Thermosensitivity of Bos indicus cattle and their F1, crosses with three breeds of Bos taurus

1991 ◽  
Vol 52 (1) ◽  
pp. 57-65 ◽  
Author(s):  
Khub Singh ◽  
N. K. Bhattacharyya

ABSTRACTResting heat production (H), respiratory rate (RR) and rectal temperature (Tr) were measured at different controlled temperatures (Tt) in Hariana (Bos indicus) and its F, crosses with Jersey (JH), Brown Swiss (BH) and Holstein Friesian (FH) (Bos taurus) breeds and the values obtained were used to assess their relative thermosensitivity.The lowest Tt at which H significantly decreased from that at 17°c was 32°c for Hariana, JH and BH and 27°c for FH after exposure for 8 days. The corresponding values after exposure for 18 days were 37°c for Hariana and 32°c for all the three crossbred groups. Differences between the genetic groups were also significant. The lowest Tt at which metabolizable energy (ME) decreased significantly in comparison with those at 17CC was 32°c in all the genetic groups. The differences in ME intake between genetic groups were significant only at 32°c Tt. The lowest Tt at which RR significantly increased from those at 17°c were 32°c in Hariana, 27°c in JH, BH and FH for both 5 to 7 and 15 to 17 days of exposure. The corresponding Tt for increase in Tr was 37°c in Hariana, 32°c in JH and 27°c in BH and FH at both 5 to 7 and 15 to 17 days of exposure.The ambient temperature at which H would have significantly decreased and RR and Tr increased from the respective values at 17CC Tt were calculated curvilinearly for different genetic groups. There were differences in these values of calculated ambient temperatures between genetic groups and between exposure durations in respect of H, RR, and Tr, indicating differences in thermosensitivity.

1985 ◽  
Vol 53 (2) ◽  
pp. 301-305 ◽  
Author(s):  
Khub Singh ◽  
N. K. Bhattacharyya

1. Resting heat production, 18 h post-feeding, was studied in Hariana cattle (Bos indicus; Zebu) and in their F1 crosses with Jersey, Brown Swiss and Holstein Friesian, at 18.5° ambient temperature in a psychrometric chamber at different ages.2. There was no significant change in the resting heat production on a per kg body-weight (W)0.75 per 24 h basis from 16–19 to 37–40 months of age in any of the genetic groups. The daily resting heat production, however, increased with increases in body-weight and age.3. The resting heat production in all three F1 crosses was higher than that in Hariana cattle. Among the crosses, the resting heat production was highest in the Holstein Friesian x Hariana and lowest in the Jersey x Hariana.4. Metabolizable energy (ME) intake per 24 h was significantly different between genetic groups and in different age groups. However, ME intake per kg W0.75 was not significantly different between genetic groups.


1992 ◽  
Vol 55 (3) ◽  
pp. 397-405 ◽  
Author(s):  
J. W. Schrama ◽  
A. Arieli ◽  
M. J. W. Heetkamp ◽  
M. W. A. Verstegen

AbstractSeven groups of five or six Holstein-Friesian male calves were transported to an experimental farm at 2 to 3 days of age. At 6 days of age, heat production (HP) and metabolizable energy (ME) intake were measured for an 8-day period. During this period, calves were exposed to various ambient temperatures: 6, 9, 12 and 15°C. Ambient temperature was constant within days, but changed between days. Calves were fed below (four groups) or near (three groups) the maintenance requirements (290 or 460 kJ ME per kg M0·75 per day).From 6 to 14 days of age the lower critical temperature (Tc) was 12·5°C and HP increased by 8·4 kJ/kg M0·75 per day per °Cfall in ambient temperature below Tc. Both Tc and increase in HP below Tc were not affected by feeding level. Rectal temperature was lower at low ambient temperatures. The decrease in rectal temperature with ambient temperature was greatest at the low feeding level.During the experimental period, calves were not in a steady-state regarding energy metabolism. Heat production decreased with time. This decrease was affected by feeding level and ambient temperature. After arrival, the influence of both ambient temperature and feeding level on the energy metabolism of young calves increased with time.


1973 ◽  
Vol 81 (1) ◽  
pp. 173-177 ◽  
Author(s):  
R. H. Davis ◽  
O. E. M. Hassan ◽  
A. H. Sykes

SummaryEnergy balances have been determined, using the comparative slaughter procedure, over 3-week periods on groups of laying hens kept at ambient temperatures of 7·2, 15·6, 23·9, 29·4 and 35 °C.Energy intake declined as the environment became warmer (kcal ME/kg¾/day = 203· 1·13°C); heat production, as measured by the difference between energy intake and energy retention, also declined with increasing ambient temperature (kcal/kg¾/day = 151 – 1·11°C). There was a linear relationship between heat production and ambient temperature with no thermoneutral zone or critical temperature.The energy available for egg production remained almost constant at 50 kcal/kg¾/day equivalent to a rate of egg production of 82% at each ambient temperature.


1970 ◽  
Vol 75 (3) ◽  
pp. 397-402 ◽  
Author(s):  
K. G. Johnson

SUMMARYSweating rate and the electrolyte content of secretions from the skin of cattle have been measured on five Bos taurus and five B. indicus cross-bred cows by absorbing secretions into filter papers under polythene disks applied to shaved skin areas on the shoulder, sacral and lumbar regions for 5 min. The increase in weight of the filter paper was taken as a measure of sweating rate and the distilled water eluate from the filter paper was analysed for sodium and potassium. Animals were exposed for 4 h to air temperatures of 20–45 °C at 30% r.h., and for 5–7 h to air temperatures of 40 and 45 °C at 40% r.h. Estimated sweating rates were low by comparison with previously reported values, probably due to rising levels of humidity under the polythene disks during exposure to the skin. B. indicus cross-bred cows had higher sweating rates than B. taurus cows at high air temperatures but the difference between the groups was not significant statistically. Sweating rates were generally highest on the shoulder and lowest on the lumbar region.The amounts of sodium and potassium recovered from filter papers were small and very variable at low air temperatures but increased significantly with air temperature (P < 0·01). No significant differences in the amounts of electrolyte recovered from filter papers were recorded between the species groups or between different sites of collection. The secretions from cattle skin at high ambient temperatures contained at least four to five times as much potassium as sodium. Total sodium and potassium loss through the skin of these experimental animals at the highest ambient temperatures was estimated to be no more than 1–3 % of the sodium and potassium intake in the feed. Absorbing sweat on to filter paper as a method of measuring sweating rate and sweat composition is rather less satisfactory for use with cattle than with man.


1986 ◽  
Vol 106 (3) ◽  
pp. 433-436 ◽  
Author(s):  
Jennifer C. Sneddon

SummaryTwo steers (Bos indicus and Bos indicus x Bos taurus) were acclimatized to an ambient temperature of 30 °C before working at this temperature on two treadmills (gradients 0 and 6°) for 2 h (one on each treadmill) whilst carrying a load equivalent to 10% of body weight. The study was then repeated at an ambient temperature of 15 °C. The effect of variation between animals, ambient temperature and rate of energy expenditure were tested on the linear regression model EEw = A PHR + B (where EEw is the energy expenditure (w/kg0·75) and PHR is the percentage increase of working heart rate over resting heart rate).Animal and ambient temperature had no significant effect on the model. The gradient of the regression line was significantly greater (P < 0·01) when the animals were expending energy at the higher rate (about 30 W/kg live weight0·75) than when they were expending energy at the lower rate (about 14 W/kg live weight0·75).


1979 ◽  
Vol 57 (12) ◽  
pp. 1401-1406 ◽  
Author(s):  
M. T. Lin ◽  
Andi Chandra ◽  
T. C. Fung

The effects of both systemic and central administration of phentolamine on the thermoregulatory functions of conscious rats to various ambient temperatures were assessed. Injection of phentolamine intraperitoneally or into a lateral cerebral ventricle both produced a dose-dependent fall in rectal temperature at room temperature and below it. At a cold environmental temperature (8 °C) the hypothermia in response to phentolamine was due to a decrease in metabolic heat production, but at room temperature (22 °C) the hypothermia was due to cutaneous vasodilatation (as indicated by an increase in foot and tail skin temperatures) and decreased metabolic heat production. There were no changes in respiratory evaporative heat loss. However, in the hot environment (30 °C), phentolamine administration produced no changes in rectal temperature or other thermoregulatory responses. A central component of action is indicated by the fact that a much smaller intraventricular dose of phentolamine was required to exert the same effect as intraperitoneal injection. The data indicate that phentolamine decreases heat production and (or) increases heat loss which leads to hypothermia, probably via central nervous system actions.


1986 ◽  
Vol 64 (4) ◽  
pp. 889-892 ◽  
Author(s):  
E. Don Stevens ◽  
J. Ferguson ◽  
V. G. Thomas ◽  
E. Hohtola

We estimated heat production in Japanese quail (Coturnix coturnix japonica) by measuring oxygen uptake using open-circuit respirometry as ambient temperature was decreased gradually from 26 to 3.5 °C. At the same time, the intensity of shivering was estimated in both the leg muscles and the flight muscles by measuring electromyograms. Metabolic heat production increased in a linear fashion as ambient temperature decreased. Shivering intensity increased at the same linear rate in the leg muscles as in the flight muscles as ambient temperature decreased. The leg muscles produce a substantial fraction (about 1/4) of the total shivering heat production at low ambient temperatures. Shivering occurred in bursts; the onset of a burst in the leg muscles was precisely synchronized with the onset of a burst in the flight muscles.


1965 ◽  
Vol 20 (3) ◽  
pp. 405-410 ◽  
Author(s):  
Hermann Pohl

Characteristics of cold acclimation in the golden hamster, Mesocricetus auratus, were 1) higher metabolic rate at -30 C, 2) less shivering when related to ambient temperature or oxygen consumption, and 3) higher differences in body temperature between cardiac area and thoracic subcutaneous tissues at all ambient temperatures tested, indicating changes in tissue insulation. Cold-acclimated hamsters also showed a rise in temperature of the cardiac area when ambient temperature was below 15 C. Changes in heat distribution in cold-acclimated hamsters suggest higher blood flow and heat production in the thoracic part of the body in the cold. The thermal conductance through the thoracic and lumbar muscle areas, however, did not change notably with lowering ambient temperature. Marked differences in thermoregulatory response to cold after cold acclimation were found between two species, the golden hamster and the thirteen-lined ground squirrel, showing greater ability to regulate body temperature in the cold in hamsters. hibernator; oxygen consumption— heat production; body temperature — heat conductance; muscular activity — shivering; thermoregulation Submitted on July 6, 1964


1971 ◽  
Vol 55 (1) ◽  
pp. 223-239 ◽  
Author(s):  
BERND HEINRICH ◽  
GEORGE A. BARTHOLOMEW

The physiology of pre-flight warm-up in Manduca sexta was analysed with regard to rate of heat production, regional partitioning of heat between thorax and abdomen, and the control of blood circulation. 1. When moths which have come to equilibrium with ambient temperature undergo pre-flight warm-up, the thoracic temperature increases linearly until flight temperature (37-39 °C) is approached. 2. The rate of increase in thoracic temperature during warm-up increases directly with ambient temperature from about 2 °C/min at 15 °C to about 7.6 °C/min at 30 °C. 3. The temperature of the abdomen remains near ambient throughout the period of warm-up, but during the initial part of post-flight cooling while thoracic temperature declines sharply abdominal temperatures rise appreciably. 4. During warm-up the rate of wing vibration increases linearly with thoracic temperature. At a thoracic temperature of 15 °C the rate is about 8/sec and at 35 °C it is about 25/sec. 5. When resting animals are held by the legs they at once begin to beat their wings through a wide angle. These wing beats at any given thoracic temperature are slower than the wing vibrations characteristic of normal warm-up, but they cause thoracic temperature to increase at almost the normal rate. 6. The removal of thoracic scales causes a decrease in rate of warm-up, but in still air this does not prevent the moths from reaching flight temperature. 7. During cooling the rate of decrease in thoracic temperature is greater in live animals than in freshly killed ones. At any given difference between thoracic and ambient temperatures cooling rates are directly related to thoracic temperature. 8. In resting moths heart pulsations are usually variable with regard to rate, amplitude, rhythm, and sometimes direction, but the records of cardiac activity simultaneously obtained from thorax and abdomen show close correspondence. 9. During warm-up the records of changes in impedance from electrodes in the abdomen indicate that pulsations of the abdominal heart are either absent, greatly reduced, or at a frequency different from that simultaneously recorded from the thorax. 10. The calculated rate of heat production during warm-up is linearly related to thoracic temperature. 11. Our data are consistent with the assumption that heat produced in the thorax during warm-up is sequestered there by reduction in blood circulation between thorax and abdomen. 12. Rates of warm-up in insects are close to the values predicted on the basis of body weight from data on heterothermic birds and animals.


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