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A System for Diurnal Heart Rate Measurement in Chickens1
A System for Diurnal Heart Rate Measurement in Chickens1 J. R. CAIN AND U. K. ABBOTT Department of Avian Sciences, University of California, Davis, California 95616 (Received for publication February 14, 1970)
A
VARIETY of methods have been used to measure the heart rate of chickens and commonly heart rate has been altered by the measurement process. In general birds have been placed in an unfamiliar environment either restrained or anesthetized. Time of day, comfort of the bird or activity of the investigator have often been contributing factors to the heart rate obtained. We wished to develop a system permitting the heart measurement and comparison of a large number of birds under essentially normal conditions. Such a system would allow valid comparisons of breeds, sexes and ages, any of which may react differently to handling. In this report a measurement system developed to satisfy these criteria and its application is described. APPARATUS A scanning device was developed to automatically survey the electrocardiograms (EKG) of twenty chickens each hour. The multiplexing unit scanned stations, without switching transients to the pen recorder, by moving a beam of light past a series of photo-sensitive diodes; high resistance paths in the dark, low in the presence of light. Forty photocells were arranged in two concentric circles and recessed into opaque black plexiglass. A light-tight disc with a small slit covered the photodiodes (Fig. 1). Two legs of each pair of photocells were attached to the two leads from 1
Supported in part by NIH Grant H2S66.
the bird and also connected to ground across a 100K ohm resistor to reduce 60 Hertz interference. The other legs of the photodiodes were connected in common to the input of the recorder (Fig. 2). The photocells were fifteen inches from the 115 v AC circuit to reduce electrostatic interference from the light source. A synchronous motor coupled with a microswitch supplied the current to a stepping relay which rotated the light slit in the disc from one pair of photocells to the next every IS seconds. A one rph motor and microswitch initiated this 5 minute cycle once hourly. During the balance of time, the light source, recorder paper drive and four rpm motor were turned off by a DPDT relay (Fig. 3). The recording electrodes were # 1 stainless steel safety pins placed in a lead II position (base of right wing and left leg) with the ground electrode under the skin of the uropygium. The electrode lead-off wires were 25 gauge insulated stranded wire led through the pivot point of the pin and soldered at the head of the pin. The electrode lead-off wires were clamped to the middle of the back with Mitchell wound clips to prevent electrode movement. The three lead-offs were braided together and just long enough to enable the bird to squat down in any part of its cage. Slip ring bearings (Model #1301, Fabricast Inc., So. El Monte, Calif.) were mounted on top of each cage to prevent twisting of the electrode wires (Fig. 4). The three terminals of each stationary brush block were connected by shielded ca-
1085
Downloaded from http://ps.oxfordjournals.org/ at National Institute of Education Library, Serials Unit on April 25, 2015
INTRODUCTION
1. 2. 3. 4. 5. 6.
NEEDLE BEARING 3/4 I.D., 1 1/2 O.D. COLLAR 3/V'l.D., 9/16"W. SOLENOID 115 AC, I. 110 OZ. 20 POS. RACHET 3/8"l.D., 1 1/4"O.D. PILLOW BLOCK 3/4"HOLE l" PHENOLIC ROD
Note: Material net indicated is black phenolic plaeti opaque
FIG. 1. A specification drawing of the multiplexing unit.
To bird #3
UD
¥^
To Recorder Pre-amp ^ -
DO
A-^>-
All resistors 100K ohms
rF~
All diodes RCA 4402
To bird # 13
€
333
^-o-
fF MULTIPLEXING UNIT - MILLIVOLTAGE CIRCUIT
FIG. 2. A wiring diagram of the millivoltage circuit of the multiplexing unit.
Downloaded from http://ps.oxfordjournals.org/ at National Institute of Education Library, Serials Unit on April 25, 2015
MULTIPLEXING UNIT
HEART RATE MEASUREMENTS
1087
Fic. 3. A wiring diagram of the 1 IS v AC circuit of the multiplexing unit.
ble to the scanning unit. The slip rings were attached to the electrode leads and rotated freely as the bird turned around in its cage. The equipment, birds and cages had a common ground (Fig. 5). PROCEDURE
The diurnal heart rate rhythm of twenty Single Comb White Leghorns (S.C.W.L.) was determined. These included equal numbers of males and females of two age groups; eight were 30 and twelve were six months of age. They were housed randomly
FIG. 4. Slip ring and brush block assembly used to prevent twisting of electrode lead-off wires.
FIG. 5. Block diagram of equipment used to automatically monitor avian heart rates.
in individual cages at one end of a laying house, but were not isolated from the rest of the house. The birds received 14 hours of light and 10 of dark. Lights were switched on at 6:00 A.M. No one was permitted into the recording area fifteen minutes prior to or during the monitoring period. Electrocardiograms (EKG's) were recorded with an Offner model RS Dynograph* for each bird every hour for fortyeight consecutive hours. Heart rate was determined as an average of two records for each hour on two consecutive days. A second group of birds (from a line of miscellaneous origin) was measured under restrained and nonrestrained conditions. The heart rate of ten males and ten females was sampled periodically throughout the day by the previously described nonre* Beckman Instruments, Inc., Spinco Division, Palo Alto, Calif.
Downloaded from http://ps.oxfordjournals.org/ at National Institute of Education Library, Serials Unit on April 25, 2015
MULTIPLEXING UNIT - 115V AC CIRCUIT
1088
J. R. CAIN AND U. K. ABBOTT
_l_
L.
FIG. 6. Diurnal heart rates of 6 month and 30 month old Single Comb White Leghorn chickens.
strained procedures. Subsequently the birds were brought into an adjacent laboratory, restrained on a V-board and when quiet their heart rates were measured again. RESULTS A 24 hour rhythm in heart rate was apparent in both sexes, but was most striking in the older (30 month) females (Fig. 6). In both groups the most rapid rates were recorded in the early morning hours just after the lights came on. Heart rates usually decreased slightly during the balance of the light period. At the onset of the dark period there was an abrupt decrease, especially in older birds. The old males had consistently slower heart rates than the young, while old females differed only slightly from young females. The highest heart rate recorded was 405 b.p.m. by a young female, while the lowest was 170 b.p.m. recorded for some males at night. Generally each bird had a heart
DISCUSSION Measurements of heart rate for domestic fowl have been reported by a large number of investigators. The rates given for adult cocks range for example from 199 b.p.m. (Smith et al, 1966) to 372 b.p.m. (Whittow et al., 1965). The wide range of measurement techniques probably accounts for most of the variation observed in the literature. Sturkie (1949) strapped the birds into a V-shaped holder and covered the birds with a cloth. Smith et al. (1966) determined heart rate aurally while the bird was held in the crook of the observer's arm. Rodbard and Tolpin (1949) rotated the animal at arm's length several times before placing it on a board with the head tucked under one wing. McNally (1941) used an electrocardiotachometer to measure heart rate. The birds were placed in a battery and the electrodes were suspended above allowing freedom of movement. Radio telemetry (Sturkie, 1963) seemed to allow measurement of heart rate under normal conditions, free of restraint and excitement. It was first reported the heart rates of individual unrestrained birds were neither higher nor lower than those of unanesthetized restrained chickens of the same breed and sex. Subsequently, however, Whittow et al. (1965) reported that heart rate, cardiac output and stroke volume of birds under restraint increase significantly. Telemetry, expensive and usually limited to recording one or few animals
Downloaded from http://ps.oxfordjournals.org/ at National Institute of Education Library, Serials Unit on April 25, 2015
rate pattern which was quite consistent from day to day. The mean heart rate of all recordings obtained from the unrestrained birds measured in the chicken house is compared with the mean heart rate from those birds measured in the laboratory under restraint in Table 1. The average "percent increase" in rate obtained by the restraint procedure was significant (P < .01).
1089
HEART RATE MEASUREMENTS TABLE 1.—Heart rates measured by restrained and non-restrained methods Wing Band
Non-restrained
Times
Average
9 15 11 15 8 11 11 15 11 11
5.1 4.0 6.1 3.4 6.5 7.7 4.1 3.0 9.7 3.8
180-140 200-140 200-140 210-160 210-160 230-140 230-190 240-190 270-160 250-200
11.7
191.2 + 6.3
% Greater
Ave. BPM + S.E.
Range (BPM)
4 4 3 4 6 4 5 5 6 4
310+12.8 260 + 7.9 323 + 16.5 282 + 13.0 328+11.6 292 + 7.4 268 + 5.2 326 + 3.6 317 + 4.5 335 + 4.3
340-280 280-240 260-290 320-250 340-320 310-270 280-250 340-320 330-300 350-330
95.0% 50.3% 86.3% 53.0% 76.9% 53.4% 33.8% 57.5% 52.4% 47.6%
227-159
4.9
304 + 8.7
335-260
59.8%
5.3 5.8 10.5 4.5 4.9 3.2 3.7 7.7 9.0 5.8
250-190 280-230 320-220 300-240 300-240 290-260 320-260 320-240 360-260 320-280
6 5 4 5 4 6 4 4 3 6
330 + 356 + 320 + 328 + 340 + 332 + 340 + 350 + 353 + 360 +
6.2 4.6 9.4 7.8 3.5 6.0 3.5 5.0 7.2 6.7
360-310 370-340 340-290 340-300 350-330 360-320 350-330 370-350 370-340 390-340
53.5% 36.4% 20.4% 20.1% 22.7% 19.4% 22.3% 29.0% 21.4% 20.4%
272.4 + 7.3
299-215
4.7
341.9 + 6.0
360-320
25.8%
159 + 173 + 175 + 185 + 186 + 191 + 201 + 207 + 208 + 227 +
Females 13468 13456 13114 12790 12323 12670 13453 12771 12796 12791 Average
11 11 9 15 11 9 15 11 11 8 11.1
215 + 261 + 269 + 273 + 277 ± 278 + 278 + 279 ± 295 + 299 +
at one time, could not conveniently be used in the kinds of comparisons desired here. This study provides an explanation for the differences that have been reported in the heart rate of chickens. Heart beat frequencies vary with the method of determination, time of day, sex, age, and other less tangible factors. Faster heart rates were obtained when the birds were restrained than when they were free to move about. Adult heart rate varied considerably even when the birds were recorded without restraint under normal cage house conditions. There seemed to be a slight decrease in heart rate with age among males, contrary to the findings of Muller and Carroll (1966). Females differed in this respect but appeared to be more responsive to diurnal changes in the environment. Other studies (Cain and Abbott, 1970) indicate the im-
portance of genetic differences and their interaction with the above factors. In view of these findings, it is apparent that the normal heart rate of domestic fowl is a variable quantity, and as such has little comparative value unless the specific conditions during measurement are considered. Measurements are probably most meaningful when made while the birds are free to move about in their normal surroundings. The apparatus and procedure developed in the course of this study provide such conditions. With the scanning unit, twenty birds could be monitored automatically at constant time intervals. The slipring bearings afforded the birds freedom of movement. This system permits us to make comparisons between groups of chickens with a minimum of recording variables between individuals.
Downloaded from http://ps.oxfordjournals.org/ at National Institute of Education Library, Serials Unit on April 25, 2015
Range (BPM)
Males Times Ave. BPM + S.E. 13220 13452 13459 13449 13476 13454 13451 13448 13218 13455
Restrained
1090
J. R. CAIN AND U. K. ABBOTT ACKNOWLEDGEMENT
A monitoring system was developed permitting heart rate measurement and comparison of a large number of birds under essentially normal conditions. Twenty chickens were monitored automatically at constant time intervals with a multiplexing unit that scanned stations without switching transients to the pen recorder. Slip-ring bearings mounted on the cages avoided twisting of the electrode leads. The diurnal heart rate rhythm of 20 Single Comb White Leghorns from two age groups was determined. Thirty month old male chickens had heart rates consistently slower than six month males. Old females exhibited greater diurnal heart rate fluctuations than young females. A second group of birds was measured under restrained and nonrestrained conditions. Restrained birds had significantly faster heart rates than did non-restrained chickens monitored with the system described here.
The authors appreciate the technical assistance of P. C. Backer in the construction of the multiplexing unit. REFERENCES Cain, J. R., and U. K. Abbott, 1970. Heart rate studies with scaleless chickens. Poultry Sci. In press. McNally, E. H., 1941. Heart rate of the domestic fowl. Poultry Sci. 20: 266-271. Muller, H. D., and M. E. Carroll, 1966. The relationships of blood pressure, heart rate and body weight to aging in the domestic fowl. Poultry Sci. 45: 1195-1198. Rodbard, S., and M. Tolpin, 1947, A relationship between temperature and the blood pressure in chickens. Am. J. Physiol. 151: 509-515. Smith, A. H., G. H. Bond and J. O. Nordstrom, 1966. Measurement of heart and respiratory frequencies in chickens. Poultry Sci. 45: 704708. Sturkie, P.D., 1949. The electrocardiogram of the chicken. Am. J. Vet. Res. 10: 168-175. Sturkie, P. D., 1963. Heart rate of chickens determined by radio telemetry during light and dark periods. Poultry Sci. 42: 797-798. Whittow, G. C , P. D. Sturkie and G. Stein, 1965. Cardiovascular changes in restrained chickens. Poultry Sci. 44: 1452-1459.
Hydrolyzed Leather Meal in Chick Diets1 BEN C. DILWORTH AND ELBERT J. DAY Poultry Science Department, Mississippi State University, State College, Mississippi 39762 (Received for publication February 14. 1970)
YDROLYZED leather meal2 (HLM) produced from tannery scraps was fed to broilers from 1-4 and 1-8 weeks of age by Hilliard and Waldroup (1969). These workers evaluated the nutritive value of HLM in broiler diets at dietary levels ranging from 1.0 to 8.0%. Methionine, lysine and tryptophane supplementation of the HLM
H
'Mississippi Agricultural Experiment Station Journal Article No. 1866. 'Proteenyte; Hynite Corporation, Oak Creek, Wisconsin.
diets was also studied. They concluded that dietary levels of HLM up to 8% could be satisfactorially used in nutritionally balanced broiler diets. HLM contains a minimum of 60% crude protein, a minimum of 5% crude fat and not more than 2.75% chromium. The primary source of the chromium in HLM is due to the various chrome chemicals used in tannery processes (O'Flaherty et al., 1962). The studies reported herein were under-
Downloaded from http://ps.oxfordjournals.org/ at National Institute of Education Library, Serials Unit on April 25, 2015
SUMMARY
A
VARIETY of methods have been used to measure the heart rate of chickens and commonly heart rate has been altered by the measurement process. In general birds have been placed in an unfamiliar environment either restrained or anesthetized. Time of day, comfort of the bird or activity of the investigator have often been contributing factors to the heart rate obtained. We wished to develop a system permitting the heart measurement and comparison of a large number of birds under essentially normal conditions. Such a system would allow valid comparisons of breeds, sexes and ages, any of which may react differently to handling. In this report a measurement system developed to satisfy these criteria and its application is described. APPARATUS A scanning device was developed to automatically survey the electrocardiograms (EKG) of twenty chickens each hour. The multiplexing unit scanned stations, without switching transients to the pen recorder, by moving a beam of light past a series of photo-sensitive diodes; high resistance paths in the dark, low in the presence of light. Forty photocells were arranged in two concentric circles and recessed into opaque black plexiglass. A light-tight disc with a small slit covered the photodiodes (Fig. 1). Two legs of each pair of photocells were attached to the two leads from 1
Supported in part by NIH Grant H2S66.
the bird and also connected to ground across a 100K ohm resistor to reduce 60 Hertz interference. The other legs of the photodiodes were connected in common to the input of the recorder (Fig. 2). The photocells were fifteen inches from the 115 v AC circuit to reduce electrostatic interference from the light source. A synchronous motor coupled with a microswitch supplied the current to a stepping relay which rotated the light slit in the disc from one pair of photocells to the next every IS seconds. A one rph motor and microswitch initiated this 5 minute cycle once hourly. During the balance of time, the light source, recorder paper drive and four rpm motor were turned off by a DPDT relay (Fig. 3). The recording electrodes were # 1 stainless steel safety pins placed in a lead II position (base of right wing and left leg) with the ground electrode under the skin of the uropygium. The electrode lead-off wires were 25 gauge insulated stranded wire led through the pivot point of the pin and soldered at the head of the pin. The electrode lead-off wires were clamped to the middle of the back with Mitchell wound clips to prevent electrode movement. The three lead-offs were braided together and just long enough to enable the bird to squat down in any part of its cage. Slip ring bearings (Model #1301, Fabricast Inc., So. El Monte, Calif.) were mounted on top of each cage to prevent twisting of the electrode wires (Fig. 4). The three terminals of each stationary brush block were connected by shielded ca-
1085
Downloaded from http://ps.oxfordjournals.org/ at National Institute of Education Library, Serials Unit on April 25, 2015
INTRODUCTION
1. 2. 3. 4. 5. 6.
NEEDLE BEARING 3/4 I.D., 1 1/2 O.D. COLLAR 3/V'l.D., 9/16"W. SOLENOID 115 AC, I. 110 OZ. 20 POS. RACHET 3/8"l.D., 1 1/4"O.D. PILLOW BLOCK 3/4"HOLE l" PHENOLIC ROD
Note: Material net indicated is black phenolic plaeti opaque
FIG. 1. A specification drawing of the multiplexing unit.
To bird #3
UD
¥^
To Recorder Pre-amp ^ -
DO
A-^>-
All resistors 100K ohms
rF~
All diodes RCA 4402
To bird # 13
€
333
^-o-
fF MULTIPLEXING UNIT - MILLIVOLTAGE CIRCUIT
FIG. 2. A wiring diagram of the millivoltage circuit of the multiplexing unit.
Downloaded from http://ps.oxfordjournals.org/ at National Institute of Education Library, Serials Unit on April 25, 2015
MULTIPLEXING UNIT
HEART RATE MEASUREMENTS
1087
Fic. 3. A wiring diagram of the 1 IS v AC circuit of the multiplexing unit.
ble to the scanning unit. The slip rings were attached to the electrode leads and rotated freely as the bird turned around in its cage. The equipment, birds and cages had a common ground (Fig. 5). PROCEDURE
The diurnal heart rate rhythm of twenty Single Comb White Leghorns (S.C.W.L.) was determined. These included equal numbers of males and females of two age groups; eight were 30 and twelve were six months of age. They were housed randomly
FIG. 4. Slip ring and brush block assembly used to prevent twisting of electrode lead-off wires.
FIG. 5. Block diagram of equipment used to automatically monitor avian heart rates.
in individual cages at one end of a laying house, but were not isolated from the rest of the house. The birds received 14 hours of light and 10 of dark. Lights were switched on at 6:00 A.M. No one was permitted into the recording area fifteen minutes prior to or during the monitoring period. Electrocardiograms (EKG's) were recorded with an Offner model RS Dynograph* for each bird every hour for fortyeight consecutive hours. Heart rate was determined as an average of two records for each hour on two consecutive days. A second group of birds (from a line of miscellaneous origin) was measured under restrained and nonrestrained conditions. The heart rate of ten males and ten females was sampled periodically throughout the day by the previously described nonre* Beckman Instruments, Inc., Spinco Division, Palo Alto, Calif.
Downloaded from http://ps.oxfordjournals.org/ at National Institute of Education Library, Serials Unit on April 25, 2015
MULTIPLEXING UNIT - 115V AC CIRCUIT
1088
J. R. CAIN AND U. K. ABBOTT
_l_
L.
FIG. 6. Diurnal heart rates of 6 month and 30 month old Single Comb White Leghorn chickens.
strained procedures. Subsequently the birds were brought into an adjacent laboratory, restrained on a V-board and when quiet their heart rates were measured again. RESULTS A 24 hour rhythm in heart rate was apparent in both sexes, but was most striking in the older (30 month) females (Fig. 6). In both groups the most rapid rates were recorded in the early morning hours just after the lights came on. Heart rates usually decreased slightly during the balance of the light period. At the onset of the dark period there was an abrupt decrease, especially in older birds. The old males had consistently slower heart rates than the young, while old females differed only slightly from young females. The highest heart rate recorded was 405 b.p.m. by a young female, while the lowest was 170 b.p.m. recorded for some males at night. Generally each bird had a heart
DISCUSSION Measurements of heart rate for domestic fowl have been reported by a large number of investigators. The rates given for adult cocks range for example from 199 b.p.m. (Smith et al, 1966) to 372 b.p.m. (Whittow et al., 1965). The wide range of measurement techniques probably accounts for most of the variation observed in the literature. Sturkie (1949) strapped the birds into a V-shaped holder and covered the birds with a cloth. Smith et al. (1966) determined heart rate aurally while the bird was held in the crook of the observer's arm. Rodbard and Tolpin (1949) rotated the animal at arm's length several times before placing it on a board with the head tucked under one wing. McNally (1941) used an electrocardiotachometer to measure heart rate. The birds were placed in a battery and the electrodes were suspended above allowing freedom of movement. Radio telemetry (Sturkie, 1963) seemed to allow measurement of heart rate under normal conditions, free of restraint and excitement. It was first reported the heart rates of individual unrestrained birds were neither higher nor lower than those of unanesthetized restrained chickens of the same breed and sex. Subsequently, however, Whittow et al. (1965) reported that heart rate, cardiac output and stroke volume of birds under restraint increase significantly. Telemetry, expensive and usually limited to recording one or few animals
Downloaded from http://ps.oxfordjournals.org/ at National Institute of Education Library, Serials Unit on April 25, 2015
rate pattern which was quite consistent from day to day. The mean heart rate of all recordings obtained from the unrestrained birds measured in the chicken house is compared with the mean heart rate from those birds measured in the laboratory under restraint in Table 1. The average "percent increase" in rate obtained by the restraint procedure was significant (P < .01).
1089
HEART RATE MEASUREMENTS TABLE 1.—Heart rates measured by restrained and non-restrained methods Wing Band
Non-restrained
Times
Average
9 15 11 15 8 11 11 15 11 11
5.1 4.0 6.1 3.4 6.5 7.7 4.1 3.0 9.7 3.8
180-140 200-140 200-140 210-160 210-160 230-140 230-190 240-190 270-160 250-200
11.7
191.2 + 6.3
% Greater
Ave. BPM + S.E.
Range (BPM)
4 4 3 4 6 4 5 5 6 4
310+12.8 260 + 7.9 323 + 16.5 282 + 13.0 328+11.6 292 + 7.4 268 + 5.2 326 + 3.6 317 + 4.5 335 + 4.3
340-280 280-240 260-290 320-250 340-320 310-270 280-250 340-320 330-300 350-330
95.0% 50.3% 86.3% 53.0% 76.9% 53.4% 33.8% 57.5% 52.4% 47.6%
227-159
4.9
304 + 8.7
335-260
59.8%
5.3 5.8 10.5 4.5 4.9 3.2 3.7 7.7 9.0 5.8
250-190 280-230 320-220 300-240 300-240 290-260 320-260 320-240 360-260 320-280
6 5 4 5 4 6 4 4 3 6
330 + 356 + 320 + 328 + 340 + 332 + 340 + 350 + 353 + 360 +
6.2 4.6 9.4 7.8 3.5 6.0 3.5 5.0 7.2 6.7
360-310 370-340 340-290 340-300 350-330 360-320 350-330 370-350 370-340 390-340
53.5% 36.4% 20.4% 20.1% 22.7% 19.4% 22.3% 29.0% 21.4% 20.4%
272.4 + 7.3
299-215
4.7
341.9 + 6.0
360-320
25.8%
159 + 173 + 175 + 185 + 186 + 191 + 201 + 207 + 208 + 227 +
Females 13468 13456 13114 12790 12323 12670 13453 12771 12796 12791 Average
11 11 9 15 11 9 15 11 11 8 11.1
215 + 261 + 269 + 273 + 277 ± 278 + 278 + 279 ± 295 + 299 +
at one time, could not conveniently be used in the kinds of comparisons desired here. This study provides an explanation for the differences that have been reported in the heart rate of chickens. Heart beat frequencies vary with the method of determination, time of day, sex, age, and other less tangible factors. Faster heart rates were obtained when the birds were restrained than when they were free to move about. Adult heart rate varied considerably even when the birds were recorded without restraint under normal cage house conditions. There seemed to be a slight decrease in heart rate with age among males, contrary to the findings of Muller and Carroll (1966). Females differed in this respect but appeared to be more responsive to diurnal changes in the environment. Other studies (Cain and Abbott, 1970) indicate the im-
portance of genetic differences and their interaction with the above factors. In view of these findings, it is apparent that the normal heart rate of domestic fowl is a variable quantity, and as such has little comparative value unless the specific conditions during measurement are considered. Measurements are probably most meaningful when made while the birds are free to move about in their normal surroundings. The apparatus and procedure developed in the course of this study provide such conditions. With the scanning unit, twenty birds could be monitored automatically at constant time intervals. The slipring bearings afforded the birds freedom of movement. This system permits us to make comparisons between groups of chickens with a minimum of recording variables between individuals.
Downloaded from http://ps.oxfordjournals.org/ at National Institute of Education Library, Serials Unit on April 25, 2015
Range (BPM)
Males Times Ave. BPM + S.E. 13220 13452 13459 13449 13476 13454 13451 13448 13218 13455
Restrained
1090
J. R. CAIN AND U. K. ABBOTT ACKNOWLEDGEMENT
A monitoring system was developed permitting heart rate measurement and comparison of a large number of birds under essentially normal conditions. Twenty chickens were monitored automatically at constant time intervals with a multiplexing unit that scanned stations without switching transients to the pen recorder. Slip-ring bearings mounted on the cages avoided twisting of the electrode leads. The diurnal heart rate rhythm of 20 Single Comb White Leghorns from two age groups was determined. Thirty month old male chickens had heart rates consistently slower than six month males. Old females exhibited greater diurnal heart rate fluctuations than young females. A second group of birds was measured under restrained and nonrestrained conditions. Restrained birds had significantly faster heart rates than did non-restrained chickens monitored with the system described here.
The authors appreciate the technical assistance of P. C. Backer in the construction of the multiplexing unit. REFERENCES Cain, J. R., and U. K. Abbott, 1970. Heart rate studies with scaleless chickens. Poultry Sci. In press. McNally, E. H., 1941. Heart rate of the domestic fowl. Poultry Sci. 20: 266-271. Muller, H. D., and M. E. Carroll, 1966. The relationships of blood pressure, heart rate and body weight to aging in the domestic fowl. Poultry Sci. 45: 1195-1198. Rodbard, S., and M. Tolpin, 1947, A relationship between temperature and the blood pressure in chickens. Am. J. Physiol. 151: 509-515. Smith, A. H., G. H. Bond and J. O. Nordstrom, 1966. Measurement of heart and respiratory frequencies in chickens. Poultry Sci. 45: 704708. Sturkie, P.D., 1949. The electrocardiogram of the chicken. Am. J. Vet. Res. 10: 168-175. Sturkie, P. D., 1963. Heart rate of chickens determined by radio telemetry during light and dark periods. Poultry Sci. 42: 797-798. Whittow, G. C , P. D. Sturkie and G. Stein, 1965. Cardiovascular changes in restrained chickens. Poultry Sci. 44: 1452-1459.
Hydrolyzed Leather Meal in Chick Diets1 BEN C. DILWORTH AND ELBERT J. DAY Poultry Science Department, Mississippi State University, State College, Mississippi 39762 (Received for publication February 14. 1970)
YDROLYZED leather meal2 (HLM) produced from tannery scraps was fed to broilers from 1-4 and 1-8 weeks of age by Hilliard and Waldroup (1969). These workers evaluated the nutritive value of HLM in broiler diets at dietary levels ranging from 1.0 to 8.0%. Methionine, lysine and tryptophane supplementation of the HLM
H
'Mississippi Agricultural Experiment Station Journal Article No. 1866. 'Proteenyte; Hynite Corporation, Oak Creek, Wisconsin.
diets was also studied. They concluded that dietary levels of HLM up to 8% could be satisfactorially used in nutritionally balanced broiler diets. HLM contains a minimum of 60% crude protein, a minimum of 5% crude fat and not more than 2.75% chromium. The primary source of the chromium in HLM is due to the various chrome chemicals used in tannery processes (O'Flaherty et al., 1962). The studies reported herein were under-
Downloaded from http://ps.oxfordjournals.org/ at National Institute of Education Library, Serials Unit on April 25, 2015
SUMMARY