Genetic variance and covariance components for carbon dioxide production and postweaning traits in Angus cattle

This experiment investigated phenotypic and genetic relationships between carbon dioxide production, methane emission, feed intake, and postweaning traits in Angus cattle. Respiration chamber data on 1096 young bulls and heifers from 2 performance recording research herds of Angus cattle were analyzed to provide phenotypic and genetic parameters for carbon dioxide production rate (CPR; n = 425, mean 3,010 ± SD 589 g/d) and methane production rate (MPR; n = 1,096, mean 132.8 ± SD 25.2 g/d) and their relationships with dry matter intake (DMI; n = 1,096, mean 6.15 ± SD 1.33 kg/d), body weight (BW) and body composition traits. Heritability estimates were moderate to high for CPR (0.53 [SE 0.17]), MPR (0.31 [SE 0.07]), DMI (0.49 [SE 0.08]), yearling BW (0.46 [SE 0.08]), and scanned rib fat depth (0.42 [SE 0.07]). There was a strong phenotypic (0.83 [SE 0.02]) and genetic (0.75 [SE 0.10]) correlation between CPR and MPR. The correlations obtained for DMI with CPR and with MPR were high, both phenotypically (rp) and genetically (rg) (rp: 0.85 [SE 0.01] and 0.71 [SE 0.02]; rg (0.95 [SE 0.03] and 0.83 [SE 0.05], respectively). Yearling BW was strongly correlated phenotypically (rp ≥ 0.60) and genetically (rg > 0.80) with CPR, MPR, and DMI, whereas scanned rib fat was weakly correlated phenotypically (rp < 0.20) and genetically (rg ≤ 0.20) with CPR, MPR, and DMI. The strong correlation between both CPR and MPR with DMI confirms their potential use as proxies for DMI in situations where direct DMI recording is not possible such as on pasture.

A biofilter for treating toluene vapors: performance evaluation and microbial counts behavior

A lab-scale biofilter packed with mixed packing materials was used for degradation of the toluene. Different empty bed residence times, 148.3, 74.2 and 49.4 s, were tested for inlet concentration ranging from 0.2 to 1.2 g/m3. The maximum elimination capacity of 36.0 g/(m3h) occurred at an inlet loading rate of 45.9 g/(m3h). The contribution of the lower layer was higher than other layers and always had the highest elimination capacity. The carbon dioxide production rate and distribution of micro-organisms followed toluene elimination capacities. The results of this study indicated that mixed packing materials could be considered as a potential biofilter carrier, with low pressure drop (less than 84.9 Pa/m), for treating air streams containing VOCs.

Proxies to adjust methane production rate of beef cattle when the quantity of feed consumed is unknown

The aim of the present experiment was to evaluate the utility of carbon dioxide production rate (CPR; g CO2/day) and animal weight (WT) data as proxies for feed intake to adjust methane production rate (MPR; g CH4/day) in situations where dry-matter intake (DMI) is not known. This experiment measured individual-animal DMI, MPR and CPR in the feedlot, and then again on restricted quantities of grain and roughage diets in open-circuit respiration chambers. Of the 59 cattle tested in the feedlot, 41 had MPR and CPR recorded, and 59 and 57 had test results on the restricted grain and roughage rations. Methane production relative to DMI by individual animals was calculated as CH4 yield (MY; MPR/DMI) and as residual CH4 production (RMPDMI; calculated as MPR less predicted MPR based on DMI). A second form of RMP: RMPCO2, was calculated by regressing MPR against CPR to determine whether animals were producing more or less CH4 than predicted for their CPR. Carbon dioxide production rate was positively associated with DMI in all three test phases (R2 = 0.25, 0.45 and 0.47; all P < 0.001). The associations for MY with MPR : CPR were moderate and positive, as follows: R2 = 0.49 in the feedlot test; R2 = 0.37 in the restricted-grain test; and R2 = 0.59 in the restricted-roughage test, and with RMPCO2, values of R2 were 0.57, 0.34 and 0.59 in the three test phases (all P < 0.001). The R2 for RMPDMI with MPR : CPR in all three tests were 0.50, 0.79 and 0.69, and with RMPCO2, values of R2 were 0.68, 0.79 and 0.68 (all P < 0.001). The high R2 for MY with MPR : CPR and RMPCO2 and even higher R2 for RMPDMI with MPR : CPR and RMPCO2 in all three test phases showed that CPR can be used to adjust MPR data for DMI when DMI is not recorded. In the feedlot test, where animal WT data were recorded over 70 days, MPR adjusted for WT and WT gain had R2 with MY and RMPDMI of 0.60 and 0.83, respectively (P < 0.001), offering the possibility that animal WT data determined over an extended time period could also be used as a proxy for DMI in adjustment of MPR.

Impact of 5-aminolevulinic acid with iron supplementation on exercise efficiency and home-based walking training achievement in older women

A reduction in exercise efficiency with aging limits daily living activities. We examined whether 5-aminolevulinic acid (ALA) with sodium ferrous citrate (SFC) increased exercise efficiency and voluntary achievement of interval walking training (IWT) in older women. Ten women [65 ± 3(SD) yr] who had performed IWT for >12 mo and were currently performing IWT participated in this study. The study was conducted in a placebo-controlled, double-blind crossover design. All subjects underwent two trials for 7 days each in which they performed IWT with ALA+SFC (100 and 115 mg/day, respectively) or placebo supplement intake (CNT), intermittently with a 2-wk washout period. Before and after each trial, subjects underwent a graded cycling test at 27.0°C atmospheric temperature and 50% relative humidity, and oxygen consumption rate, carbon dioxide production rate, and lactate concentration in plasma were measured. Furthermore, for the first 6 days of each trial, exercise intensity for IWT was measured by accelerometry. We found that, in the ALA+SFC trial, oxygen consumption rate and carbon dioxide production rate during graded cycling decreased by 12% ( P < 0.001) and 11% ( P = 0.001) at every workload, respectively, accompanied by a 16% reduction in lactate concentration in plasma ( P < 0.001), although all remained unchanged in the CNT trial ( P > 0.2). All of the reductions were significantly greater in the ALA+SFC than the CNT trial ( P < 0.05). Furthermore, the training days, impulse, and time at fast walking were 42% ( P = 0.028), 102% ( P = 0.027), and 69% ( P = 0.039) higher during the ALA+SFC than the CNT intake period, respectively. Thus ALA+SFC supplementation augmented exercise efficiency and thereby improved IWT achievement in older women.

Performance evaluation and kinetic studies on removal of benzene in up-flow tree bark based biofilter

This study aims to evaluate the feasibility of Phoenix dactylifera tree barks as the novel filter medium in an up flow biofilter employing mixed culture to degrade benzene. The experiments were conducted at different benzene concentrations (1.5 - 6.0 g.m-3) and EBRT (1.2- 4.7 min).The elimination capacity was found to vary linearly with inlet loading rate in the range of 0-306 g.m-3h-1. Removal efficiency of 99% was achieved when the benzene concentration was 1.5 g.m-3and decreased with increase in benzene concentration. Lower flow rates resulted in higher benzene removal efficiency. The concentration profile was observed at different heights of filter media. Temperature increase during biofiltration experiments confirmed the exothermic nature of biofiltration. The carbon dioxide production rate was related to elimination capacity by the equation CPR= 1.76EC+18. A Michaelis-Menten type model was applied and the kinetic constants, maximum elimination capacity ECmax, and saturation constant Ks, were found to be 217.4 g.m-3h-1 and 3.54 g.m-3 respectively.

The influence of temperature on the metabolic regulation and gas exchange of the Highveld scorpion, Opistophthalmus latimanus ( Koch ) ( Scorpionidae )

Adult scorpions (2.4g – 4.5 kg) were collected near Potchefstroom (26° .55’10” – 27° 10” 5”). Oxygen consumption rate (MO2) and carbon dioxide production rate (MCO2) were measured together with the metabolism of injected radioactive glucose.

Treatment of air polluted with methanol vapours in biofilters with and without percolationThis article is one of a selection of papers published in this Special Issue on Biological Air Treatment.

Air polluted with methanol vapours was treated in a biofilter and a biotrickling filter, both packed with inert materials. The effects of the nitrogen concentration present in the nutrient solution, the empty bed residence time, and the methanol inlet load, on the biofilter and biotrickling filter performance were all examined and compared. The elimination capacity, the biomass and the carbon dioxide production rates all increased with the increase of the parameters tested. The maximum elimination capacity for the biotrickling filter was 240 g·m–3·h–1 with corresponding removal efficiency of 75% and carbon dioxide production rate of 10 g·m–3·h–1, whereas the maximum elimination capacity for the biofilter was 80 g·m–3·h–1 with corresponding removal efficiency of 35% and carbon dioxide production rate of 70 g·m–3·h–1. The biomass production rate was similar for both the biofilter and the biotrickling filter. The carbon dioxide production rate was higher by a factor of 2 to 9 for the biofilter compared to the biotrickling filter.