The cold tolerance of beef and dairy type calves in the first weeks of life

1978 ◽  
Vol 26 (1) ◽  
pp. 85-92 ◽  
Author(s):  
A. J. F. Webster ◽  
J. G. Gordon ◽  
R. McGregor
Keyword(s):  
Heat Loss ◽  
Air Temperature ◽  
Environmental Temperature ◽  
Metabolizable Energy ◽  
Milk Replacer ◽  
Critical Temperatures ◽  
Total Heat Loss ◽  
External Insulation ◽  
Air Temperatures ◽  
Tissue Insulation

ABSTRACT1. British Friesian (F) and Hereford × British Friesian (H × F) male calves were raised from about 3 days to 8 weeks of age at air temperatures of 5, 10 or 15°C. They were given a milk replacer diet supplying 950 kJ metabolizable energy/kg M0·75.24 h.2. There was no effect of environmental temperature on weight gain in calves of either type.3. Total heat loss measured in a direct calorimeter, increased by about 5 kJ/kg M0·75.24 h per °C fall in air temperature. It was the same whether calves were penned singly or in pairs. Heat loss from F calves was slightly, but not significantly, greater at all temperatures than from H × F calves.4. The proportion of heat lost by evaporation (a measure of environmental warmth) increased with increasing air temperature and was greater for H × F than for F calves at 15°C.5. Tissue insulation and external insulation values were similar for H × F and F calves. The calculated lower critical temperatures of the F and H × F calves were 10 and 8°C respectively.6. The results are discussed in relation to the housing requirements of young calves.

Energy exchanges of veal calves in relation to body weight, food intake and air temperature

1976 ◽  
Vol 23 (1) ◽  
pp. 35-42 ◽  
Author(s):  
A. J. F. Webster ◽  
J. G. Gordon ◽  
J. S. Smith
Keyword(s):  
Body Weight ◽  
Heat Loss ◽  
Heat Production ◽  
Live Weight ◽  
Milk Replacer ◽  
Total Heat Loss ◽  
Direct Calorimetry ◽  
Veal Calves ◽  
Air Temperatures ◽  
Energy Retention

SUMMARY1. Two series of energy balance trials were conducted with British Friesian veal calves. In the first, calves were given a milk replacer diet at three different planes of nutrition. In the second, calves were raised from about 80 to 180 kg at four air temperatures, 5°, 10°, 15° and 20°.2. The net efficiency of utilization of the milk replacer diet for growth was 0·72. The effect of body size on heat production in growing calves was best expressed by an exponent of body weight slightly but not significantly below W0·75.3. Measurements of heat production estimated from respiratory exchange and heat loss measured by direct calorimetry agreed exactly at all planes of nutrition. Heat production at zero energy retention was 675 kJ/kg W0·75 per 24 hr.4. Average daily live-weight gain and total heat loss were the same at all air temperatures. Changes during growth in the partition of heat loss into its sensible and evaporative components indicated that calves acclimated progressively to the air temperatures to which they were exposed.

Influence of air humidity on the partition of heat exchanges of cattle

1972 ◽  
Vol 78 (2) ◽  
pp. 303-307 ◽  
Author(s):  
J. A. McLean ◽  
D. T. Calvert
Keyword(s):  
Body Temperature ◽  
Heat Loss ◽  
Air Temperature ◽  
Heat Production ◽  
Total Heat ◽  
Evaporative Heat Loss ◽  
Air Humidity ◽  
Total Heat Loss ◽  
Air Temperatures ◽  
Heat Exchanges

SUMMARYThe balance between heat production and heat loss and the partition of heat exchanges of cattle in relation to air humidity has been studied at two different air temperatures using a direct (gradient-layer) calorimeter.Increasing humidity at 35 °C air temperature caused no significant change in heat production or in the level of total heat loss finally attained, but body temperature and respiratory activity were both increased.Increasing humidity at 15 °C air temperature caused a small reduction in heat loss by evaporation but had no effect on sensible heat loss, body temperature or respiratory frequency.Heat loss by evaporation amounted to 18% of the total heat loss at 15 °C and to 84% at 35 °C.Heat loss by respiratory evaporation amounted to 54% of the total evaporative heat loss at 15 °C and to 38% at 35 °C.

Effects of environmental temperature and humidity on evaporative heat loss through firefighter suit materials made with semi-permeable and microporous moisture barriers

2021 ◽  
pp. 004051752110265
Author(s):  
Huipu Gao ◽  
Anthoney Shawn Deaton ◽  
Xiaomeng Fang ◽  
Kyle Watson ◽  
Emiel A DenHartog ◽  
...  
Keyword(s):  
Heat Loss ◽  
Environmental Temperature ◽  
Moisture Absorption ◽  
Evaporative Heat Loss ◽  
Total Heat Loss ◽  
Evaporative Resistance ◽  
Environmental Testing ◽  
Permeable Barrier ◽  
Moisture Condensation ◽  
Moisture Barriers

The goal of this research was to understand how firefighter protective suits perform in different operational environments. This study used a sweating guarded hotplate to examine the effect of environmental temperature (20–45°C) and relative humidity (25–85% RH) on evaporative heat loss through firefighter turnout materials. Four firefighter turnout composites containing three different bi-component (semi-permeable) and one microporous moisture barriers were selected. The results showed that the evaporative resistance of microporous moisture barrier systems was independent of environmental testing conditions. However, absorbed moisture strongly affected evaporative heat loss through semi-permeable moisture barriers coated with a layer of nonporous hydrophilic polymer. Moisture absorption in mild environment (20–25°C) tests, or when testing at high humidity (>85% RH), significantly increased water vapor transmission in semi-permeable turnout systems. It was also found that environmental conditions used in the total heat loss (THL) test (25°C and 65% RH) produced moisture condensation in bi-component barrier systems, making them appear more breathable than could be expected when worn in hotter environments. Regression models successfully qualified the relationships between moisture uptake levels in semi-permeable barrier systems and evaporative resistance and THL. These findings reveal the limitations in relying on THL, the heat strain index currently called for by the NFPA 1971 Standard for Structural Firefighter personal protective equipment, and supports the need to measure turnout evaporative resistance at 35°C (Ret), in addition to THL at 25°C.

Skinfolds and resting heat loss in cold air and water: temperature equivalence

1975 ◽  
Vol 39 (1) ◽  
pp. 93-102 ◽  
Author(s):  
R. M. Smith ◽  
J. M. Hanna
Keyword(s):  
Heat Transfer ◽  
Water Temperature ◽  
Heat Loss ◽  
Air Temperature ◽  
Indirect Calorimetry ◽  
Cold Water ◽  
Heat Conductance ◽  
Air Temperatures ◽  
Body Core ◽  
Male Subjects

Fourteen male subjects with unweighted mean skinfolds (MSF) of 10.23 mm underwent several 3-h exposures to cold water and air of similar velocities in order to compare by indirect calorimetry the rate of heat loss in water and air. Measurements of heat loss (excluding the head) at each air temperature (Ta = 25, 20, 10 degrees C) and water temperature (Tw = 29–33 degrees C) were used in a linear approximation of overall heat transfer from body core (Tre) to air or water. We found the lower critical air and water temperatures to fall as a negative linear function of MSF. The slope of these lines was not significantly different in air and water with a mean of minus 0.237 degrees C/mm MSF. Overall heat conductance was 3.34 times greater in water. However, this value was not fixed but varied as an inverse curvilinear function of MSF. Thus, equivalent water-air temperatures also varied as a function of MSF. Between limits of 100–250% of resting heat loss the followingrelationships between MSF and equivalent water-air temperatures were found (see article).

Effect of air temperature and energy intake on body mass, body composition and energy requirements in sheep

2002 ◽  
Vol 138 (2) ◽  
pp. 221-226 ◽  
Author(s):  
A. ALLAN DEGEN ◽  
B. A. YOUNG
Keyword(s):  
Energy Intake ◽  
Body Mass ◽  
Air Temperature ◽  
Total Body Water ◽  
Metabolizable Energy ◽  
Energy Requirements ◽  
Water Volume ◽  
Air Temperatures ◽  
Metabolizable Energy Intake ◽  
Total Body

Body mass was measured and body composition and energy requirements were estimated in sheep at four air temperatures (0 °C to 30 °C) and at four levels of energy offered (4715 to 11785 kJ/day) at a time when the sheep reached a constant body mass. Final body mass was affected mainly by metabolizable energy intake and, to a lesser extent, by air temperature, whereas maintenance requirements were affected mainly by air temperature. Mean energy requirements were similar and lowest at 20 °C and 30 °C (407·5 and 410·5 kJ/kg0·75, respectively) and increased with a decrease in air temperature (528·8 kJ/kg0·75 at 10 °C and 713·3 kJ/kg0·75 at 0 °C). Absolute total body water volume was related positively to metabolizable energy intake and to air temperature. Absolute fat, protein and ash contents were all affected positively by metabolizable energy intake and tended to be related positively to air temperature. In proportion to body mass, total body water volume decreased with an increase in metabolizable energy intake and with an increase in air temperature. Proportionate fat content increased with an increase in metabolizable energy intake and tended to increase with an increase in air temperature. In contrast, proportionate protein content decreased with an increase in metabolizable energy intake and tended to decrease with an increase in air temperature. In all cases, the multiple linear regression using both air temperature and metabolizable energy intake improved the fit over the simple linear regressions of either air temperature or metabolizable energy intake and lowered the standard error of the estimate. The fit was further improved and the standard error of the estimate was further lowered using a polynomial model with both independent variables to fit the data, since there was little change in the measurements between 20 °C and 30 °C, as both air temperatures were most likely within the thermal neutral zone of the sheep. It was concluded that total body energy content, total body water volume, fat and protein content of sheep of the same body mass differed or tended to differ when kept at different air temperatures.

THE INFLUENCE OF ENVIRONMENTAL TEMPERATURE AND HUMIDITY ON SHOCK PRODUCED BY A CLAMPING PROCEDURE

1959 ◽  
Vol 37 (2) ◽  
pp. 165-174
Author(s):  
R. E. Haist ◽  
Rebeka Moscarello ◽  
T. L. Friedlich ◽  
J. R. Hamilton
Keyword(s):  
Air Temperature ◽  
Significant Influence ◽  
Environmental Temperature ◽  
Limb Ischemia ◽  
Optimum Temperature ◽  
Standard Temperature ◽  
Air Temperatures ◽  
Temperature And Humidity ◽  
Different Temperatures ◽  
Environmental Temperatures

The influence of environmental temperature on the development of shock produced by a clamping technique in rats was studied. In experiments in which the animals were subjected to different environmental temperatures during the period of limb ischemia, the best survival was obtained with an air temperature of 15 °C. At 9.5 °C and 40 °C the rats did not survive the 10-hour clamping period. When the clamping was carried out at a standard temperature (27 °C) and the rats were then transferred to a room at different temperatures just prior to clamp release, the best survival was obtained at or near a temperature of 24 °C. The temperature in the colon of the shocked rats fell quickly in a cooler environment and rose in a warmer one. When chlorpromazine (0.35 mg/100 g rat) was given at the time of clamp removal to rats kept thereafter at 9.4 °C, 20–21 °C, 24 °C, and 30 °C, survival was significantly prolonged at air temperatures of 20–21 °C, but not at 9.4 °C, 24 °C, or 30 °C. Changes in humidity had no significant influence on survival. The experiments show that the optimum temperature during the period of ischemia is different from that for hindering the development of shock following a period of ischemia.

THE INFLUENCE OF ENVIRONMENTAL TEMPERATURE AND HUMIDITY ON SHOCK PRODUCED BY A CLAMPING PROCEDURE

1959 ◽  
Vol 37 (1) ◽  
pp. 165-174
Author(s):  
R. E. Haist ◽  
Rebeka Moscarello ◽  
T. L. Friedlich ◽  
J. R. Hamilton
Keyword(s):  
Air Temperature ◽  
Significant Influence ◽  
Environmental Temperature ◽  
Limb Ischemia ◽  
Optimum Temperature ◽  
Standard Temperature ◽  
Air Temperatures ◽  
Temperature And Humidity ◽  
Different Temperatures ◽  
Environmental Temperatures

The influence of environmental temperature on the development of shock produced by a clamping technique in rats was studied. In experiments in which the animals were subjected to different environmental temperatures during the period of limb ischemia, the best survival was obtained with an air temperature of 15 °C. At 9.5 °C and 40 °C the rats did not survive the 10-hour clamping period. When the clamping was carried out at a standard temperature (27 °C) and the rats were then transferred to a room at different temperatures just prior to clamp release, the best survival was obtained at or near a temperature of 24 °C. The temperature in the colon of the shocked rats fell quickly in a cooler environment and rose in a warmer one. When chlorpromazine (0.35 mg/100 g rat) was given at the time of clamp removal to rats kept thereafter at 9.4 °C, 20–21 °C, 24 °C, and 30 °C, survival was significantly prolonged at air temperatures of 20–21 °C, but not at 9.4 °C, 24 °C, or 30 °C. Changes in humidity had no significant influence on survival. The experiments show that the optimum temperature during the period of ischemia is different from that for hindering the development of shock following a period of ischemia.

Comparison of non-evaporative heat transfer in different cattle breeds

1985 ◽  
Vol 36 (3) ◽  
pp. 497 ◽  
Author(s):  
VA Finch
Keyword(s):  
Heat Loss ◽  
Air Temperature ◽  
Heat Storage ◽  
Absolute Humidity ◽  
Total Heat ◽  
Evaporative Heat Loss ◽  
Excessive Sweating ◽  
Total Heat Loss ◽  
Evaporative Water ◽  
Rate Of Increase

Tissue conductance and non-evaporative heat loss from the skin were determined from measurements of body temperature, evaporative water loss, metabolic rate and heat storage in six steers in each of three breeds, Brahman (B), Brahman x Hereford-Shorthorn (BX) and Shorthorn (S). A group of six steers, two from each breed, remained in a climate room set at 25�C overnight, and during the following day all were exposed for 1 h to sequential increases in air temperature (28, 32, 37, 41, 43, 45�C). Each steer was measured at 25�C and after a 30-min exposure to each temperature. Tissue conductance increased with air temperature (Ta), reaching maximum values at 41�C, the rate of increase (W m-2 'C-I per degree rise in Ta) being for B 3.95, for BX 2.33 and for S 2,09. Between 41 and 45�C, tissue conductance remained constant in B but declined in BX and S with a concurrent increase in heat storage. Mean tissue conductance (W m-2 �C-1) of B was 63.5; BX, 56.1; and S, 47.8, values that were significantly different (P < 0.01). Expressed in terms of metabolic weight, the breed means of tissue conductance (litres O2 h-1 W-0.75 �C-1) were also significantly different: B, 0.56; BX, 0.43; and S, 0.33 (P < 0.005), with the relative differences similar to those calculated per unit area. Breed differences in tissue conductance may be related to variations in ability to redirect blood from the core to the skin. Non-evaporative heat loss comprised 55-65% of the total heat loss from the skin in all breeds at Ta of 25�C. The remaining heat was lost through sweating. As Ta increased and approached skin temperature, non-evaporative heat loss decreased but in B and BX remained 25% of the total heat loss from the skin. S steers, in contrast, sustained little non-evaporative heat loss as Ta increased because sweating rates increased 50% more than that required to dissipate the heat at the skin. The increase in absolute humidity of the chamber was associated with the excessive sweating in this breed.

Simulation of growth in pigs: evaluation of a model to relate thermorégulation to body protein and lipid content and deposition

1999 ◽  
Vol 68 (4) ◽  
pp. 655-679 ◽  
Author(s):  
P.W. Knap
Keyword(s):  
Food Intake ◽  
Metabolizable Energy ◽  
Critical Temperatures ◽  
Activity Increase ◽  
Body Protein ◽  
Ad Libitum ◽  
Tissue Insulation ◽  
Minimum Heat

AbstractA dynamic model for simulation of growth in pigs was extended by a module to assess maximum and minimum heat loss (HLcold, HLhot) for a given pig, to compare these figures to heat production (HP), and to take thermoregulatory action when HP< HLcold(cold conditions) or HP> HLhot(hot conditions).HLcoldand HLhotwere largely determined according to algorithms obtained from the literature, hut HLcold was made dependent on body fat depth through tissue insulation. Data to establish the relation (Ύ = 0.05 + 0.002 x X) between cold tissue insulation (Ύ in °C.m2per W) and backfat depth (X in mm) independent of body weight were obtained from the literature. The same data showed that HLhotis not related to backfat depth in pigs.Cold thermoregulatory action included an increase of ad libitum food intake. Hot thermoregulatory action included reduction of physical activity, increase of body temperature, wetting of a proportion of the skin and reduction of dia libitum food intake.A sensitivity analysis showed that the model’s output in terms of ãd libitum food intake, HP, protein deposition (Pdep) and lipid deposition (Ldep) is strongly sensitive to the characterization of the genotype being simulated. The model was used to simulate trials from the literature. Although the model does not explicitly calculate lower and upper critical temperatures, these could be adequately predicted from its output. Comparison of model output with experimental data revealed an adequate prediction of ad libitum food intake and of the partitioning of ad libitum ingested metabolizable energy (ME) into HP, Pdepand Ldepin cold, thermoneutral and hot conditions. At restricted ME intake, and especially in cold conditions, the model tends to overestimate HP and underestimate Ldep, probably because it does not take account of long-term acclimatization.

The influence of environmental temperature and plane of nutrition on heat losses from individual pigs

1971 ◽  
Vol 13 (2) ◽  
pp. 295-302 ◽  
Author(s):  
W. H. Close
Keyword(s):  
Body Weight ◽  
Heat Loss ◽  
Body Surface ◽  
Environmental Temperature ◽  
Heat Losses ◽  
Total Rate ◽  
Total Heat Loss ◽  
Feeding Level ◽  
Low Level ◽  
Significant Difference

SUMMARY1. The total rate of heat loss from individual pigs (20 to 40 kg body weight) was measured over 6-hr periods in a small heat sink calorimeter at 7°, 20° and 30°C, with feeding levels of 34, 39, 45 and 52 g/kg body weight per day.2. Total heat loss at 7°C was significantly greater than at 20° or 30°C; there was no significant difference in heat loss between temperatures of 20° and 30°C.3. Heat loss per m2 of body surface was independent of feeding level at 7°C. At 20°C, heat loss on the high feeding level was significantly greater than that on the low level, and at 30°C heat loss on both the low and medium feeding levels was significantly greater than that on the very low level.

Sign in / Sign up

Export Citation Format

Share Document