digestibility assay, at 110 days of the experimental period, the procedures to determine the energy loss in the form of methane (CH 4 ) by the animals were started, in order to determine the ME of the diet. Two respirometric chambers were used, adopting the procedures and system specifications described by Machado et al (2016). The quantification of the energy loss by CH 4 production was computed assuming the value of 9.45 kcal L -1 methane (Brouwer, 1965).…”

“…Although about 80% of the milk produced in the country comes from cows with the Gyr and Holstein breeds in their genetic composition (Silva et al, 2016), national producers still use data from international committees for the formulation and adjustment of diets, since the available information on the nutritional requirements of Zebu and Crossbred dairy animals is still scarce. Recently, the advances in the investigation of calorimetry-respirometry measurements for dairy cattle (Machado et al, 2016) made it possible to determine nutritional requirements and energy efficiency without the need for animal sacrifice, one of the limiting factors of this type of study due to the high cost of specialized animals for milk production.…”

Assessment of the accuracy of open-circuit respiration chambers for measuring enteric methane emissions in cattle

“…Open-circuit respiration chamber methodology is the most precise method for measuring enteric methane emissions (Gerrits and Labussière 2015). This technique involves an animal being introduced into chambers and outside air is passed through the chambers and measurements are taken of the differences in concentrations of gases (CO2, O2, CH4) in the incoming and outgoing air (Grainger et al, 2007;Machado et al, 2016). Appropriate calibration of respiration chambers is a necessary step for accurate measurement of methane emitted by cattle in order to prevent underestimating or overestimating methane emissions that may bias national inventories (Gardiner et al, 2015).…”