Environmental Physiology - Division Of Animal Sciences - University

, .

JULY, 1951 RESEARCH BULLETIN 481

UNIVERSITY OF MISSOURI COLLEGE OF AGRICULTURE

AGRICULTURAL EXPERIMENT STATION

J. H. LONGWELL, Di,.ecto1·

Environmental Physiology With Special Reference to Domestic Animals

XV. Influence of Environmental Temperature, 0° to l05°P., on Hair and Skin Temperatures and on the Partition of Heat Dissipation

Between Evaporative and Non-Evaporative

Cooling in Jer.c;cy and Holstein Cattle

H. J. THOMl'so�, D. M. WonsTELL, and SAMUEl. BRODY

(Publication :J.lIthorizeJ July 9, 1951)

COLUMBIA, MISSOURI

TABLE OF CONTENTS

Introduction Page

�

Methods for Measuring Surface Temperatures .................... _ ................... _ ....... _.................... 3

Data ................................................................................ -............................................................................................ 7

Avenues of Heat Loss and the Application of Newton's Law of Cooling _ ...... 14

Summary and Abstract ...................................................................................................................... , ...... _ .. 18

ACKNOWLEDGMENTS

This is a part of a broad cooperative investigation between the Departments of Agricultural Engineering and Dairy Husbandry of the Missouri Agricultural Experiment Station, University of Missouri, and the Bureau of Plant Industry, Soils, and Agricultural Engineering, Agricultural Research Administration, U. S. Department of Agricufture. The Bureau of Dairy Industry and the Bureau of Animal Industry, Agricultural Research Administration, U. S. Department of Agriculture, advised with the Bureau of Plant Industry, Soils, and Agricultural Engineering on various a�pects of this work.

Acknowledgments are made to A. C. Ragsdale, Department of Dairy Husbandry, University of Missouri, for selection of the animals, their management, and for counsel on the dairy aspects; to J. C. Wooley and M. M. Jones, Department of Agricultural Engineering, University of Mi�souri, for cooperation and counsel on the engineering aspects; and to Samuel Barrett, Engineering Aide, BPISAE, for assistance in taking the measurements.

H. J. Thompson is Resident Agricultural Engineer, and Dorothy M. Worstell, Resident Statistician, of the BPISAE.

Environmental Physiology With Specia' Reference to Domestic Anima's

xv. Influence of Environmental Temperature, 0° to 105°F., on Hair and Skin Temperatures and on the Partition of Heat Dissipation

Between Evaporative and Non-Evaporative Cooling in Jersey and Holstein Cattle

H. J. THOMPSON, D. M. WORSTELL, and SAMUEL BRODl

INTRODUCTION

Depending on size and yield, a dairy cow produces 600 to 1000 Calories, or 2400 to 4000 Btu, heat per hour.1 In cold weather this heat is useful to keep the animal warm; in hot weather it is a dangerous waste product which must be promptly dissipated to avoid overheating the body. The heat conservation in cold weather and the heat dissipation in hot weather is carried out by way of the body surface, the skin, and its appendages. The skin thus occupies a strategic position i� body-temperature regulation, the success of which is measured by the temperature gradients between skin surface, hair surface, rectal, and environmental temperatures. This bulletin is a first progress report on such a study of temperature gradients, particularly on the effect of' environmental temperature on skin and hair temperature.

METHODS FOR MEASURING SURFACE TEMPERATURE

Surface temperatures have been measured at various times with mercury thermometers, thermocouples, and radiation thermopiles.

The objection!; to a mercury thermometer for measuring surface temperature are: only a part of the thermometer bulb contacts the skin surface; it

lKibler, H. H., Brody, S., and Worstell, D. M., Influence of temperature, 50° to 105°F., on heat production and cardiorespiratory activities in dairy cattle. Univ. Missouri Ap;r. Exp. Sta. Res. Bul. 435, 1949; Kibler, H. H., and Brody, S., Influence of temperature, 50° to 5°F. and 50° to 95°F., on heat production and cardiorespiratory activities in dairy cattle. Univ. Missouri Ag. Exp. Sta. Res. Bui. 450, 1950.

4 MISSOURI AGRICULTURAL EXPERIMENT STATION

changes the skin temperature by covering the skin and by affecting the capil· lary circulation at the point of contact; it has a long-lime lag in attaining equilibrium. Therefore, the preferred methods for measuring skin tempera· ture are by thermocouple, apparently pioneered by Benedict:! and associates, and by radiation thermopile, apparently pioneered by Aldrich,3 and brought to the present state of perfection by Hardy4 and associates.

Severa! kinds of Ihermocouplcs have been used for measuring surface temperature, including th�rmocouplcs of large diameter,!' sturdy, but nol reliable, because of high thermal conductance and incomplete contact; well· insulated thermocouples:! or resistance thermometers,G not reliable because of time lag in attaining equilibrium j and bare·wire thermocouples of small diameter' (#30 Brown and Sharp or American Wire Gauge, about 0.254 mm), not so sturdy but more reliable.s The finer the wire the more precise, theo· retically, is the temperature reading.

The objection'3 to the older designs and advantages of the newer designs of thermocouples were discussed, among others, by Aldrich,3 BazeH and McClone,7 Burton,S Hardy.� and others ....

�Benedict, F. C., Miles. W. R., and Johnson, A., "The temperature of the human skin." Proc. Nat. Ac. Sc., 5, 218, 1919. Benedict, Fox, E. L, and Baker. M. L., "The surface temperature of the elephant, rhinoceros, and hippopotamus." Am. 1. Physiol.. 56, 464. 1921, and Proc. Nat. Ac. Sc., 7, 154, 1921. Benedict, "Die Temperatur der Men· schlichen Haut," Ergb. D. Physio!., 24, 594-, 1925. Benedict and Parmenter J. Physiol., 87, 633, 192ft Talbot, F. B., "The skin temperature of children." Am. J. Dis. Child., 42 965, 1937.

"Aldrich, L. 8., Smithsonian Misc. Coil., n, No. 13, 1922; 81, No.6. 192A; and 85. No. II, 1932.

·Hardy, J. D., "An instrument for measuring the radiation and surface tempera· ture of tht: skin." J. Clin. J",'est., 13, 593, 605, 615 and 817, 1934. Hardy and Soderstrom. G. F., "An improved method for measuring surface and body temperature." Rev. Sr. Instr., 8, ·H9, 1927. Hardy and DuBois, E. F., "The technics of measuring radiation and convection." J. Nutr., 15, 461, 1938.

3Bedford, T., and Wnrner, C. G., "Methods of measuring skin temperatures." J. Hyg., 34, 81, 1934.

·Soderstrom, G. F., "EI.ectrical resistant thermometers." Rev. Sc. Inslr .• 4, 285. 1933.

'Sazett, H. C, and McClone, B .• Am. J. Physio!., 82, 415. 1927. 'Burton, A. C. "A new technique for the measurement of average skin tempera·

ture." J. Nutr., 7, 481,1934. ·After the nbove was written, J. D. Findlay's excellent Mono{!rnph (Hannah

Dair)' Research Institute, Bul. 9, 1950) came to hand with a detailed disc'ussion (Ch. 9) of temperature measurement methods wilh references. amO"J! others. to R. Ej.!p:erl (J. Agr. Res., 72, 341,1946), R. L. Kirk (Proc. Roy. Soc., 1328. 166, 1944) and J. R. l\turlin (Ergeb. d. Physiol., 42, 153, 1939) on tile use of thermocouples in biology; C R. Spenl·

man (Am. J. Physio!., 146, 262, 1946) on the use of couples lor meastlrin� rectal tempera· tures in rats; J. S. Presion (J. Sc. Instl'., 23. 173. 1946) on amplifiers for use with thermo· couples; J. Elder (Onderslepoort J. Vet. Sc., 17, 141, 1941) on thermocouples for measurinj.! surfaces with very iong hnir; K. F. C, Herrington and R. Handlt:.y (J. Sci. lnslr .. 25, ·)34. 1948) on thermistors. The recent ';Physiology of Heat Rep:ulation and the Science of Clothing," edited by L. H. Newburgh, Saunders, 1949, contains much information and many references on surface temperature methods and n:lated problems, but confined to man.

RESEARCH BULLETIN 481 5

The fine-wire thermocouple can be moved rapidly over the surface, thereby avoiding changes in skin temperature at the point of contact. This fine type of "touch thermocouple" (Fig. 1) was used here for measuring temperatures over the hair cont, and of the skin between the hair. The Hardy radiometer (Fig. 2) was 31so used for measuring the temperature of the sur· faces of the hair, walls, ceiling, and floor.

The Hardy radiometer" is used for measuring the rate of infra-red radiations, by comparing the animal surface with that of a black-body (Leslie Cube) of similar temperature. Like a thermocouple. the radiation thermopile is based on the principle that an electromotive force is generated when different metals are in contact. The Hardy radiometer has eight "hot" or radia· tion junctions and eight "cold" compensaling junctions. The junctions are made by fusing .01 to .03 mm filaments of Hutchin's bismuth alloys, one containing 5 parts Sn and 95 parts Bi, and the other 3 parts Sb and 97 parts

NO_ 30 AWG COPPER-CONSTANTAN TOUCH THERMOCOUPLES C ::;========;;::::=J-- fLEXIBLE LEAO WI RES;-J;:;r===========� K TO REf. JC T. t POTENT

IOMETER,. INSULATED

1/2 I� OIA. X 4 V2 I� WOOO HAN OLE-

DOWN TO STEEL TIPS

ASSEMBLIES TAPED L ENGTH OF HANDLE

va x I X 4 IN. INSULA TlNG PLASTIC HANDLE

c K

� RUBBER BAND-f�==i;F! I : '

\ ,

: : !e,

i--SPRING STEEL .013 IN. THICK WITH WIRES SOLOERED

TO TIPS

� / \ \ HAIR Vt'i't7l'T�

flJCT. \ tfI'I,111LWPSKIN � �c ING_TRAVEL- CONTINUOUS n1 ?ECWP-OCP.1 APRO X . b IN. PER MIN.

, � o "

, , , , ,

Ie

fOR SKIN TEMPERATURE FOR HAIR AND AIR TEMPERATURES

Fig. I.-Construction features of the touch thermocouple. The dimensions arc approxi. mate. Breakage was encountered at times but did not materially hinder progress of the measure· ments. The junctions were not shidd�d when used to measure air having velocities of 30 to 50 feet per minute.

6 MISSOURI ACRICULTURAL EXPERIMENT STATION

SECTION A�A

� 9 -

RADIATION THERMOPILE ASSEMBLY

CENTI�oETERS 5

LESLIE CUBE

Fig. 2.-The Hardy Dermal Radiometer sensing element and Leslie Cube used in these measurements. Somewhat modified rrom Figure 3 by J. D. Hardy, in The Journal of Clinical Investigations, 13, 597, 1934. In application this element was neld 3 to lL hlt:llt:S away .. urn the animal's surface, viewing a relatively flat area. This reduced the time required to take the measUrement" and also errors due to local henling of the air near the animal and consequently the cold junctions of the thermopile. Even greater distances were used f<Or chamber surface temperatures to obtain measurements representing larger areas. A room temperature block was used for zeroing for chamber surfnc� tempernture; the Leslie Cube near the temperature of the animal surface was similarly used for animal surfac� temperature.

Hi. \Vhen exposing one junction to a radiation surface, a current is produced. measured by the movement of a galvanometer needle, employing a potentio

meter as null instrument . The radiation is directed to the thermopile by a

silver cone which increases sensitivity and reduces the effects of stray air currents and re·radialions within the inslTUmenl.

Detailed methods of construction, C'aiihrRtion, and use of thermocouples are given by Hukill and others,!! t:'�ld of radiometers by Hardy and othersol,9.

Electromotive force·temperalllTe relrttionships u'iieo for the 30·gauge copper· constantan thermocouples, as ml!a�ured with a Leeds and Northrup model 8662 portable semi-precision potentiomete r. were checkecflo in a bath with a mercury thermometer having a Bureau of Standard5 calibration. These values were used throughout the tf'<;.t�, �i\'ing an act:uracy on the order of O.soF. Chamber surface temperatures m(>R�tlr('d with the radiometer were checked with unmounted thermojunctions of the above wire, taped to the surfaces with one thickness of relati"f"ly tran�par('nt cellulose adhesive tape. These

�Hukil1, w. V., and others, in: "Temperature, Its Measurtment and Control in Sei,'ncc and Industry," Hcinhold Publishinj! Corporation, 1941.

IOCr. Roser, Wm. F., and Wensel, H. T., "Temperature, Its Measurement and Control in Science and Industry," Reinhold Publishing Corporation, Table 10, p. 1307, 1941.


values were found to agree within ahollt lOF. Thermometers used In the room temperature block and the Leslie (ube agreed within about 0.2°C. of the Bureau of Stendards calibratrd nlt"rcury thermometer.

The temperature of the skin surface of the cows was, then, measured with touch thermocouples; the hair surfacE' with touch thermocouples and also with the Hardy infra·red radiometer; the wall surface with radiometer; the air with touch thermocouple.

DATA The data reported in this bulletin were obtained on Jersey and Holstein

cows during two experimental periods as shown in the temperature calendar (Table 1 ) .

Other phases of these two experiments have been previously reported: Milk production and feed and water consumption, It rectal temperature, heal production and cardiorespiratory activities,l im.ensible weight loss and moislure vaporization. 1:1

The surface temperatures of the cows were measured on six spots: ba,ck, belly, right and left sides of body lbarrel), neck, and rump (Fig. 3). A,

Fig_ 3.-Location of five of the six points on the cow where touch thermocouple and radiometer measurement.; were made. The sixth point is on left side of animal.

URagsdale, A. c., Brody,S., Thompson, 1-1. J., and Wo�tell, D. 1\1., Influence of temperature, 50° to 105°F., on milk production nnd feed com:umption in dairy cattle. Univ. 1\Iissouri Agr. Exp. Stu. Res. Bul. 425. 1948. Thompson. H. J., Worstell, IJ. 1\1., and Brody,S .. Influence of temperature. 50° to 105°F., on waler consumption in dairy cattle. ld .. Res. Bul. 436, 1949. Ragsdale, A. c., W.orstell, D. 1\1.. Thompson, H. J., and Brody,S., Influence of temperature, 50° to O°F. and 50° to 95°F., on milk production. feed and water consumption and body weight in Jersey and Holstein cows. ld., Res. Bul. 449, 1949.

I�Thomp90n, H. J., l\lcCroske)', R. M., nnd Brody,S., Influence of nmbient temperature, 0° to 105°F., on insensible weight loss and moisture vaporization in Holstein and Jersey cattle. Univ. Missouri Agr. Exp. Sta. Res. Bul. 451, 1949.

TABLE 1. TEMPERATURE CALENDAR

Summer 1948 Temperature Relative

Level of. Humidity, % From To Exper. Control Exper. Control (& including)

50.5 50.5 62 67 March 6· April 15 60 50.5 63 69 April 16 May 2 69.5 50.5 65 69 May 3 lune 8 80 53 65 71 lune 9 June 23 85 55.5 68 73 June 24 July 7 90 57 68 76 July 8 July 21 94.5 57 63 72 July 22 July 31 99 53 58 72 August 1 August 5

105 52 56 70 August 6 August 6 (7 hrs.)

decreased increased 68 72 August 7 August 12 to 701 to 701

60 increased 70 65 August 13 August 20 to 1001

64 decreased 75 73 August 21 August 26 to 601

Winter 1948 49 -Temperature Relative

Level of. Humidity, % From To Exper. Control Exper. Control (& Including)

52 53 71 69 Oct. 25- Nov. 7 41 50 65 60 Nov. 8 Nov. 21 32 50 70 63 Nov. 22 Dec. 5 23 50 79 66 Dec. 6 Dec. 19 12 49 85 61 Dec. 20 Jan. 2

8.5 49 88 55 Jan. 3 Jan. 9 Power failure �� Temp. control 85 67 Jan. 10 Jan. 16

(7 - 45!) (500:) 5 50 83 53 Ian. 17 Jan. 23

increased decreased to 50* to 5* 53 65 Jan. 24 Jan. 30 50 4 58 77 Jan. 31 Feb. 13

increased 50 to 501 65 69 Feb. 14 Feb. 20 50 50 60 69 Feb. 21 Feb. 27 65 50 65 60 Feb. 28 March 6 69 50 68 61 March 7 March 13 74 50.5 60 55 March 14 March 20 80 50.5 58 64 March 21 March 27 84 51 60 64 March 28· March 29 90 51 60 65 March 30 March 31 94.5 50 46 64 April 1 April 2 70 50 60 63 April 3 60 56 60 65 April 4

·Up to and including March 21, 1949, the temperature changes were made in the mornings (about 8:00 a.m.); after March 21, the changes were made in the afternoon (3:00-4:00 p.m.) before the dates shown.

#Increased or decreased by 5 or 1 OOF . temperature intervals.

'""' .. �


there were no consistent differences in the temperature of these six spots under the given conditions, they were averaged for each cow and plotted ngajns� the average of nine air temperatures taken in each perpendicular plane of the right·hand stall partition at the 1.5, 4.5· and 7.5·foot levels in the liller alley, the stall, and the feed alley; and against the average of eight radiometer chamber surface temperature measurements taken at the intersections of this plane and chamber surfaces. Six 200-w8t1 incandescent light bulbs in each chamber at the 9·(00t, or ceiling, level were on during the measurement periods.

The numerical data, averaged for each breed, are given in Table 2. Figure 4 presents the average skin and hair temperatures for each cow. Figure 5 brings out the relation between skin and hair temperatures in more definite form. In the lower segment the fitted curves (equalions shown in Table 2) of the data for hair temperature (by touch thermocouple and radiometer) or

IOOr-----�----+-----+_----+_�

90

"" 70r-1f---��--W'------+- "'f--+-----H---�.>..f---+_----+_1 ::J '< "" � �

� 60J---�7F_-_t_-- WINTEt 1946·49 H-14

-----H--r--- SUMMER 1946 _-II H-lo6 000 __ H-1I8

..... .-« �-� �_4 --,........

H-I09 H· 1)6 J - 9)) J -j06

--.. H-8) _ J-994

J- )02

__ ---j • ---1--- ""'" J ·202 r It-----<< J-212

TOUCH THERMOCOUPlE MEASUREMENTS

400��20��-4�O��60��-8�O�� 607-��80��I�OO AIR TEMPERATURE:F.

Fig. 4.--Individllal skin and hair surface temperatures plotle-d against environmental temptrature. The lower Ihe environmental tcmperatUle. the �!:1eater the individual and breed differences in sulface temperature.

10 MISSOURI ACRICULTURAL EXPERIMENT STATION

90'1----+---" /

/ / �.80'ro----71�/�----t_--��r_----�------_+--� � ,.''/

/

� � � 7Ot----t---� t-

6

500��-40��60��80��oo� AI� TEMPE�ATU�E. oF. (TOLCH TH(lMCXOJlUI

Fig. 5.-Average !:nIrraCe and skin temperature plotted against air temperature (lower segment); several categories of tempcru!ure differences similarly plotted against ambient ternperaturc. See Tables 3 and 4 for the equations (fitted by the method of least squares). The heavy curves represent touch thermocouple measurements; the light curves Hnrdy radiometer data. Breaks in curves with change in slope seem to occur at about 65°F .• apparently a zone of "critical tempcruturc" for these cattle. Note the temperature-regulating function of the hair (temperature differences bt"tween skin, hair. and air at the lower ambient temperatures), and the crossing of the curves between 1000 and lOsoF., ambient temperaturt.

"� .. "


hoth breeds are compared to the skin temperatures of the Jerseys (solid curve) and the Holsteins (hroken curve). In the upper segment the temperature differences between skin, hair, and air are shown (equations for the curves are given in Table 3). At about O°F. ambient temperature the temperature

Date of Measurements

Apr1l15, 1948 50.9· 80.3 91.3 50.9* '19.1 89.2 Aprll 26 60.5· 82.6 91.3 62.'1 8'1.0 60.5* 83.5 89.'1 61.9 8'1.3 May '1, 14, 24 &) 68.8 88.6 94.'1 '10.0 90.2 6'1.9 88.3 93.6 69.6 90.3

lune 3 ) lune 11, 15, 23 '18.9 92.5 96.0 79.0 lune 25, 29 &)

92.3 78.4 93.1 96.4 '19.8 93.4

luly 2, 7 ) 84.7 93.9 96.5 84.6 95.6 84.3 93.9 96.5 84.5 96.0 luly 9, 13, 17, 20 89.7 96.3 98.6 89.4 96.6 89.6 96.0 98.1 89.2 96.9 luly 23,26,30 94.1 98.3 99.9 93.0 98.0 94.1 98.1 99.8 93.0 98.5 August 2,5 99.4 100.7 101.8 97.2 100.1 99.8 100.4 101.1 97.1 100.1 August 6 102.9 103.0 102..7 102.5 102.7 103.0 102.4 102.8 102.1 103.1 August 10 80.4 92.3 95.5 81.8 93.6 80.2 93.0 95.6 81.4 94.8 August 23 63.8 87.9 92.5 64.2 88.4 63.3 86.9 90.8 64.1 89.2

49.5*' � Cows (March.!!2 August � !M§)

Aprll 21, 1948 77.1 87.7 55.2 78.4 Apr1l26 50.6· 79.2 88.3 53.2 81.4 May 10 51.8 77.5 86.1 53.6 80.4 51.9 '1'1.2 86.0 53.7 81.8 lune4 50.5 77.1 84.4 56.2 84.2 50.5 80.2 85.6 55.4 83.8 lune 16 51.6 81.4 88.3 54.4 82.1 52.1 82.3 86.8 53.8 82.3 luly 8 59.1 82.4 87.3 61.5 86.3 58.6 84.7 89.6 60.7 88.3 August 9 58.7 84.1 91.6 61.8 85.9 57.8 84.3 91.5 61.6 8'1.6 August 1'1 85.5 96.9 99.4 95.9 85.4 96.4 99.0 85.4 95.6 August 19 91.5 98.1 100.9 91.0 98.2 90.9 9'1.8 99.6 90.6 98.0 August 20 94.'1 99.2 100.'1 93.'1 99.2 94.'1 99.1 100.6 93.9 99.3 August 21 99.9 101.3 102.0 98.4. 101.1 99.'1 100.2 100.'1 98.2 100.1

Experimental Cows (oct.� 1948, �� 4 1949) Nov. 1, 1948 58.3 82.6 91.'1 59.5 82.3 5'1.3 82.4 93.2 59.3 84.6 Nov. 5 52.'1 '18.4 89.2 54.6 80.0 51.3 '1'1.5 90.1 53.9 '19.9 Nov. 10 43.8 '13.5 8'1.8 4'1.'1 '16.8 40.4 71.5 8'1.4 42.9 '73.8 Nov. 30 31.1 64.9 83.8 36.0 69.1 29.4 66.4 87.1 33.8 68.1 Dec. 9 20.3 59.3 80.9 25.9 64.5 1'1.3 53.3 84.3 25.6 60.6 Dec. 23 13.5· 18.4 55.9 13.5· 16.2 58.5 Ian. 17, 1949 '1.5 48.2 '13.'1 11.'1 52.0 5.2 51.3 80.6 10.6 51.9 Ian. 20 3.2· " 50.6 76.8 54.3 3.2* 52.6 80.3 52.8 Feb. 11 52.3 '18.9 86.8 52.5 80.3 89.9 Feb. 25 51.4 '16.8 90.6 55.1 '18.8 51.8 '18.2 91.0 54.2 80.1 March 21 '15.'1 90.3 96.4 '1'1.2 90.1 75.0 91.8 96.9 76.1 91.9 March 29 85.2 94.6 98.1 86.2 94.6 84.5 95.'1 98.6 85.3 95.2 March 31 90.3 96.'1 99.4 89.3 95.9 89.9 97.0 99.4 88.8 00.9 Apr1l2 95.4 98.9 99.9 95.0 98.'1 95.4 BB.6 99.8 94.9 98.6 Apr1l4 61.6 84.4 91.4 64.3 84.6 60.8 83.6 90.7 63.5 86.4

Control Cows (Oct. � 1948, to Aprll.!, 1949) 81.6 89.3 56.0 82.3 52.1 81.3 90.4 55.0 81.3 68.8 84.'1 41.3 '13.4 36.9 6'1.5 83.3 39.5 '11.4 59.3 81.6 23.9 63.4 19.0· 58.4 .81.3 22.'1 64.2 50.2 77.1 12.'1 59.4 5.9 50.9 '15.4 10.4 59.4 50.'1 '16.2 2.9· 51.'1 '14.3 80.8 90.0 53.9 50.3 81.5 90.'1 52.3 84.6

Y


TABLE 3. EQUATIONS RELATING SURFACE TEMPERATURE (V) TO CHAMBER AIR TEMPERATURE (X)

(Curves given in lower section of Fig. 5)

Y Test Period

Skin Temperature Winter 1948-6 (touch thermocouple)

Winter 1948-9

Hair Temperature (touch thermocouple) Winter 1948-9

Hair Temperature (radJometer)

Skin Temperature (touch thermocouple)

. . . . . . Hair Temperature

(touch thermocouple)

Hair Temperature (radiometer)

-Not shown in Fig. 5.

Winter 1948-9

Winter 1948-9

Winter 1948-9

Summer 1948 Summer 1948

Winter 1948-9 Winter 1948-9


'Wlnter 1948-9 -Winter 1948-9


Winter 1948-9 Winter 1948-9

. .

00 to 6S

or.

Holstein

1ersey

Holstein

Jersey

Holstein

Jersey

6 to

Holstein Jersey

HolsteIn Jersey

Holstein Jersey

Holstein Jersey . . . . Holstein Jersey

Holstein Jersey

30

30

30

30

30

30

63 63

12 12

66 66

12 12

65 66

12 12

E uatlon = surface temp.,

X=air tern OF

Y=74.3 ... 286X

Y=80.1 ... 199X . .

Y=46.3 ... 613X

Y:::4a.O+ .589X

Y=50.7 •. 5S7X

Y= 50.3+ .584X

Y",78.3+.227X Y,,77.3+.236X

Y=82.6+.183X Y,,86.2+ .145X

Y,,61.1+.395X Y ,,63.1 + .372X

Y"S7.2+.438X Y,,87.4+.330X . . . . . Y=66.5+ .338X y" 68.3 + .323X

Y" 58.1 + .424X Y=67.S+,327X

F

. .

,930

.905

,987

.961

.971

.984

.911

.928

.948

.962 . .

.964

.966

.978

.983

.947

.969

.974

.962

tan ar Error of Estimate

2.38

1.99

2.10

3.62

'2:98 2.29

1.03 0,98

0,49 0.34

1.12 1.07

0.75 0.76

1.17 0.88

0.79 0.77

difference between .skin and air was about 75°F.; between hair and air, about

45°F.; between hair and skin, 30°F. All these body. surface temperatures

merge between environmental temperatures 100° and lOSeF., which is vir·

tually the upper temperature limit that these European·e\·olved cattle could

withstand for one day. The rectal temperature,t which is normally 101°F.

in cows, reached 106° to lOB.SoF, at environmental temperature 10soF. The

two pregnant "control" ( unaccl imatized) Holstein cows aborted on exposin;,;

them to ]OO°F. for 27 hours,'1 apparently a con�equence of the heat stress,

The higher skin-but not hair-temperature at low ambient temperature in

the Jerseys lhan in the Holsteins may be due to: (l) higher rale of heat pro·

duction (per unit weight) in the (small) Jerseys; (2) thinner and leaner

skin with higher heat conductance in the Jerseys; (3) surface temperature in


the smaller Jerseys is nearer to the internal temperature than in the larger Holstein5; (4) higher insulating properties of the hair of Holsteins.

TABLE 4. EQUATIONS RELATING THE DIFFERENCE BETWEEN SURFACE TEMPERATURE AND AIR TEMPERATURE (Y) TO CHAMBER AIR TEMPERATURE (X)

(Curves given in upper section of Fig. 5)

Y

Skin T. less Air T. (touch thermocouple)

. . . · . · . .

Hai.r T. less Air T. (touch thermocouple)

· . . · . · . . .

Hair T. less Chamber Surface T.

(radlometer) · . · . .

Skin T. less Hair T. (touch thermocouple)

· . · . · . · . . . . .

Skin T. less Air T. (touch thermocouple)

· . . . . . . . . .

Hair T. less Air T. (touch thermocouple)

· . · . . · . . .

Ba.lr T. less Chamber

· .

Surface T. (radiometer)

· . . . · .

Skin T. less Hair T. (touch thermocouple)

Winter 1946-9

Winter 1948-9 . . . . .

Winter 1946-9

Winter 1946-9 · . . . · . .

Winter 1948-9

Winter 1948-9 . . ..

Winter 1946-9

Winter 1948-9 · . . . . · .


·Wlnter 1946-9 ·Wlnter 1948-9 · . . . .


·Wlnter 1948-9 ·Winter 1948-9 · . . . .


·Wlnter 1948-9 • Winter 1948-9 · . . . · .


*Wlnter 1948-9 *Wlnter 1948-9

*Not shown In Fig. 5 . •

u. on Y - temp. dUe. 0 F. X=air tern . F.

00 to 650F.

Holstein

Jersey

Holstein

Jersey

Holstein

Jersey

Holstein

Jersey

Holstein Jersey

Holstein Jersey

. . .

Holstein Jersey

Holstein Jersey

. . .

Holstein Iersey

Holstein Jersey

0

3.

3.

3.

3.

27

27

3.

3.

63 63

12 12 . .

66 66

I' I'

. .

65 66

I' I'

. . . . . .

Holstein 63 Jersey 63

Holstein I' Jersey I'

Y=73.6 - .698X

Y '" 79.4 - .767X . . . .

Y = 45.6 - .372X

Y::47.2 - .397X . . . .

Y = 43.9 - .365X

Y"" 43.9 - .344X . . . . . .

Y=26.0-.327X

Y:: 32.2 - .39OX . . . . . .

Y::78.3 - .773X Y::77.2 - .763X

Y:82.6 - .817X Y::86.2 - .651X

. . . . . . . .

Y" 61.1 - .60s}( Y::63.1- .628X

Y=57.2-.562.X Y::67.4 - .670X . . . . . .

Y=59.2 - .57tx Y = 58.2 -.559X

Y=47.7 - .459X Y = 58.4 - .569X

. . . .

Y::17.0-.166X Y=13. 9 - .132X

Y:: 25.4 - .254X Y:: 16.8 - .185X

..

. .

.966

.992

.971

.924

.935

.913

.955

.934

.913 .991

.997

.999 . . . .

.984 .988

.986

.991

. .

.973

.976

.989

.960 . .

.867

.894

.973 .920

Stan , Error of Estimate

. . .

2.30

2.08

1.92

3.50

2.75

3.12

2.14

3.18

1.03 1.06

0.49 0.34 . .

1.12 1.07

0.75 0.76 . .

1.39 1.27

0.56 0.96 . .

..96 0.69

0.46 0.65

. .

. .

. .


Figure 6 presents the individual data points together with their fitted equations (Table 3) from which the curves were drawn in Figure 5.

1I(y-----r--,----,-----,----,·---,-----.---,------;-----,-,--, 1'0

00

90

80

70 \tMoll WllIT{t ,,.. ,., 6Ot·

'" ::0 e-

50 :2 � � 40 e-

.,. "0 JO oil

I 06 tlC'N T1.ttlUAtUl( ,"" 20

• Idi '" .. l <Xl 10 00

"''''IIOIT All lIIt"lA'lUtl "t. 1I!lUIOCOU'U

0

"

Fig. 6.-lndividual data points for skin temperature measured with the touch thermo· couple Oeft �ection); hair surface and chamber surface temperature mea�ured with the Hardy radiometer {middle section}; hair surface measured with thermocouple (ri!!:ht section), all plotted against environmcr.tal nir temperature (measured with touch thermocouple). Each point represfJllts an average of six spot measurements. Data on rectal temperatures (by Kibler1) are shown in the insert for comparison. See Figure 5 and Tables 3 and 4 for the equations of the curves.

A VENUES OF HEAT-LOSS AND THE APPLICATION OF NEWTON'S LAW OF COOLING

Heat dissipation may be divided into two categories, evaporative and nonevaporative.

The evaporative category of ('ooling, at any rate cooling from sweat,13, 11

is under physiological (homeothermic) control. The higher the environmental temperature, the mOTe sweat is produced within the inherited limits of the

UKuno, Y. The physiology of human perspiration. London, 1934. Weiner, J. S., "The regional distribution of sweating." J. Physio!., 104, 32, 1945.

uHancock, W., Haldane, J. J., "The osmotic passage of water and gases through the human skin." Pr.oc. Royal Soc., 1118, 412, 1932. Pinson, E. A., "Evaporation Irom the human skin with sweat glands inactivated." Am. J. PhY'iiol., 109, 515, 1934.

-


species and individual, ar.d Ihe greater the evaporative cooling (if the levels of atmospheric humidity and convectivity permit).

The non·evaporative category of cooling (by radiation, convection, and conduction) is, on the other hand, under physical control and should be repre· sentable by the physical laws of cooling. There are several physical laws of cooling, including that of Stefan·Boltzman-Lambert for radiation, and Fourier for conduction. Under the present relatively narrow temperature limits, how- ( ever, Newton's Law as represented by equation (2) below, should be a sufficiently good approximation to the overall non·evaporative heat transfer.

To test the applicability of Newton's Law, the non-evaporative cooling values were computed by deducting from the total heat production I the evaporative heat lossesl2 as given by the equation:

H - Hv = He + Hr + Hd .. (1) in which H is total heat productiol1,l equal to total heat dissipation after the body temperature is stabilized; Hv is heai dissipation by vaporization jl2 and (H - Hv) is therefore, non-evaporative cooling which equals the sum of the heat losses by convection, HCj radiation, Hr; and conduction, Hd.

Newton's Law states that the non·evaporative heat loss, H - Nv, in lime, t, from a body of surface area, A, is directly proportional to the temperature difference, t1 - t2, between the surface and environment as given by the equation

H - Hv = kA (t, - t,)t ....... (2) in \9hich k is the coefficient of heat transfer defined by the equation, and determined by experiment, its numerical value depending on the units employed, here in Callm'/ltrll OF.

With this introduction we may apply equation (2) to the non-evaporative data on heat dissipation_

The basic idea in equation (2) is that the rate of heat loss is directly proportional to the temperature difference between body surface and environment. Hence, in Figure 7 the lower scale represents temperature gradient, or difference. t1 - t2; the upper scale, however, represents, for purpos('s of orientation, estimates of the absolute ambient air temperatures. The symbols and heavy lines represent the data ploued against the gradient between hair-coat sur/ace (measured by the Hardy radiometer) and environmental air temperatUTe (measured with touch thermocouple). The light broken lines represent the fitted curve, without data, plotted against the difference between the skin surface temperature and air temperature, both measured with the touch thermocouple. The fitted curves to the non-evaporative data in the bottom segment, are linear and virtually pass through the 0,0 point. It is, therefore, concluded that Newton's Law of Cooling is, broadly speaking, applicable to the nonevaporative cooling of these cows under the given conditions (temperature of air, walls, ceiling, and floor were virtually the �ame).

1 6 MISSOURI AGRICULTURAL EXPERIMENT STATION

AI'PIOXMAT[ AIR HMPlRA TURE:F. KJ. HAI.-.AJ� ( 00 90 &0 � 60 1" <40 ):l � 10 } �u FCt SllN-Ml � 0 115E� DO ' "

"",ST"NS �t-;:; o· r .. �� - 90.2-U'2ISKlH-A.I. T.' < �� ( -;lOW. tf..I>l .... ·.49 s.,.·'1'2.6

'iii '« �....,- _ 1 --r !< � . ' "'fO"IA["ll; .'1. '.82 s.....14.78

Q 1° :. � - - w. .m-.&S.lOVUl-t'Jl T.I � 4 - -- 4)J-.';02(Sl:IH-All TJ -

� � ''',2''''''''''Nl T. �('"T.. � , � lOrJ"'H{AT' A',66 '"" 1"')

� I ' ..(.',41 s.,.oIl'2.S 1 ,\0 : . 0 - - - - - _ _ _ I ' � I .. _ .. t� _.0 -, --..-.... T---t� ��.==��==�==� 1 �

• • •

12 .", .6 /EW"1I4'.8)OISJ:lIh\1l tJ --I-

8��'��-=� - - :-

.

,.. ,.. .. "'1 1 .816UWl-A11 1.)") --.- ---

i 4 _ � 11-' � S",,·:7.0'2 (VAP-S8.7-56'25KIH-A1l T) tpJt •• �1(N.� �'!I6J E',,·,e-e.,.7-.998iH.Alk-All1.1

(I,,:. D • T ... "1J-_i "... 8) >"":6..40

I �, '�I i---l---I

.p>f;,if. ., ./ /' l """ ' ,/"/ I:i:..J � 1 ,�.. :; . ""' 1 ' /' .

� , ./ � R __ � �·EW-"9.6a''2.4'2(S(JN-All T.) § o . �"� >".1�6 U ....... ""- U

� �-EW"04.82-).6""""-Al T.I 2

i 4

'

�.". s..·,20,' .,'''' ..... '1' J[l�Y1 0 i , .�- , � 5l.NMU 19<48 I" lEl5EYS Q � " IO.ST[1NS ,

10 10 30 10 50 60 70 HMPlRATUR[ GRADI[NT, 'F.

HAIR IlAQ) OR SKIN no SUPJ,ACE lESS AIR 1.

.'

Fig. 7.-Comparison of the non-evaporative (lower segment) and evaporative cooling': (middle and upper segments) curves plotted against temperature gradient- defined here by .. the rliffert!llc(' between body surface and ambient temperature, The heavy curves and symbols represent cooling as function of temperature difference between hair surface (measured with radiometer) and nir (measured with touch thermocouple>. The light broken lines (data not shown) reprt'.senls cooling as function of temperature difference between skin surface and air (measurcd with touch thermocouple), The light continuous line for heat production' is shown lor comparative purposes. Data on non-evaporative cooling is the difference between heat pro-duction and evaporative cl)oling. The "r" values for the curves on evaporative cooling (center section) are not significant (N.S.) for the curve in which (hair - air T) is ordinate but sig-nificant (*) for ordinate (!lkin _ air T). All other ,'alues of <lr" are highly significant. Tables from "Statistical Methods:' G. W. Snedecor, 1946, were used for the tests of significance of these curves. The approximate air temperature scales for the hair-Iess·air-temperature differ-ence curves (same for Holstein and Jersey) and for the skin·less-air-temperature difference cunes (SIlme for Jersey and Holstein above 40°F.) are given at the top of the chart

RESEARCH BULLETIN 48 1 1 7

The total hent production1 (light continuous curve) i s also given i n the bottom segment of rigure 7. The curves of non-evaporative cooling and of total heat production get closer together with increasing temperature gradient (or decreasing ambient temperature) ; that is, as the ambient temperature is lowered, the rate of evaporative cooling is also lowered and the rale of nonevaporative cooling ( radiation, convection, conduction) is increased.

The evaporative cooling curves are also shown in Figure 7. While the non-evaporative cooling curves (bottom segment, Figure 7) are linearly continuous-as would be expected from Newton's Law of Cooling-the evaporative curves (middle and top segment, Figure 7) are discontinuous, showing breaks, or more correctly, sharp changes in slope, at 22°F. hair-air temperature difference or about 65°F. environmental temperature. The "breaks" in the curves are evidently exaggerated (the curves represent least squares fits of linear equations to the rather labile high-temperature data) ' and so overdramatize the basic difference in the nature and shape of the non-evaporativc and evaporative cooling curves as functions of temperature gradient between animal and environment j but there is no question about the presence of .1.

sharp change in slope at about 65°F. environmental temperature, and this is the important difference between the shape of the non-evaporative and evaporative cooling curves as functions of temperature gradient.

Ii mny be notcd that similar ':breaks" at the same temperature were ob· served when respiration rate, rectal temperature, and most other physiological reactions, were plotted against temperature differences between body and environment. They are all correlative phenomenon. Each of these reactions tells the same �tory in a somewhat different dialect.

18 MISSOURI AGRICULTURAL EXPER1ME�T STATION

SUMMARY AND ABSTRACT

Data are presented in tabular and graphic forms on the effect of ambient temperatures, 0" to 105 "F., on skill and hair temperatures of lactating Holstein and Jersey cows.

The temperatures of skin, ha.ir, and air are widely apart at O°F. ( about 75"F. difference between skin and air temperature, and about 4,5"F. difference between hair and air temperatures) and merge at lOa" to l05"F.

ambient temperature. At O°F. ambient temperature, the hair surface tern· perature is aboul 50°F'. in both Jcr!'cys and Holsteins; the skin temperature is about BO°F. in Jerseys and 75"F. in Holsteins with rather wide individual differences; at l03'F. ambient temperature the temperatures of skin and hair are also 103°F'.

The heat dissipated from the surfaces to the environment was partitioned between the non-evaporative and evaporative categories of cooling and the resulting values plotted against the temperature difference or gradient, t\ - t�, between body surface 3nd environment.

The rale of non-evaporative cooling (sum of convective, radiative) and conductive cooling) follows Newton's Law of Cooling; the data points are distributed linearly and pass through 0_0 when plotted against the temperature gradient, tl - t2•

The rate of evaporative cooling (as also heat production, res.piration rate, and rectal temperature) when ploued against the temperature gradient between body-surfllce and environment �how breaks 2.t aboul 22°F_ gradient, corresponding to an ambient temperature of about 65°r_ The ambient temperature of about 65°F. is, in this Foense, a "critical temperature" for these catt le; it correo;;ponds to the beginning of the decline in acceleration in the cun'e of the ralio of evaporative cool ing to heat production with increasing environmental temperaturcl � and, conscquenliy, with the beginning of the rise in rectal temperat1lre and respiration rate, and with the decline in feed consumption. milk production, and related reactions.

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Environmental Physiology - Division Of Animal Sciences - University