Effect of Diet and Population Density on Male Turkeys Under Various Environmental Conditions. 1. Turkey Growth and Health Performance1 S. L. NOLL,2-3 M. E. EL HALAWANI,3 P. E. WAIBEL,3 P. REDIG,4 and K. JANNI5 Departments of Animal Science, Veterinary Biology, and Agricultural Engineering, University of Minnesota, St. Paul, Minnesota 55108 (Received for publication April 17, 1990)
1991 Poultry Science 70:923-934 INTRODUCTION
Performance of turkeys is affected by both nutrition and ambient environment. Temperature impacts performance primarily through its effect on feed consumption and subsequent BW gain, which decreases as temperature increases (National Research Council, NRC, 1981). However, minimum feed:gain ratios are reached at warm environmental temperatures. Therefore, the selection of rearing temperature is often influenced by relative feed to fuel cost (Waibel et al, 1976; Charles, 1989). In confinement buildings, ambient temperature alters the water-holding capacity of the air, which in turn affects litter moisture and
^Wished as Paper Number 18392, Scientific Journal Series, Minnesota Agricultural Experiment Station. T"o whom correspondence should be addressed. department of Animal Science. 4 Department of Veterinary Biology. Department of Agricultural Engineering.
dust and ammonia concentrations (Curtis, 1983). Dust and ammonia have been associated with respiratory disease in poultry (Hauser and Folsch, 1988). In cool climates, lowered temperatures can be used to reduce dust levels in the air. Lighting programs, such as intermittent light schedules, improve BW gain and at times feed efficiency (Buckland, 1975; Siopes et al., 1986). Apparently, limiting bird activity during the scotophase results in conservation of energy (Foshee et al., 1970; Ketelaars et al., 1986). Combining short-term temperature cycles with intermittent light may moderate air quality and improve performance. The use of cooler temperatures during the light period may increase relative humidity to reduce dust levels when bird activity is die highest. During the dark period, die temperature may be increased to allow better feed efficiency with less concern over dust levels during a time of reduced activity.
923
Downloaded from http://ps.oxfordjournals.org/ at University of North Dakota on May 16, 2015
ABSTRACT The performance of 1,312 male market turkeys (Large White, Nicholas strain) from 0 to 20 wk of age fed diets varying in feed form and energy level was measured under two stocking densities (21 or .46 m 2 per bird) and four lighting and temperature programs. The four diets were 1) corn and soybean meal with 1% supplemental fat, mash (CSM); 2) as 1, pelleted (CSP); 3) as Diet 1 but with 1, 2, 4, 6, and 8% supplemental fat during 0 to 4,4 to 8,8 to 12,12 to 16, and 16 to 20 wk of age, respectively (CSF); and 4) as Diet 1 but with barley included at 0,20,35,50, and 65% during the respective 4-wk age periods (CSB). The four light and temperature programs were 1) Environment A with intermittent light [4[2 h light (L):4 h dark (D)]] in combination with cycling temperature at 7 and 21 C during light and dark photoperiod, respectively; Environment B with intermittent light, 21 C; Environment C with continuous light (18L:6D) and cycling temperature of 7 to 21C; and Environment D with intermittent light, 7 C. Lighting and temperature programs started at 1 and 4 wk of age, respectively. Body weights at 20 wk of age decreased (P t-; cs
tt
2 2
cs —
0
S 0< PL, 0 3 CO 0 0 0 0 GO O O U U
•J EC
^•a H
K
£ • & H4 PH
U
O
U
U
U
Q
CS
« •§ A "§ O O O H ( S i n en «-j - ^ en en en en
"! •*. T t Tf
00
! en
Downloaded from http://ps.oxfordjournals.org/ at University of North Dakota on May 16, 2015
fl rt 0 \ 00 ri 3 00 os CS CS
rt ^t -q; en*
T—(
Tt I t
0
a xi vn r^ rt in
CSM = coirn and so soybean 1md barle;
rt .O »-< en i t p en en
I—1
t-%
where L =
rt ctf rt rt rt H i n m w «n i t cs. ^H T t »n en en en en en*
rt rt Os * t
fat; 3 nods
fl en cs -^
; with 1' cessive
e4 st O rt fl fl 0 rt rt , 0 0 rt i n --* I O H O S H e n ^ - ^ v o «* m 0 vq 0 0 ^ t en vo t-^ en en 00 i > 0 0 en - ^ T t T t en i t "+' - 0 5 OS >ft t n Os en fl d O i t
and so;
II
JS-V^&t.
931
TURKEY DIET AND ENVIRONMENT TABLE 5. Effect of environment on air levels of dust, ammonia, aspergillus, and relative humidity Environment "^ Age (wk)
A
B
8 12 16 20 8 12 16 20 6 11 14
3.10 2.76 2.97 3.50 14 21 14 18 1.2 2 0 64 (14.2)2 64 (14.2) 62 (16.1)
3.11 10.20 7.20 11.40 16 30 32 38 0 942 2
Ammonia, ppm
Aspergillus, cfu/nr
Relative humidity, %
8 to 12 12 to 16 16 to 20
D
C 5.66 4.78 4.55 4.66 4 32 8 14 0 264 0
53 (21.7) 58 (21.1) 52 (22.5)
61 (13.3) 59 (13.6) 56 (15.5)
2.24 1.70 2.86 2.88 2 4 10 32 0 46 0 60 ( 9.2) 76 ( 8.6) 65 (12.2)
^vironment descriptions: A = [4(2L:4D)], 7 to 21C; B = [4(2L:4D)], 21C; C = 18L:6D, 7 to 21C; D = [4(2L:4D)], 7 C, where L = hours of light and D = hours of dark. 2 Data were not statistically analyzed. parentheses, average temperature (C) at the time of sampling for relative humidity.
TABLE 6. Litter moisture as affected by environment, diet, and bird density with ANOVA summary Age, wk Variable
12
16
20
(%) Environment1 (lighting and temperature) A. 4(2L:4D):7 to 21 C B. 4(2L:4D):21 C C. 18L:6D:7 to 21 C D. 4(2L:4D):7 C Diet2 1. CSM 2. CSP 3. CSF 4. CSB Bird density, m 2 per bird Low (.46) High (.21)
34.0" 29.2C 34.9b 40.1"
35.7" 31.7b 35.3 b 41.0"
32.7" 27.8C 35.5 b 40.0 s
32.3" 37.7a 32.2b 36.0 s
35.5ab 38.7a 33.0 b 36^*
33.2 35.5 32.7 34.5
30.2b 39.0 s
31.0 b 40.8 a
31.4 b 36.5 s
ANOVA summary Source of variation Environment (env) Diet Bird density (den) Env x diet Env x den Diet x den Env x diet x den
.0001 .002 .0001 .097 .089 .53 .031
Probability .0009 .096 .0001 22 51 .77 .88
.0001 .20 .0001 .51 .17 .63 .27
"""Means within columns and variables with no common superscripts are significantly different *L = hours of light; D = hours of dark. 2 Diets: 1) CSM=com and soybean mash with 1 % added fat; 2) CSP = com and soybean pellets with 1% added fat; 3) CSF = com and soybean mash with 1 to 8% added fat; 4) CSB = corn, soybean and barley mash with 0,20,35,50, and 65% barley in diet during successive 4-wk periods.
Downloaded from http://ps.oxfordjournals.org/ at University of North Dakota on May 16, 2015
Measurement Dust, mg/nr
932
NOLL ET AL. TABLE 7. Effect of environment, diet, and bird density on airsacculitis and isolation of aspergUlus from lungs sampled at time of processing in male turkeys (Nicholas strain) at 20 wk of age with ANOVA summary
Variable
Environment (lighting and temperature)2 A. 4(2L:4D):7 to 21 C B. 4(2L:4D):21 C C. 18L:6D:7 to 21 C D. 4(2L:4D):7 C
Incidence of airsacculitis
Aspergillus isolation1
(%)
(spores per g lung)
9.4b 45.3 a 15.8b 3.1 b
697b 3,387a 335 b 141b
15.61 29.7 a 23.4'ab 4.7°
1,140
11.7b 25.0*
822 1,457
Diet 3
CSM CSP CSF CSB
Bird density, m 2 per bird Low (.46) High (.21) ANOVA summary Source of variation Environment (env) Diet Bird density (den) Env x diet Env x den Diet x den Env x diet x den
.0001 .003 .006 .41 .24 .22 .26
.041 .32 .58
a c
~ Means within columns and variable with no common superscripts are significantly different (P. dissertation, University of Minnesota, St. Paul, MN. Nagaraja, K. V., D. A. Emery, K. A. Jordan, J. A. Newman, and B. S. Pomeroy, 1984. Scanning electron microscopic studies of adverse effects of ammonia on tracheal tissues of turkeys. Am. J. Vet Res. 44:1530-1536. National Research Council, 1981. Effect of Environment on Nutrient Requirements of Domestic Animals. National Academy of Sciences, Washington, DC. National Research Council, 1984. Nutrient Requirements of Poultry. 8th ed. National Academy of Sciences, Washington, DC. Newman, R. K., and C. W. Newman, 1988. Nutritive value of a new hull-less barley cultivar in broiler chick diets. Poultry Sci. 67:1573-1579. Owen, J. A., P. W. Waldroup, C. J. Mabray, and P. J. Slagter, 1981. Response of growing turkeys to dietary energy levels. Poultry Sci. 60:418-424. Pepper, W. F., S. J. Slinger, and J. D. Summers, 1960. Studies with chickens and turkeys on the relationship between fat, unidentified factors, and pelleting. Poultry Sci. 39:66-74. Sell, J. L., and W. J. Owings, 1981. Supplemental fat and metabolizable energy-to-nutrient ratios for growing turkeys. Poultry Sci. 60:2293-2305. Siopes, T. D., C. R. Parkhurst and G. R. Baughman, 1986. Intermittent light and growth performance of male turkeys from 2 to 22 weeks of age. Poultry Sci. 65: 2221-2225. Steele, R.GX>., and J. J. Torrie, 1980. Principles and Procedures of Statistics. 2nd ed. McGraw-Hill Book Company, New York, NY. Waibel, P. E., M E. El Halawani, and B. R. Behrends, 1976. Growth and efficiency of Large White turkeys in relation to dietary protein and environmental temperatures. Pages 119-125 in: Proceedings of the 37th Minnesota Nutrition Conference, University of Minnesota, St. Paul, MN. Waibel, P. E., M. E. El Halawani, and S. L. Noll, 1979. Environment-nutrition interrelationship effects on turkey production. Pages 111-120 in: Proceedings of the Minnesota Nutrition Conference, University of Minnesota, St. Paul, MN.
Downloaded from http://ps.oxfordjournals.org/ at University of North Dakota on May 16, 2015
Charles, D. R., 1989. Environmental responses of growing turkeys. Pages 201-214 in: Recent Advances in Turkey Science. Poultry Science Symposium No. 21. C. Nixey and T. C. Grey, ed. Butterworths, London, England. Curtis, S. E., 1983. Environmental Management in Animal Agriculture. Iowa State University Press, Ames, IA. Dale, N. M„ and H. L. Fuller, 1980. Effect of diet composition on feed intake and growth of chicks under heat stress, n. Constant versus cycling temperatures. Poultry Sci. 59:1434-1441. de Albuquerque, K., A. T. Leighton, Jr., J. P. Mason, Jr., and L. M. Potter, 1978. The effects of environmental temperature, sex, and dietary energy levels on growth performance of Large White turkeys. Poultry Sci. 57:353-362. Denbow, D. M., A. T. Leighton, Jr., and R. M Hulet, 1984. Behavior and growth parameters of Large White turkeys as affected by floor space and beak trimming. 1. Males. Poultry Sci. 63:31-37. Dymsza, H., R. V. Boucher, and M. G. McCartney, 1955. The influence of fiber content and physical form of the diet on the energy requirement of turkeys. Poultry Sci. 34:435-439. Foshee, D. P., D. M. Certa, G. R. McDaniel, and C. A. Rollo, 1970. Diurnal activity patterns of broilers in a controlled environment. Poultry Sci. 49:1514-1518. Hauser, R. H., and D. W. Folsch, 1988. Methods for measuring atmospheric dust, micro-organisms, and ammonia in poultry houses: Review and approved practices. J. Vet Med. B35:579-593. Hurwitz, S., and I. Bengal, 1982. Energy use and performance of young turkeys kept under various constant and cycling environmental temperatures. Poultry Sci. 61:1082-1086. Hurwitz, S., M. Weiselberg, U. Eisner, I. Bartov, G. Riesenfeld, M. Sharvit, and S. Bornstein, 1980. The energy requirements and performance of growing chickens and turkeys as affected by environmental temperature. Poultry Sci. 59:2290-2299. Jensen, L. S., and L. Falen, 1973. Effect of pelleting on the extra caloric effect of dietary fat for developing turkeys. Poultry Sci. 52:2342-2344. Jensen, L. S., L. H. Merrill, C. V. Reddy, and J. McGinnis, 1962. Observations on eating patterns and rate of food passage of birds fed pelleted and unpelleted diets. Poultry Sci. 41:1415-1419. Johnson, R. L., 1988. Space allowances: What's adequate or tolerable. Gobbles 44(1): 14-16. Jordan, K. A., L. G. Fanella, S. Sokhansanj, and T. L. Weisbecker, 1978. Stocking area of turkeys affect on mortality and profit. Pages 78-81 in: Minnesota Turkey Research Miscellaneous Report 165, Univer-
1991 Poultry Science 70:923-934 INTRODUCTION
Performance of turkeys is affected by both nutrition and ambient environment. Temperature impacts performance primarily through its effect on feed consumption and subsequent BW gain, which decreases as temperature increases (National Research Council, NRC, 1981). However, minimum feed:gain ratios are reached at warm environmental temperatures. Therefore, the selection of rearing temperature is often influenced by relative feed to fuel cost (Waibel et al, 1976; Charles, 1989). In confinement buildings, ambient temperature alters the water-holding capacity of the air, which in turn affects litter moisture and
^Wished as Paper Number 18392, Scientific Journal Series, Minnesota Agricultural Experiment Station. T"o whom correspondence should be addressed. department of Animal Science. 4 Department of Veterinary Biology. Department of Agricultural Engineering.
dust and ammonia concentrations (Curtis, 1983). Dust and ammonia have been associated with respiratory disease in poultry (Hauser and Folsch, 1988). In cool climates, lowered temperatures can be used to reduce dust levels in the air. Lighting programs, such as intermittent light schedules, improve BW gain and at times feed efficiency (Buckland, 1975; Siopes et al., 1986). Apparently, limiting bird activity during the scotophase results in conservation of energy (Foshee et al., 1970; Ketelaars et al., 1986). Combining short-term temperature cycles with intermittent light may moderate air quality and improve performance. The use of cooler temperatures during the light period may increase relative humidity to reduce dust levels when bird activity is die highest. During the dark period, die temperature may be increased to allow better feed efficiency with less concern over dust levels during a time of reduced activity.
923
Downloaded from http://ps.oxfordjournals.org/ at University of North Dakota on May 16, 2015
ABSTRACT The performance of 1,312 male market turkeys (Large White, Nicholas strain) from 0 to 20 wk of age fed diets varying in feed form and energy level was measured under two stocking densities (21 or .46 m 2 per bird) and four lighting and temperature programs. The four diets were 1) corn and soybean meal with 1% supplemental fat, mash (CSM); 2) as 1, pelleted (CSP); 3) as Diet 1 but with 1, 2, 4, 6, and 8% supplemental fat during 0 to 4,4 to 8,8 to 12,12 to 16, and 16 to 20 wk of age, respectively (CSF); and 4) as Diet 1 but with barley included at 0,20,35,50, and 65% during the respective 4-wk age periods (CSB). The four light and temperature programs were 1) Environment A with intermittent light [4[2 h light (L):4 h dark (D)]] in combination with cycling temperature at 7 and 21 C during light and dark photoperiod, respectively; Environment B with intermittent light, 21 C; Environment C with continuous light (18L:6D) and cycling temperature of 7 to 21C; and Environment D with intermittent light, 7 C. Lighting and temperature programs started at 1 and 4 wk of age, respectively. Body weights at 20 wk of age decreased (P t-; cs
tt
2 2
cs —
0
S 0< PL, 0 3 CO 0 0 0 0 GO O O U U
•J EC
^•a H
K
£ • & H4 PH
U
O
U
U
U
Q
CS
« •§ A "§ O O O H ( S i n en «-j - ^ en en en en
"! •*. T t Tf
00
! en
Downloaded from http://ps.oxfordjournals.org/ at University of North Dakota on May 16, 2015
fl rt 0 \ 00 ri 3 00 os CS CS
rt ^t -q; en*
T—(
Tt I t
0
a xi vn r^ rt in
CSM = coirn and so soybean 1md barle;
rt .O »-< en i t p en en
I—1
t-%
where L =
rt ctf rt rt rt H i n m w «n i t cs. ^H T t »n en en en en en*
rt rt Os * t
fat; 3 nods
fl en cs -^
; with 1' cessive
e4 st O rt fl fl 0 rt rt , 0 0 rt i n --* I O H O S H e n ^ - ^ v o «* m 0 vq 0 0 ^ t en vo t-^ en en 00 i > 0 0 en - ^ T t T t en i t "+' - 0 5 OS >ft t n Os en fl d O i t
and so;
II
JS-V^&t.
931
TURKEY DIET AND ENVIRONMENT TABLE 5. Effect of environment on air levels of dust, ammonia, aspergillus, and relative humidity Environment "^ Age (wk)
A
B
8 12 16 20 8 12 16 20 6 11 14
3.10 2.76 2.97 3.50 14 21 14 18 1.2 2 0 64 (14.2)2 64 (14.2) 62 (16.1)
3.11 10.20 7.20 11.40 16 30 32 38 0 942 2
Ammonia, ppm
Aspergillus, cfu/nr
Relative humidity, %
8 to 12 12 to 16 16 to 20
D
C 5.66 4.78 4.55 4.66 4 32 8 14 0 264 0
53 (21.7) 58 (21.1) 52 (22.5)
61 (13.3) 59 (13.6) 56 (15.5)
2.24 1.70 2.86 2.88 2 4 10 32 0 46 0 60 ( 9.2) 76 ( 8.6) 65 (12.2)
^vironment descriptions: A = [4(2L:4D)], 7 to 21C; B = [4(2L:4D)], 21C; C = 18L:6D, 7 to 21C; D = [4(2L:4D)], 7 C, where L = hours of light and D = hours of dark. 2 Data were not statistically analyzed. parentheses, average temperature (C) at the time of sampling for relative humidity.
TABLE 6. Litter moisture as affected by environment, diet, and bird density with ANOVA summary Age, wk Variable
12
16
20
(%) Environment1 (lighting and temperature) A. 4(2L:4D):7 to 21 C B. 4(2L:4D):21 C C. 18L:6D:7 to 21 C D. 4(2L:4D):7 C Diet2 1. CSM 2. CSP 3. CSF 4. CSB Bird density, m 2 per bird Low (.46) High (.21)
34.0" 29.2C 34.9b 40.1"
35.7" 31.7b 35.3 b 41.0"
32.7" 27.8C 35.5 b 40.0 s
32.3" 37.7a 32.2b 36.0 s
35.5ab 38.7a 33.0 b 36^*
33.2 35.5 32.7 34.5
30.2b 39.0 s
31.0 b 40.8 a
31.4 b 36.5 s
ANOVA summary Source of variation Environment (env) Diet Bird density (den) Env x diet Env x den Diet x den Env x diet x den
.0001 .002 .0001 .097 .089 .53 .031
Probability .0009 .096 .0001 22 51 .77 .88
.0001 .20 .0001 .51 .17 .63 .27
"""Means within columns and variables with no common superscripts are significantly different *L = hours of light; D = hours of dark. 2 Diets: 1) CSM=com and soybean mash with 1 % added fat; 2) CSP = com and soybean pellets with 1% added fat; 3) CSF = com and soybean mash with 1 to 8% added fat; 4) CSB = corn, soybean and barley mash with 0,20,35,50, and 65% barley in diet during successive 4-wk periods.
Downloaded from http://ps.oxfordjournals.org/ at University of North Dakota on May 16, 2015
Measurement Dust, mg/nr
932
NOLL ET AL. TABLE 7. Effect of environment, diet, and bird density on airsacculitis and isolation of aspergUlus from lungs sampled at time of processing in male turkeys (Nicholas strain) at 20 wk of age with ANOVA summary
Variable
Environment (lighting and temperature)2 A. 4(2L:4D):7 to 21 C B. 4(2L:4D):21 C C. 18L:6D:7 to 21 C D. 4(2L:4D):7 C
Incidence of airsacculitis
Aspergillus isolation1
(%)
(spores per g lung)
9.4b 45.3 a 15.8b 3.1 b
697b 3,387a 335 b 141b
15.61 29.7 a 23.4'ab 4.7°
1,140
11.7b 25.0*
822 1,457
Diet 3
CSM CSP CSF CSB
Bird density, m 2 per bird Low (.46) High (.21) ANOVA summary Source of variation Environment (env) Diet Bird density (den) Env x diet Env x den Diet x den Env x diet x den
.0001 .003 .006 .41 .24 .22 .26
.041 .32 .58
a c
~ Means within columns and variable with no common superscripts are significantly different (P. dissertation, University of Minnesota, St. Paul, MN. Nagaraja, K. V., D. A. Emery, K. A. Jordan, J. A. Newman, and B. S. Pomeroy, 1984. Scanning electron microscopic studies of adverse effects of ammonia on tracheal tissues of turkeys. Am. J. Vet Res. 44:1530-1536. National Research Council, 1981. Effect of Environment on Nutrient Requirements of Domestic Animals. National Academy of Sciences, Washington, DC. National Research Council, 1984. Nutrient Requirements of Poultry. 8th ed. National Academy of Sciences, Washington, DC. Newman, R. K., and C. W. Newman, 1988. Nutritive value of a new hull-less barley cultivar in broiler chick diets. Poultry Sci. 67:1573-1579. Owen, J. A., P. W. Waldroup, C. J. Mabray, and P. J. Slagter, 1981. Response of growing turkeys to dietary energy levels. Poultry Sci. 60:418-424. Pepper, W. F., S. J. Slinger, and J. D. Summers, 1960. Studies with chickens and turkeys on the relationship between fat, unidentified factors, and pelleting. Poultry Sci. 39:66-74. Sell, J. L., and W. J. Owings, 1981. Supplemental fat and metabolizable energy-to-nutrient ratios for growing turkeys. Poultry Sci. 60:2293-2305. Siopes, T. D., C. R. Parkhurst and G. R. Baughman, 1986. Intermittent light and growth performance of male turkeys from 2 to 22 weeks of age. Poultry Sci. 65: 2221-2225. Steele, R.GX>., and J. J. Torrie, 1980. Principles and Procedures of Statistics. 2nd ed. McGraw-Hill Book Company, New York, NY. Waibel, P. E., M E. El Halawani, and B. R. Behrends, 1976. Growth and efficiency of Large White turkeys in relation to dietary protein and environmental temperatures. Pages 119-125 in: Proceedings of the 37th Minnesota Nutrition Conference, University of Minnesota, St. Paul, MN. Waibel, P. E., M. E. El Halawani, and S. L. Noll, 1979. Environment-nutrition interrelationship effects on turkey production. Pages 111-120 in: Proceedings of the Minnesota Nutrition Conference, University of Minnesota, St. Paul, MN.
Downloaded from http://ps.oxfordjournals.org/ at University of North Dakota on May 16, 2015
Charles, D. R., 1989. Environmental responses of growing turkeys. Pages 201-214 in: Recent Advances in Turkey Science. Poultry Science Symposium No. 21. C. Nixey and T. C. Grey, ed. Butterworths, London, England. Curtis, S. E., 1983. Environmental Management in Animal Agriculture. Iowa State University Press, Ames, IA. Dale, N. M„ and H. L. Fuller, 1980. Effect of diet composition on feed intake and growth of chicks under heat stress, n. Constant versus cycling temperatures. Poultry Sci. 59:1434-1441. de Albuquerque, K., A. T. Leighton, Jr., J. P. Mason, Jr., and L. M. Potter, 1978. The effects of environmental temperature, sex, and dietary energy levels on growth performance of Large White turkeys. Poultry Sci. 57:353-362. Denbow, D. M., A. T. Leighton, Jr., and R. M Hulet, 1984. Behavior and growth parameters of Large White turkeys as affected by floor space and beak trimming. 1. Males. Poultry Sci. 63:31-37. Dymsza, H., R. V. Boucher, and M. G. McCartney, 1955. The influence of fiber content and physical form of the diet on the energy requirement of turkeys. Poultry Sci. 34:435-439. Foshee, D. P., D. M. Certa, G. R. McDaniel, and C. A. Rollo, 1970. Diurnal activity patterns of broilers in a controlled environment. Poultry Sci. 49:1514-1518. Hauser, R. H., and D. W. Folsch, 1988. Methods for measuring atmospheric dust, micro-organisms, and ammonia in poultry houses: Review and approved practices. J. Vet Med. B35:579-593. Hurwitz, S., and I. Bengal, 1982. Energy use and performance of young turkeys kept under various constant and cycling environmental temperatures. Poultry Sci. 61:1082-1086. Hurwitz, S., M. Weiselberg, U. Eisner, I. Bartov, G. Riesenfeld, M. Sharvit, and S. Bornstein, 1980. The energy requirements and performance of growing chickens and turkeys as affected by environmental temperature. Poultry Sci. 59:2290-2299. Jensen, L. S., and L. Falen, 1973. Effect of pelleting on the extra caloric effect of dietary fat for developing turkeys. Poultry Sci. 52:2342-2344. Jensen, L. S., L. H. Merrill, C. V. Reddy, and J. McGinnis, 1962. Observations on eating patterns and rate of food passage of birds fed pelleted and unpelleted diets. Poultry Sci. 41:1415-1419. Johnson, R. L., 1988. Space allowances: What's adequate or tolerable. Gobbles 44(1): 14-16. Jordan, K. A., L. G. Fanella, S. Sokhansanj, and T. L. Weisbecker, 1978. Stocking area of turkeys affect on mortality and profit. Pages 78-81 in: Minnesota Turkey Research Miscellaneous Report 165, Univer-
