This study assessed daily milk yield (DMY), 100-day (MY100), and 305-day (MY305) milk yield, and lactation length (LL) in purebred Ankole cattle and Ankole crossbreds, and the influence of environmental factors on these traits. Milk yield data were obtained for 865 cows and 1234 lactations and analyzed using a mixed linear model. The overall least squares mean of DMY, MY100, and MY305 across breed groups was 2.7 L (N = 1234, SD = 1.7), 262 L (N = 959, SD = 176), and 759 L (N = 448, SD = 439), respectively, while the average lactation length was 256 days (N = 960, SD = 122). All factors included (breed group, season and year of calving, and parity) were significant for yield traits, except season of calving for MY305. First-parity cows had the lowest milk production, and fourth-parity cows the highest. For all traits, pure Ankole cows had the lowest milk yield. Among the crossbreds, there was no significant difference between Ankole × Friesian, Ankole-Jersey mother × Sahiwal sire, and Ankole-Sahiwal mother × Jersey sire, or between Ankole × Sahiwal and Ankole-Sahiwal mother × Sahiwal sire. It was concluded that Ankole crosses with Friesian or Jersey can be beneficial, even under a management system of limited nutrition as in Rwanda.
The efficacy of methane (CH4) suppression using medium-chain fatty acids (MCFA) remains inconclusive, despite a number of studies on this topic are available. We thus carried out a meta-analysis to integrate the published data on different concentrations and types of MCFA such as lauric acid and myristic acid, which investigated ruminal methanogenesis and fermentation in in vitro and in vivo experiments. In vitro MCFA sources were classified either as pure MCFA (lauric acid, myristic acid and their combinations) or as natural MCFA-rich oils (canola oil enriched with lauric acids, coconut oil, krabok oil and palm kernel oil). The MCFA sources used in the in vivo studies were coconut oil, lauric acid, myristic acid and the combination of lauric and myristic acids. A total of 41 studies (20 in vitro and 21 in vivo studies) were compiled in our database, which included the data on CH4 emission, digestibility, ruminal fermentation products and microbial populations. The results showed that the amount of CH4 production per unit of digested organic matter decreased linearly under in vitro conditions (p < .01) and tended to decrease quadratically under in vivo conditions (p < .07) with increasing doses of MCFA. Populations of protozoa (p < .01) in both in vitro and in vivo responded negatively in a linear manner, whereas Archaea population diminished quadratically (p = .04) only in the in vitro conditions with increasing doses of MCFA. Increasing dietary MCFA concentrations also reduced the fibre digestibility linearly (p < .05) in both in vitro and in vivo conditions. CH4 production for different sources of MCFA decreased in following order: coconut oil > lauric acid > myristic acid > mixed lauric and myristic acids > palm kernel oil > canola oil enriched with lauric acids > krabok oil. It can be concluded that the effect of MCFA on ruminal methanogenesis depends on the amount and type of MCFA. 相似文献
Background, Aims and Scope Surfactant enhanced ex-situ soil washing can be used to remediate diesel contaminated soils. Surfactants enhance the diesel
removal from soils by two processes: mobilization and solubilization. Mobilization occurs at surfactant concentrations below
the critical micelle concentration (CMC), while solubilization occurs at surfactant concentrations beyond the CMC of the surfactant.
In this paper, the leaching of diesel from a self contaminated (10 000 mg diesel/kg) sandy-loam soil was studied using low
concentrated non-ionic surfactant solutions of Tergitol NP-10 (10-6 to 10-3 mol/L).
Methods The surface tension of the supernatant solutions of soil suspensions in non-ionic surfactant (Tergitol NP-10) solutions (10-6
to 10-3 mol/L) was measured to determine the total surfactant concentration (surfactant sorbed onto the soil + surfactant
in solution) at which micelles are present in the water phase of the soil suspension, or 'effective critical micelle concentration'
(ECMC), and to calculate the sub-CMC sorption isotherm of Tergitol NP-10 onto the soil. The diesel removal was measured by
soil leaching experiments with Tergitol solutions ranging from 10-6 to 10-3 mol/L.
Results and Discussion The sub-CMC sorption isotherm of Tergitol onto the soil could be described by the Freundlich equation. Even at very low surfactant
concentrations (10-6 mol/L) the surfactant enhanced the diesel removal from the soil. Up to the surfactants' ECMC the diesel
removal increased in a linear way with an increasing surfactant concentration in the wash water. A significant part (20%)
of the diesel oil was removed in the presence of surfactant, but in absence of micelles. Beyond the surfactants' ECMC, the
increase in diesel removal efficiency with increasing surfactant concentration was less pronounced. When the added surfactant
concentration was increased to 10-3 mol/L, which corresponds to an equilibrium surfactant concentration in the supernatant
solution (6.77.10-4 mol/L) above the CMC, the diesel oil removal was increased up to 50%. At this surfactant concentration
emulsion formation was observed.
Conclusion Surfactant aided leaching of diesel from a self-contaminated, sandy-loam soil with surfactant solutions below their ECMC
was able to remove in one step 20% of diesel from the soil by the mobilization mechanism. Succesive treatments or continuous
leaching with surfactant solutions below their ECMC was not studied but is likely to reduce the diesel contamination further
and at the same time avoid problems with emulsion formation. 相似文献
Thin zeolite films are attractive for a wide range of applications, including molecular sieve membranes, catalytic membrane reactors, permeation barriers, and low-dielectric-constant materials. Synthesis of thin zeolite films using high-aspect-ratio zeolite nanosheets is desirable because of the packing and processing advantages of the nanosheets over isotropic zeolite nanoparticles. Attempts to obtain a dispersed suspension of zeolite nanosheets via exfoliation of their lamellar precursors have been hampered because of their structure deterioration and morphological damage (fragmentation, curling, and aggregation). We demonstrated the synthesis and structure determination of highly crystalline nanosheets of zeolite frameworks MWW and MFI. The purity and morphological integrity of these nanosheets allow them to pack well on porous supports, facilitating the fabrication of molecular sieve membranes. 相似文献
Detailed chemical maps of the lunar surface have been constructed by applying a new weighted-filter imaging technique to Apollo 15 and Apollo 16 x-ray fluorescence data. The data quality improvement is amply demonstrated by (i) modes in the frequency distribution, representing highland and mare soil suites, which are not evident before data filtering and (ii) numerous examples of chemical variations which are correlated with small-scale (about 15 kilometer) lunar topographic features. 相似文献
The Cassini Imaging Science Subsystem acquired about 26,000 images of the Jupiter system as the spacecraft encountered the giant planet en route to Saturn. We report findings on Jupiter's zonal winds, convective storms, low-latitude upper troposphere, polar stratosphere, and northern aurora. We also describe previously unseen emissions arising from Io and Europa in eclipse, a giant volcanic plume over Io's north pole, disk-resolved images of the satellite Himalia, circumstantial evidence for a causal relation between the satellites Metis and Adrastea and the main jovian ring, and information on the nature of the ring particles. 相似文献