Effect of air temperature on the abomasal and small intestinal digestion of a milk substitute diet given to young calves

1989 ◽  
Vol 48 (1) ◽  
pp. 67-74 ◽  
Author(s):  
M. S. Cockram ◽  
T. G. Rowan
Keyword(s):  
Proteolytic Activity ◽  
Air Temperature ◽  
Controlled Environment ◽  
Apparent Digestibility ◽  
Air Temperatures ◽  
Intestinal Digestion ◽  
Milk Substitute ◽  
Small Intestinal ◽  
Environment Chamber

ABSTRACTTwelve Friesian calves were each fitted with an abomasal cannula. The calves were placed in a controlled environment chamber and given a milk substitute diet in buckets at 12-h intervals. The calves were exposed to air temperatures of 25°C from 4 to 10 days of age, 5°C from 11 to 14 days of age, and 25°C at 15 days of age. At 9, 10, 11, 14 and 15 days of age, the abomasal contents of the calves were sampled at 2-h intervals and the temperature and pH of the abomasal contents were recorded at 40-min intervals for a period of 12 h. The rectal and abomasal temperatures of the calves were lower at 11 days of age than at 10 days of age, and were greater at 15 days of age than at 14 days of age (P < 0·05).In a similar experiment four Friesian calves were each fitted with an ileal re-entrant cannula. The calves were exposed to air temperatures of 25°C from 5 to 19 days of age, 5°C from 20 to 26 days of age, and 25CC at 27 days of age. At 18, 19, 20, 26 and 27 days of age the ileal contents of the calves were collected and sampled for a period of 12 h.No significant effects of the air temperatures of 25° and 5°C on the abomasal digestion (acidity and proteolytic activity of the abomasal contents) and ileal apparent digestibility of the diet were found.

scholarly journals Experimental Study of Temperature Effect on Human Skin: Discussion of Methodology

2013 ◽  
Vol 10 ◽  
pp. 71-76 ◽  
Author(s):  
Ahmad Rasdan Ismail ◽  
Abu Bakar Rosli ◽  
Norfadzilah Jusoh
Keyword(s):  
Relative Humidity ◽  
Air Temperature ◽  
Experimental Studies ◽  
Controlled Environment ◽  
Cooling Conditions ◽  
Air Temperatures ◽  
Local Supply ◽  
Thermoregulatory System ◽  
Environment Chamber ◽  
Basic Features

This paper present the discussion of methods used in experimental studies of thermal comfort that only focus on the effect skin temperature of human. The study was conducted human subject tests in a controlled environment chamber for cooling conditions. This study was measure in the test climate chamber at Universiti Malaysia Pahang. Three broad methodology categories are compared which are experiments in which subjects have control of air temperature, relative humidity or neither. The local supply air temperatures were at 19, 25 and 32 °C while relative humidity was at 40, 55 and 70%. Together with a previously proposed diagram of basic features of the human thermoregulatory system may be used to specify limits for air temperature and relative humidity in the indoor environment.

scholarly journals Using Leaf Temperature to Improve Simulation of Heat and Drought Stresses in a Biophysical Model

Plants ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 8 ◽  
Author(s):  
Ruchika S. Perera ◽  
Brendan R. Cullen ◽  
Richard J. Eckard
Keyword(s):  
Heat Stress ◽  
Air Temperature ◽  
Energy Budget ◽  
Perennial Ryegrass ◽  
Measured Data ◽  
Leaf Temperature ◽  
Biophysical Model ◽  
Controlled Environment ◽  
Air Temperatures ◽  
Environment Experiment

Despite evidence that leaf temperatures can differ by several degrees from the air, crop simulation models are generally parameterised with air temperatures. Leaf energy budget is a process-based approach that can be used to link climate and physiological processes of plants, but this approach has rarely been used in crop modelling studies. In this study, a controlled environment experiment was used to validate the use of the leaf energy budget approach to calculate leaf temperature for perennial pasture species, and a modelling approach was developed utilising leaf temperature instead of air temperature to achieve a better representation of heat stress impacts on pasture growth in a biophysical model. The controlled environment experiment assessed the impact of two combined seven-day heat (control = 25/15 °C, day/night, moderate = 30/20 °C, day/night, and severe = 35/25 °C, day/night) and drought stresses (with seven-day recovery period between stress periods) on perennial ryegrass (Lolium perenne L.), cocksfoot (Dactylis glomerata L.), tall fescue (Festuca arundinacea Schreb.) and chicory (Cichorium intybus L.). The leaf temperature of each species was modelled by using leaf energy budget equation and validated with measured data. All species showed limited homeothermy with the slope of 0.88 (P < 0.05) suggesting that pasture plants can buffer temperature variations in their growing environment. The DairyMod biophysical model was used to simulate photosynthesis during each treatment, using both air and leaf temperatures, and the patterns were compared with measured data using a response ratio (effect size compared to the well-watered control). The effect size of moderate heat and well-watered treatment was very similar to the measured values (~0.65) when simulated using T leaf, while T air overestimated the consecutive heat stress impacts (0.4 and 0). These results were used to test the heat stress recovery function (Tsum) of perennial ryegrass in DairyMod, finding that recovery after heat stress was well reproduced when parameterized with T sum = 20, while T sum = 50 simulated a long lag phase. Long term pasture growth rate simulations under irrigated conditions in south eastern Australia using leaf temperatures predicted 6–34% and 14–126% higher pasture growth rates, respectively at Ellinbank and Dookie, during late spring and summer months compared to the simulations using air temperatures. This study demonstrated that the simulation of consecutive heat and/or drought stress impacts on pasture production, using DairyMod, can be improved by using leaf temperatures instead of air temperature.

The effects of environmental temperature and feeding pattern on the performance of artificially-reared lambs fed cold milk substitute

1972 ◽  
Vol 15 (2) ◽  
pp. 177-182 ◽  
Author(s):  
M. J. Gibb ◽  
P. D. Penning
Keyword(s):  
Air Temperature ◽  
Dry Matter ◽  
Environmental Temperature ◽  
Dry Matter Intake ◽  
Air Temperatures ◽  
Milk Substitute ◽  
Ad Libitum ◽  
Temperature Levels ◽  
Environmental Air ◽  
Similar Growth

SUMMARYAn experiment was carried out using lambs reared from 1 day to 23 days of age on milk substitute given either ad libitum or at a restricted rate of 250 g dry matter per day, in rooms maintained at three temperatures, 7, 14 and 21°C.Lambs fed milk substitute ad libitum showed similar growth rates (about 365 g per day) at all environmental air temperatures. Total dry-matter intake of milk substitute per lamb over 22 days was slightly higher in those kept in an environmental air temperature of 7°C. The efficiency of lambs in the 7°C environment was lower than those in the 14 and 21°C environments.When dry-matter intake was held constant, at the restricted level, growth rate increased linearly between 237 and 265 g per day as the environmental air temperature was increased.At each of these temperature levels the restricted-rate lambs were more efficient than the respective lambs fed ad libitum.

Effects of Feeding Level, Air Speed and Temperature on digestibility and Growth in the Calf

1984 ◽  
Vol 1984 ◽  
pp. 140-140
Author(s):  
M. S. Cockram ◽  
T. G. Rowan
Keyword(s):  
Dry Matter ◽  
Continuous Exposure ◽  
Apparent Digestibility ◽  
Water Excretion ◽  
Exposure To Cold ◽  
Air Temperatures ◽  
Lower Critical Temperature ◽  
Milk Substitute ◽  
Air Speed ◽  
Cattle And Sheep

In the first 3 weeks of age the calf is most susceptible to diarrhoea. In a review of the literature, Williams (1977) concluded that the lower critical temperature of 3-day-old calves on restricted levels of feeding was between 9°and 13°C and by approximately one month of age was between 0° and 5°C. these temperatures can be increased by air movement (Blaxter and Wainmann, 1964). Grimble (1982) suggested that calves should not be exposed to air speeds greater than 0.25 m/s. Studies in older cattle and sheep, with a functional rumen, have shown that exposure to cold was associated with a lower apparent digestibility of feed, irrespective of changes in feed intake (Christopherson, 1976). Williams and Innes (1982) fed a milk substitute diet to calves from 24 to 38 days of age and compared housing the calves in air temperatures of 3° and 18°C. There were no significant differences between air temperatures in the apparent digestibilities of dry matter (DM), fat and nitrogen (N) (p>0.05) but there were significant increases in faecal water excretion and significant decreases in water intakes and urine volumes at 3° compared to 18°C (p<0.05). The present experiment was designed to determine the effects, at different feeding levels, of continuous exposure to cold (10°C) compared with warm (25°C) air and to low (<0.2 m/s) compared with high (>3.0 m/s) air speeds on (a) the apparent digestibility of a high fat milk substitute diet, (b) water intakes and faecal water excretions and (c) growth rates, in calves from 2 to 24 days of age.

Effects of air temperature, air velocity and feeding level on apparent digestibility, water intake, water loss and growth in calves given a milk substitute diet

1989 ◽  
Vol 48 (1) ◽  
pp. 51-65 ◽  
Author(s):  
M. S. Cockram ◽  
T. G. Rowan
Keyword(s):  
Air Temperature ◽  
Water Intake ◽  
Water Loss ◽  
Free Water ◽  
Total Water ◽  
Air Velocity ◽  
Feeding Level ◽  
Air Temperatures ◽  
Milk Substitute ◽  
Total Water Intake

ABSTRACTSix groups of eight 2-day-old calves were placed successively in a controlled environment chamber. Three groups were exposed to air temperatures of 10° and 25°C. A liquid diet of skimmed-milk substitute and 4 I/day of drinking (free) water was offered to each calf. Within each group, calves were allocated to either a low (<0·2 m/s) or a high (>3 m/s) air velocity and to either a low (30 g dry matter (DM) per kg M0·75per day) or a high (40 g DM per kg M0·75per day) feeding level. At 8 days of age the apparent digestibilities of DM at air temperatures of 10° and 25°C were 0·77 (s.e. 0·126) and 0·82 (s.e. 0·126) respectively (P > 0·05). The apparent digestibilities of DM were greater at the low feeding level with low air velocity than for either this feeding level with high air velocity or the high feeding level at both air velocities (P< 0·05) between which there was no significant difference (P > 0·05). At 8 days of age there were significant air temperature × air velocity (P< 001) and air velocity × feeding level interactions in the intake of free water (P< 005). There was a significant air temperature × feeding level interaction for total water intake (P< 0·05). Urinary water loss relative to total water intake was significantly greater at the low air velocity than at the high air velocity (P< 0·05).In a further two groups of eight calves given 30 g DM per kg M 75 per day at 8 days of age, the apparent digestibilities of DM at air temperatures of 10° and 25°C were 0·71 (s.e. 0·020) and 0·90 (s.e. 0·013) respectively (P< 0·01). In the same calves given 40 g DM per kg M0·75per day at 20 days of age, the apparent digestibilities of DM at air temperatures of 10° and 25°C were 0·89 (s.e. 0·009) and 0·93 (s.e. 0·011) respectively (P< 0·05). The free and total water intakes, the ratios of (total water intake-faecal water loss): total water intake and the urinary losses of water were significantly greater at the air temperature of 25°C than at 10°C (P< 0·05). Live-weight gains were lower at 10°C than at 25°C (P< 0·01).The results suggested that air temperature, air velocity and feeding level can affect the health and growth of calves less than 4 weeks of age.

On the dynamics of distribution of the American White Butterfly, Hyphantria cunea Drury, 1973 (Lepidoptera, Arctiidae), in Ukraine regarding the annual minimal air temperatures

2018 ◽  
Vol 14 (1) ◽  
pp. 44-57
Author(s):  
S. N. Shumov
Keyword(s):  
Air Temperature ◽  
Annual Reports ◽  
Complete Elimination ◽  
Hyphantria Cunea ◽  
White American ◽  
Gis Technologies ◽  
Data Analyses ◽  
Air Temperatures ◽  
Negative Temperatures

The spatial analysis of distribution and quantity of Hyphantria cunea Drury, 1973 across Ukraine since 1952 till 2016 regarding the values of annual absolute temperatures of ground air is performed using the Gis-technologies. The long-term pest dissemination data (Annual reports…, 1951–1985; Surveys of the distribution of quarantine pests ..., 1986–2017) and meteorological information (Meteorological Yearbooks of air temperature the surface layer of the atmosphere in Ukraine for the period 1951-2016; Branch State of the Hydrometeorological Service at the Central Geophysical Observatory of the Ministry for Emergencies) were used in the present research. The values of boundary negative temperatures of winter diapause of Hyphantria cunea, that unable the development of species’ subsequent generation, are received. Data analyses suggests almost complete elimination of winter diapausing individuals of White American Butterfly (especially pupae) under the air temperature of −32°С. Because of arising questions on the time of action of absolute minimal air temperatures, it is necessary to ascertain the boundary negative temperatures of winter diapause for White American Butterfly. It is also necessary to perform the more detailed research of a corresponding biological material with application to the freezing technics, giving temperature up to −50°С, with the subsequent analysis of the received results by the punched-analysis.

scholarly journals Heatwaves and Summer Urban Heat Islands: A Daily Cycle Approach to Unveil the Urban Thermal Signal Changes in Lisbon, Portugal

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 292 ◽  
Author(s):  
Ana Oliveira ◽  
António Lopes ◽  
Ezequiel Correia ◽  
Samuel Niza ◽  
Amílcar Soares
Keyword(s):  
Climate Change ◽  
Air Temperature ◽  
Wind Direction ◽  
Urban Heat Islands ◽  
Daily Cycle ◽  
Local Climate ◽  
Thermal Signal ◽  
Air Temperatures ◽  
Local Climate Change ◽  
Urban Heat

Lisbon is a European Mediterranean city, greatly exposed to heatwaves (HW), according to recent trends and climate change prospects. Considering the Atlantic influence, air temperature observations from Lisbon’s mesoscale network are used to investigate the interactions between background weather and the urban thermal signal (UTS) in summer. Days are classified according to the prevailing regional wind direction, and hourly UTS is compared between HW and non-HW conditions. Northern-wind days predominate, revealing greater maximum air temperatures (up to 40 °C) and greater thermal amplitudes (approximately 10 °C), and account for 37 out of 49 HW days; southern-wind days have milder temperatures, and no HWs occur. Results show that the wind direction groups are significantly different. While southern-wind days have minor UTS variations, northern-wind days have a consistent UTS daily cycle: a diurnal urban cooling island (UCI) (often lower than –1.0 °C), a late afternoon peak urban heat island (UHI) (occasionally surpassing 4.0 °C), and a stable nocturnal UHI (1.5 °C median intensity). UHI/UCI intensities are not significantly different between HW and non-HW conditions, although the synoptic influence is noted. Results indicate that, in Lisbon, the UHI intensity does not increase during HW events, although it is significantly affected by wind. As such, local climate change adaptation strategies must be based on scenarios that account for the synergies between potential changes in regional air temperature and wind.

Effects of Air Temperature on Combustion Characteristics of LPG Diffusion Flame

2020 ◽  
Vol 1008 ◽  
pp. 128-138
Author(s):  
Ahmed M. Salman ◽  
Ibrahim A. Ibrahim ◽  
Hamada M. Gad ◽  
Tharwat M. Farag
Keyword(s):  
Air Temperature ◽  
Diffusion Flame ◽  
Nitrogen Addition ◽  
Flame Length ◽  
Combustion Characteristics ◽  
Operating Conditions ◽  
Low Oxygen ◽  
Air Temperatures ◽  
Air Stream ◽  
Wide Range

In the present study, the combustion characteristics of LPG gaseous fuel diffusion flame at elevated air temperatures were experimentally investigated. An experimental test rig was manufactured to examine a wide range of operating conditions. The investigated parameters are the air temperatures of 300, 350, 400, 450, and 500 K with constant percentage of nitrogen addition in combustion air stream of 5 % to give low oxygen concentration of 18.3 % by mass at constant air swirl number, air to fuel mass ratio, and thermal load of 1.5, 30, and 23 kW, respectively. The gaseous combustion characteristics were represented as axial and radial temperatures distributions, temperatures gradient, visible flame length and species concentrations. The results indicated that as the air temperature increased, the chemical reaction rate increased and flame volume decreased, the combustion time reduced leading to a reduction in flame length. The NO concentration reaches its maximum values near the location of the maximum centerline axial temperature. Increasing the combustion air temperature by 200 K, the NO consequently O2 concentrations are increased by about % 355 and 20 % respectively, while CO2 and CO concentrations are decreased by about % 21 and 99 % respectively, at the combustor end.

scholarly journals Quantifying the Independent Influences of Land Cover and Humidity on Microscale Urban Air Temperature Variation in Hot Summer: Methods of Path Analysis and Genetic SVR

Atmosphere ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1377
Author(s):  
Weifang Shi ◽  
Nan Wang ◽  
Aixuan Xin ◽  
Linglan Liu ◽  
Jiaqi Hou ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Land Cover ◽  
Path Analysis ◽  
Temperature Variation ◽  
Direct Effect ◽  
Air Temperature ◽  
Urban Areas ◽  
Support Vector ◽  
Urban Air ◽  
Air Temperatures

Mitigating high air temperatures and heat waves is vital for decreasing air pollution and protecting public health. To improve understanding of microscale urban air temperature variation, this paper performed measurements of air temperature and relative humidity in a field of Wuhan City in the afternoon of hot summer days, and used path analysis and genetic support vector regression (SVR) to quantify the independent influences of land cover and humidity on air temperature variation. The path analysis shows that most effect of the land cover is mediated through relative humidity difference, more than four times as much as the direct effect, and that the direct effect of relative humidity difference is nearly six times that of land cover, even larger than the total effect of the land cover. The SVR simulation illustrates that land cover and relative humidity independently contribute 16.3% and 83.7%, on average, to the rise of the air temperature over the land without vegetation in the study site. An alternative strategy of increasing the humidity artificially is proposed to reduce high air temperatures in urban areas. The study would provide scientific support for the regulation of the microclimate and the mitigation of the high air temperature in urban areas.

scholarly journals Interactions between starch source and gelatinisation degree on performance and small intestinal digestion in broiler chickens

2021 ◽  
pp. 1-11
Author(s):  
K. Itani ◽  
J. Ø. Hansen ◽  
B. Kierończyk ◽  
A. Benzertiha ◽  
P. P. Kurk ◽  
...  
Keyword(s):  
Broiler Chickens ◽  
Intestinal Digestion ◽  
Small Intestinal
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