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Changes in Seasonal Egg Production of Turkeys Induced Through Controlled Light Exposure and Force Moulting1
Changes in Seasonal Egg Production of Turkeys Induced Through Controlled Light Exposure and Force Moulting 1 J. A. HARPER AND J. E. PARKER
Oregon Agricultural Experiment Station, Corvallis (Received for publication March 18, 1957)
T
LITERATURE REVIEW
The egg production patterns of a seasonal and year to year nature for turkeys have been reported by Asmundson and Lloyd (193S) and Marsden (1936). Asmundson (1941) found that, with Bronze turkeys selected for early maturity, it is possible to obtain more eggs during the breeding season and throughout the year. Egg production of Beltsville Small White turkeys was reported by 1
Technical Paper No. 1034, Oregon Agricultural Experiment Station. Supported in part by a grant from the National Turkey Federation.
Knox and Marsden (1954) to be improved by use of selection based on trapnest records and an increase was obtained of 79.6 to 146.2 eggs per hen from January 1 to October 1, during the period from 1944 to 1951. As a general observation turkey breeding flocks fail to produce eggs at a satisfactory rate during the summer months. This appears to be especially true for young hens hatched in the late fall and winter months that normally would reach sexual maturity in seven or eight months (Harper, 1955). While the cause for a low rate of production is not known there is evidence available, from other species of birds indicating that light plays an important role. The effect of light in stimulus and control of the reproductive activity of plants and animals has been the subject of numerous investigations. Much of the early work with the avian species has been reviewed by Bissonnette (1936). Benoit (1938) in experiments with ducks observed the stimulating effect of light on the optic nerve and linkage with activity of the hypophysis. The effectiveness of artificial light to stimulate turkey hens to lay earlier during periods of short day length was demonstrated by the Nebraska Agricultural Experiment Station (1930) and Albright and Thompson (1933). The influence of age of turkeys and effect of light on production has been reported by Margolf, Harper and Callenbach (1947). More recently Asmundson and Moses (1950) investigated the influence of day length on egg produc-
967
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HE turkey industry has operated largely on a seasonal basis and little attention has been given to out-of-season production until the recent interest in marketing of turkey broilers. While the seasonal nature of turkey production may be attributed partly to holiday demands, weather limitations in some areas of production and the normal breeding cycle of turkeys, there is little reason to believe the pattern of production cannot be altered. There are at least two possible approaches to the problem of obtaining eggs from turkey hens for hatching purposes throughout the year. One of these is by means of genetic selection to gain persistency of egg production as has been followed by chicken breeders. The second is through possible changes in environment of young hens hatched out-of-season or yearling hens that have completed several months of lay. The second approach has been used in experiments reported herein.
968
J. A. HARPER AND J. E. PARKER
8 hour day length from 14 or 16 to the 28 or 30th week of age, then exposed to a 14 hour light day. PROCEDURE
Experiments with young hens {1953).— A group of 50 range-reared Beltsville Small White hens hatched February 18, 1953 were assorted at random and placed in 5 pens when 23 weeks of age on August 1. The treatments were as follows: 10 hens kept in an outside yard with a shelter; the 40 remaining were kept in pens of 10 each in a wire sided pole house and these four pens were restricted to 9 hours of light each day for 0, 7, 14 and 21 days. The hens on restricted light were driven into dark pens at 5:00 p.m. each day and released to pens with natural light at 8:00 a.m. the following morning. The hens in the outside yard and two pens in the pole house receiving 0 and 7 days restricted light were provided with a total of 17 hours of light per day on August 8. On August 15 and 22 the 14 and 21 day restricted light pens, respectively, were also provided with 17 hours of total light daily. (1954)—A group of 90 Beltsville Small White hens hatched in November 1953 were managed together in a brooder house to 15 weeks of age and range reared to June 1, 1954, when 27 weeks of age. Three pens of 30 hens each were assorted at random and moved to pens of the pole house. The control pens were maintained under natural daily light for four weeks. The other two pens were restricted to a 9 hour daily light period from June 1 to either June 15 or 29. The three pens were then provided with a daily light period totaling 17 hours after the treatments of 0, 14 and 28 days of restricted light. (1956)—A group of 120 Beltsville Small White hens hatched on December 13 and 27, 1955, were brooded to March 1
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tion and concluded that a total daily light period of 13-15 hours was about optimum. The experiments with turkeys cited above were conducted in periods of short natural day length when the stimulation from light would be most effective. In other avian species it has been postulated that following a period of gonadal stimulation induced by long day lengths there is a refractory period during which further increases in daily light does not evoke further gonadal development. Short daily light periods, are required to end the refractory period according to Damste (1947) and Wolfson (1952). Kirkpatrick and Leopold (1952) in experiments with quail concluded that night or dark periods exert a specific influence on photoperiodic response. Farner, Mewalt and Irving (1953) working with sparrows using light exposure at 10, 12.2, 18 and three other 10 hour groups with light interruption of dark periods, found equal stimulation of gonads from 18 hours of continuous light and 10 hours interrupted by nine periods of 1.11 hours of darkness. Piatt (1955) reported that White Leghorn pullets hatched in January, maintained on a regular day length or restricted to an 8 hour day length at three months of age, followed by a 14 hour day length on August 28, laid at a higher rate when coming into production if lighting had been restricted. Hutchinson (1956) reared Brown Leghorn pullets from 8 weeks of age through the second month of lay on either a daily light exposure of 12 or 2 3 | hours per day. Following the two months production period light was gradually reduced for the latter group to 16 hours per day. It was observed that egg production declined and a molt occurred. With turkeys hatched at different seasons of the year Marr el al. (1956) observed better subsequent egg production from hens hatched in January subjected to an
SEASONAL EGG PRODUCTION OF TURKEYS
969
TABLE 1.—Effect of reducing daily light for varying intervals on subsequent egg production of Beltsville Small White turkeys (1953—10 young hens per pen) Egg production—Percent hen days uigiil. u c a i u i c u i
Range Confined Confined Confined Confined
Natural Natural 9 hrs. 9 hrs. 9 hrs.
8/1 8/1 8/1 8/1 8/1
17 hrs. 17 hrs. 17 hrs. 17 hrs. 17 hrs.
8/8 8/8 8/8 8/15 8/20
Sept.
Oct.
Nov. 20
Mean 1
31.0 14.2 15.2 38.1 40,6
24.5 37.1 42.6 48.1 51.6
17.5 26.0 29.5 34.0 53.0
25.2 26.0 29.4 40.1 48.4
in confinement and range reared to June 1 when 22 or 24 weeks of age. The hens were then allotted at random into six pens of 20 hens each, with three pens maintained thereafter in the pole house and three pens in outside yards. Sub-groups under each management conditions were maintained under natural light, restricted to a 9 hour day length for 4 weeks or injected intramuscularly with 40 or 80 milligrams of progesterone. The three pens in the pole house were exposed to a 17 hour total daily light period starting June 29. The hens in outside yards were maintained under prevailing natural light to the end of the experimental period on November 14, 1956. Experiments with Yearling Hens (1955). —Two groups of 40 Beltsville Small White and 40 crossbred white (F2 BBB XBSW) turkey hens completing six months of lay to June 22 were divided into duplicate pens of 10 hens each according to origin. The duplicate pens were either restricted to a 9 hour day length for four weeks or force molted by removal of water for 24 hours and feed for 36 hours. The hens were maintained in the pole house and subjected to a 17 hour day length on July 21. (1956)—A group of 39 crossbred white (F 3 BBB XBSW) hens completing six months of lay to June 1 were divided
equally in 3 pens. The hens were managed in the pole house. One pen was maintained to August 1 on natural light. A second pen was force molted by intramuscular injection of 40 mg. of progesterone per bird on June 1. The hens in the third pen were restricted to a 9 hour day length from June 1 to 28. All hens were provided with 17 hours of light per day beginning August 1. RESULTS AND DISCUSSION
The results of the experiment with young Beltsville Small White hens in 1953 are shown in Table 1. Egg production of the hens on range or in confinement and provided 17 hours of light per day averaged 25.2 and 26.0 percent from September 1 to November 20. The pens restricted to a 9 hour day length for 1, 2 and 3 weeks and subsequently subjected to 17 hours of light stimulation averaged 29.4, 40.1 and 48.4 percent, respectively. Both trapnest records and examination of oviducts of hens in non-restricted light pens showed that only five birds in each were in production. It would appear that turkey hens reared during periods of long day length, as were the control groups, are refractory to additional light as reported for other avian species by Damste (1947) and Wolfson (1952) and become responsive when subjected to a two or
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!L.S.D. (.05) = 21.7. L.S.D. (.01) = 29.1.
970
J. A. HARPER AND J. E. PARKER TABLE 2.—Effect of reducing daily light for varying intervals on subsequent egg production of Beltsville Small White turkeys (1954—30 young hens per pen) Egg production—Percent hen days
Natural 6/1 9 hrs. 6/15 9 hrs. 6/1 1
17 hrs. 6/29 17 hrs. 6/29 17 hrs. 6/29
June 14
July
Aug.
Sept.
Oct. 28
Mean 1
35.2 12.5 11.9
46.2 26.8 28.8
38.7 34.5 59.7
42.9 46.7 54.7
38.2 42.1 53.7
36.8 31.0 40.3
L.S.D. (.05)= 8.33. L.S.D. (.01) = 11.04.
on egg production recorded in Table 2 show the suppression of laying during June and July for the restricted light hens as compared to the control pens. Following stimulation by light the hens that had been on restricted light laid at a higher rate than the hens maintained on natural light. In 1956 the 120 young Beltsville Small White hens were subjected to treatments as outlined previously on June 1 when they were 22 or 24 weeks of age. The results of this experiment are shown in Table 3. Use of progesterone to force molt the hens prior to laying was tried since it had been noted that restricted lighting in previous years induced a partial molt. Further it was realized that if molt was associated with subsequent egg production, and the same effect could be obtained with progesterone as with restricted light-
TABLE 3.—Effect of reducing light and progesterone injection on subsequent egg production on Beltsville Small White turkeys (1956—20 young hens per pen) Egg production—Percent hen days July
Aug.
Sept.
Oct.
Nov.
Means 1
Confined Confined Confined
Natural 6/1 Prog. 80 mg. 6/1 6 hrs. 6/1
17 hrs. 17 hrs. 17 hrs.
6/29 6/29 6/29
18.2 0.0 21.3
19.5 6.4 66.5
23.8 19.6 62.0
19.5 29.5 55.0
25.9 42.1 44.5
20.7 15.9 50.5
Range Range Range
Natural 6/1 Prog. 40 mg. 6/1 9 hrs. 6/1
Natural 6/1 Natural 6/1 Natural 6/29
11.6 1.8 19.0
20.6 4.8 63.4
13.7 9.3 45.6
16.1 10.0 17.1
11.8 12.3 3.6
15.2 6.9 33.5
1
L.S.D. (.05) = 10.7. L.S.D. (.01) = 14.2.
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three week period on a nine hour day length prior to laying. In 1954 the three pens of young Beltsville Small White hens were 27 weeks of age at the time when subjected to treatments of 0,14 or 28 days of restricted light on June 1. The results of this experiment are shown in Table 2. Egg production on a hen-day basis averaged 36.8, 31.0 and 40.3 percent, respectively. The rate of lay was in this year higher for the non-restricted light hens than in 1953 and the differences between treatments not very large. The highest rate of lay, however, was still in favor of the turkey hens subjected to 4 weeks of restricted light. Some hens were in production at the time restricted light treatments were imposed and subsequently ceased laying. These hens required a longer period to return to lay. The effects of the various treatments
SEASONAL EGG PRODUCTION OF TURKEYS
TABLE 4.—Effect
Experiments with yearling hens having completed 6 months of lay were directed toward determining if an efficient rate of production could be obtained following force molting or restriction to a short day length. In 1954, four weeks following force molting by starvation or subjection to a 9 hour day length, the hens were exposed to a total of 17 hours of light daily. As shown in Table 4 during the following months from August to November 20, the hens laid at a rate of from 6.7 to 20.3 percent. In 1956, the yearling hens were maintained after June 1 on natural light, subjected to 9 hours of light per day for four weeks or given 40 mg. of progesterone. In contrast to the previous year a period of eight and one-half weeks "rest" was provided instead of four weeks. The results are shown in Table 5. The percentage rate of lay was 2.2, 13.1 and 1.5 for the three pens, respectively. While being higher in the restricted light pen than the other two groups, the rate of lay was very low. Shell quality of eggs laid by all yearling hens was poor. It is clear that under the various regimes used in both years for yearling hens the rate of lay was too low to maintain hens for a second period of hatching
of a reduction in daily light period or force molting by starvation on subsequent egg production of yearling turkeys (1955—10 hens per pen) Egg production —Number per pen
Variety
Light tr eatment
%
Aug.
Sept.
Oct.
Nov. 28
Total
Hen day basis
B.S.W. B.S.W. B.S.W. B.S.W.
9 hrs. 9 hrs. Starvation* Starvation*
6/22 6/22 6/22 6/22
17 17 17 17
hrs. hrs. hrs. hrs.
7/20 7/20 7/20 7/20
18 21 0 9
48 30 0 38
55 51 38 56
123 118 135 63
244 210 173 166
20.3 17.5 14.4 13.8
X-Bred X-Bred X-Bred X-Bred
9 hrs. 9 hrs. Starvation Starvation
6/22 6/22 6/22 6/22
17 17 17 17
hrs. hrs. hrs. hrs.
7/20 7/20 7/20 7/20
3 1 1 0
10 18 11 12
14 31 23 67
65 31 62 128
92 81 97 207
7.7 6.7 8.1 17.2
* Water removed 24 hours and feed 36 hours.
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ing, there would be a possibility of wider application under commercial conditions of breeder hen management. The rate of lay for hens maintained in the pole house and subjected to a 17 hour day length following 0 to 4 weeks on a 9 hour daily light period averaged 20.7 and 50.5 percent, respectively. The hens treated with 80 mg. of progesterone underwent a heavy molt and until October remained below the control group in production. The three pens of hens maintained in outside yards with natural light after restricted light treatments followed a pattern of production in July and August similar to those on the 17-hour day length. In September and later months the effect of decreasing natural light resulted in lower egg production in all groups as compared with that of similar pens in the pole house. The pens treated with 40 mg. of progesterone molted as completely as the hens receiving 80 mg. of the hormone. At these levels progesterone caused a delay in production and not an earlier and greater response as has been reported by Nalbandov (1956) to occur with chickens injected with a 25 mg. level of progesterone prior to production.
971
972
J. A. HARPER AND J. E. PARKER TABLE 5.—Effect
of a reduction in daily light period, force molting or progesterone on subsequent egg production of yearling turkeys (1956—13 hens per pen) Egg production—Number per pen
Light treatment
Natural 6/1 9 hrs. 6/1 to 6/28 40 mg. Prog. 6/1
17 hrs. 8/1 17 hrs. 8/1 17 hrs. 8/1
%
July
Aug.
Sept.
Oct.
Nov.
Total
Hen day basis
36 46 4
0 94 0
0 38 0
0 42 17
0 16 2
36 236 23
2.2 13.1 1.5
SUMMARY Young Beltsville Small White turkey hens hatched in the winter months were found to lay at a low rate and showed evidence of being refractory to stimulation by two additional hours of light beyond the natural light of summer months. Young hens restricted to 9 hours of light per day when 22 or 24 weeks of age for a 3 or 4 week period produced eggs at a level of approximately 50 percent when exposed to the natural daily light length of summer months or by use of artificial lighting to provide 17 hours of total daily light. Egg production of these hens declined in September and later months unless the natural light hours were extended by artificial light. Progesterone at levels of 40 and 80 milligrams per young hen caused a heavy molt and egg production was depressed as compared to restricted or non-restricted light pens. Yearling hens force molted by starvation, progesterone or restriction to a 9 hour daily light length for 4 weeks, fol-
lowed by exposure to a 17-hour day length immediately or four and one-half weeks later, did not produce eggs at a satisfactory rate. REFERENCES Albright, W. P., and R. B. Thompson, 1933. Securing early turkeys by stimulated egg production. Poultry Sci. 12:124-128. Anonymous, 1930. Turkey production. Nebraska Agri. Exper. Sta. Ann. Report p. 39. Asmundson, V. S., 1941. Differences in sexual maturity and egg production in turkeys. Poultry Sci. 20: 51-56. Asmundson, V. S., and B. D. Moses, 1950. Influence of length of day on reproduction in turkey hens. Poultry Sci. 29: 34-41. Asmundson, V. S., and W. E. Lloyd, 1935. The effect of age on reproduction of the turkey hen. Poultry Sci. 14: 259-265. Benoit, J., 1938. Role des ycux et de la voie nerveuse oculo-hypophysaire dans le gonadostimulation par la lumiere artificielle chex le canard domestique. Compt. Rend. Soc. Biol. 129: 231-234. Bissonette, T. H., 1936. Sexual photoperiodicity. Quarterly Review of Biol. 371-386. Damste, P. H., 1947. Experimental modification of the sexual cycle of the green finch. J. Exp. Biol. 24: 20-35. Farner, D. S., L. R. Mewalt and S. D. Irving, 1953. The role of darkness and light in activation of avian gonads. Science, 118: 351-352. Harper, J. A., 1955. You can get hatching eggs the year 'round. Turkey World, 30: 17. Hutchinson, J. C. D., 1956. Control of seasonal variation in the egg production of hens. Nature, 177:795-796. Kirkpatrick, C. M., and A. C. Leopold, 1952. The role of darkness in sexual activity of quail. Science, 116: 280-281. Knox, C. W., and S. J. Marsden, 1954. Breeding for increased egg production in Beltsville Small
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egg production. Whether or not providing the hens with a longer rest period following a period of production would result in better egg production is open to question. The economy in maintaining the yearling hens as balanced against replacement with young hens having a potential of a higher rate of production would be an important consideration.
SEASONAL E G G PRODUCTION OF T U R K E Y S
White turkeys. Poultry Sci. 33:443^447. Margolf, P. H., J. A. Harper and E. W. Callenbach, 1947. Response of turkeys to artificial insemination. Pennsylvania Agri. Exper. Sta. Bui. 486. Marr, J. E., F. W. Garland, Jr., J. L. Milligan and H. L. Wilcke, 1956. Effect of controlled light during the growing period upon subsequent performance of breeder turkeys. Poultry Sci. 35:1156. Marsden, S. J., 1936. A study of egg production in
973
bronze turkeys. Poultry Sci. 15: 439-445. Nalbandov, A. V., 1950. Effect of progesterone in egg production. Poultry Sci. 35:1162. Piatt, C. S., 1955. A study of the effect of restricted lighting on January hatched pullets. Poultry Sci. 34: 1045-1047. Wolfson, A., 1952. The occurrence and regulation of the refractory period in the gonadal and fat cycles of the junco. J. Exp. Zool. 121:311-326.
W. P E R R Y J O I N E R AND T I L L M .
HUSTON
Poultry Division, the University of Georgia, Athens, Georgia (Received for-publication March 25, 1957)
C
O M P A R A T I V E L Y little information has been published to indicate breed differences in growth responses of domestic fowl to high environmental temperatures. I t is generally recognized t h a t the growth rate of domestic fowl exhibits seasonal variations and t h a t environmental temperature is an influencing factor in this variation. There is considerable evidence t h a t the growth rate of chickens is retarded during the hot summer months. Heywang (1947) reported t h a t White Leghorn and Rhode Island Red chicks grown in a cooled house during the hot summer months weighed more than those grown in an uncooled house. Kempster (1938) found t h a t high summer temperatures depressed growth and the difference became more pronounced as the age of the birds increased. KheirEldrin and Shaffner (1954) exposed growing birds to extremely high environmental temperatures for short periods of time and depressed the growth rate. They observed 1 Journal Series Paper No. 40, College Agricultural Experiment Station, University of Georgia, Athens, Georgia. 2 Supported in part by a research grant from the American Poultry and Hatchery Federation.
t h a t families which had the highest growth rate were best able to withstand the treatment a n d concluded t h a t heat tolerance is genetically influenced. H u t t (1938) studied breed differences in susceptibility to extreme heat and found t h a t the White Leghorn hens live and perform better a t high environmental temperatures than either the Rhode Island Red or White P l y m o u t h Rock hens. Kleiber and Dougherty (1934), and Winchester and Kleiber (1938) showed t h a t when immature fowl is exposed to a cold environment, it responds by increasing oxygen consumption. Hoffm a n n and Shaffner (1950) showed t h a t immature fowl held in a cool environmental temperature had heavier thyroid glands and elaborated more thyroxine t h a n those exposed to high temperatures, demonstrating a positive relationship between thyroid weight a n d function. Hoffmann (1950) showed t h a t the growth p a t t e r n of the duck is correlated with app a r e n t thyroxine secretion rate. I t has been shown (Winchester, 1940) t h a t the thyrotropic hormone content of the pituitary is highest during the periods of greatest h e a t production. This indicates
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The Influence of High Environmental Temperature on Immature Domestic Fowl1-2
Oregon Agricultural Experiment Station, Corvallis (Received for publication March 18, 1957)
T
LITERATURE REVIEW
The egg production patterns of a seasonal and year to year nature for turkeys have been reported by Asmundson and Lloyd (193S) and Marsden (1936). Asmundson (1941) found that, with Bronze turkeys selected for early maturity, it is possible to obtain more eggs during the breeding season and throughout the year. Egg production of Beltsville Small White turkeys was reported by 1
Technical Paper No. 1034, Oregon Agricultural Experiment Station. Supported in part by a grant from the National Turkey Federation.
Knox and Marsden (1954) to be improved by use of selection based on trapnest records and an increase was obtained of 79.6 to 146.2 eggs per hen from January 1 to October 1, during the period from 1944 to 1951. As a general observation turkey breeding flocks fail to produce eggs at a satisfactory rate during the summer months. This appears to be especially true for young hens hatched in the late fall and winter months that normally would reach sexual maturity in seven or eight months (Harper, 1955). While the cause for a low rate of production is not known there is evidence available, from other species of birds indicating that light plays an important role. The effect of light in stimulus and control of the reproductive activity of plants and animals has been the subject of numerous investigations. Much of the early work with the avian species has been reviewed by Bissonnette (1936). Benoit (1938) in experiments with ducks observed the stimulating effect of light on the optic nerve and linkage with activity of the hypophysis. The effectiveness of artificial light to stimulate turkey hens to lay earlier during periods of short day length was demonstrated by the Nebraska Agricultural Experiment Station (1930) and Albright and Thompson (1933). The influence of age of turkeys and effect of light on production has been reported by Margolf, Harper and Callenbach (1947). More recently Asmundson and Moses (1950) investigated the influence of day length on egg produc-
967
Downloaded from http://ps.oxfordjournals.org/ at UNIVERSITY OF PITTSBURGH on June 3, 2015
HE turkey industry has operated largely on a seasonal basis and little attention has been given to out-of-season production until the recent interest in marketing of turkey broilers. While the seasonal nature of turkey production may be attributed partly to holiday demands, weather limitations in some areas of production and the normal breeding cycle of turkeys, there is little reason to believe the pattern of production cannot be altered. There are at least two possible approaches to the problem of obtaining eggs from turkey hens for hatching purposes throughout the year. One of these is by means of genetic selection to gain persistency of egg production as has been followed by chicken breeders. The second is through possible changes in environment of young hens hatched out-of-season or yearling hens that have completed several months of lay. The second approach has been used in experiments reported herein.
968
J. A. HARPER AND J. E. PARKER
8 hour day length from 14 or 16 to the 28 or 30th week of age, then exposed to a 14 hour light day. PROCEDURE
Experiments with young hens {1953).— A group of 50 range-reared Beltsville Small White hens hatched February 18, 1953 were assorted at random and placed in 5 pens when 23 weeks of age on August 1. The treatments were as follows: 10 hens kept in an outside yard with a shelter; the 40 remaining were kept in pens of 10 each in a wire sided pole house and these four pens were restricted to 9 hours of light each day for 0, 7, 14 and 21 days. The hens on restricted light were driven into dark pens at 5:00 p.m. each day and released to pens with natural light at 8:00 a.m. the following morning. The hens in the outside yard and two pens in the pole house receiving 0 and 7 days restricted light were provided with a total of 17 hours of light per day on August 8. On August 15 and 22 the 14 and 21 day restricted light pens, respectively, were also provided with 17 hours of total light daily. (1954)—A group of 90 Beltsville Small White hens hatched in November 1953 were managed together in a brooder house to 15 weeks of age and range reared to June 1, 1954, when 27 weeks of age. Three pens of 30 hens each were assorted at random and moved to pens of the pole house. The control pens were maintained under natural daily light for four weeks. The other two pens were restricted to a 9 hour daily light period from June 1 to either June 15 or 29. The three pens were then provided with a daily light period totaling 17 hours after the treatments of 0, 14 and 28 days of restricted light. (1956)—A group of 120 Beltsville Small White hens hatched on December 13 and 27, 1955, were brooded to March 1
Downloaded from http://ps.oxfordjournals.org/ at UNIVERSITY OF PITTSBURGH on June 3, 2015
tion and concluded that a total daily light period of 13-15 hours was about optimum. The experiments with turkeys cited above were conducted in periods of short natural day length when the stimulation from light would be most effective. In other avian species it has been postulated that following a period of gonadal stimulation induced by long day lengths there is a refractory period during which further increases in daily light does not evoke further gonadal development. Short daily light periods, are required to end the refractory period according to Damste (1947) and Wolfson (1952). Kirkpatrick and Leopold (1952) in experiments with quail concluded that night or dark periods exert a specific influence on photoperiodic response. Farner, Mewalt and Irving (1953) working with sparrows using light exposure at 10, 12.2, 18 and three other 10 hour groups with light interruption of dark periods, found equal stimulation of gonads from 18 hours of continuous light and 10 hours interrupted by nine periods of 1.11 hours of darkness. Piatt (1955) reported that White Leghorn pullets hatched in January, maintained on a regular day length or restricted to an 8 hour day length at three months of age, followed by a 14 hour day length on August 28, laid at a higher rate when coming into production if lighting had been restricted. Hutchinson (1956) reared Brown Leghorn pullets from 8 weeks of age through the second month of lay on either a daily light exposure of 12 or 2 3 | hours per day. Following the two months production period light was gradually reduced for the latter group to 16 hours per day. It was observed that egg production declined and a molt occurred. With turkeys hatched at different seasons of the year Marr el al. (1956) observed better subsequent egg production from hens hatched in January subjected to an
SEASONAL EGG PRODUCTION OF TURKEYS
969
TABLE 1.—Effect of reducing daily light for varying intervals on subsequent egg production of Beltsville Small White turkeys (1953—10 young hens per pen) Egg production—Percent hen days uigiil. u c a i u i c u i
Range Confined Confined Confined Confined
Natural Natural 9 hrs. 9 hrs. 9 hrs.
8/1 8/1 8/1 8/1 8/1
17 hrs. 17 hrs. 17 hrs. 17 hrs. 17 hrs.
8/8 8/8 8/8 8/15 8/20
Sept.
Oct.
Nov. 20
Mean 1
31.0 14.2 15.2 38.1 40,6
24.5 37.1 42.6 48.1 51.6
17.5 26.0 29.5 34.0 53.0
25.2 26.0 29.4 40.1 48.4
in confinement and range reared to June 1 when 22 or 24 weeks of age. The hens were then allotted at random into six pens of 20 hens each, with three pens maintained thereafter in the pole house and three pens in outside yards. Sub-groups under each management conditions were maintained under natural light, restricted to a 9 hour day length for 4 weeks or injected intramuscularly with 40 or 80 milligrams of progesterone. The three pens in the pole house were exposed to a 17 hour total daily light period starting June 29. The hens in outside yards were maintained under prevailing natural light to the end of the experimental period on November 14, 1956. Experiments with Yearling Hens (1955). —Two groups of 40 Beltsville Small White and 40 crossbred white (F2 BBB XBSW) turkey hens completing six months of lay to June 22 were divided into duplicate pens of 10 hens each according to origin. The duplicate pens were either restricted to a 9 hour day length for four weeks or force molted by removal of water for 24 hours and feed for 36 hours. The hens were maintained in the pole house and subjected to a 17 hour day length on July 21. (1956)—A group of 39 crossbred white (F 3 BBB XBSW) hens completing six months of lay to June 1 were divided
equally in 3 pens. The hens were managed in the pole house. One pen was maintained to August 1 on natural light. A second pen was force molted by intramuscular injection of 40 mg. of progesterone per bird on June 1. The hens in the third pen were restricted to a 9 hour day length from June 1 to 28. All hens were provided with 17 hours of light per day beginning August 1. RESULTS AND DISCUSSION
The results of the experiment with young Beltsville Small White hens in 1953 are shown in Table 1. Egg production of the hens on range or in confinement and provided 17 hours of light per day averaged 25.2 and 26.0 percent from September 1 to November 20. The pens restricted to a 9 hour day length for 1, 2 and 3 weeks and subsequently subjected to 17 hours of light stimulation averaged 29.4, 40.1 and 48.4 percent, respectively. Both trapnest records and examination of oviducts of hens in non-restricted light pens showed that only five birds in each were in production. It would appear that turkey hens reared during periods of long day length, as were the control groups, are refractory to additional light as reported for other avian species by Damste (1947) and Wolfson (1952) and become responsive when subjected to a two or
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!L.S.D. (.05) = 21.7. L.S.D. (.01) = 29.1.
970
J. A. HARPER AND J. E. PARKER TABLE 2.—Effect of reducing daily light for varying intervals on subsequent egg production of Beltsville Small White turkeys (1954—30 young hens per pen) Egg production—Percent hen days
Natural 6/1 9 hrs. 6/15 9 hrs. 6/1 1
17 hrs. 6/29 17 hrs. 6/29 17 hrs. 6/29
June 14
July
Aug.
Sept.
Oct. 28
Mean 1
35.2 12.5 11.9
46.2 26.8 28.8
38.7 34.5 59.7
42.9 46.7 54.7
38.2 42.1 53.7
36.8 31.0 40.3
L.S.D. (.05)= 8.33. L.S.D. (.01) = 11.04.
on egg production recorded in Table 2 show the suppression of laying during June and July for the restricted light hens as compared to the control pens. Following stimulation by light the hens that had been on restricted light laid at a higher rate than the hens maintained on natural light. In 1956 the 120 young Beltsville Small White hens were subjected to treatments as outlined previously on June 1 when they were 22 or 24 weeks of age. The results of this experiment are shown in Table 3. Use of progesterone to force molt the hens prior to laying was tried since it had been noted that restricted lighting in previous years induced a partial molt. Further it was realized that if molt was associated with subsequent egg production, and the same effect could be obtained with progesterone as with restricted light-
TABLE 3.—Effect of reducing light and progesterone injection on subsequent egg production on Beltsville Small White turkeys (1956—20 young hens per pen) Egg production—Percent hen days July
Aug.
Sept.
Oct.
Nov.
Means 1
Confined Confined Confined
Natural 6/1 Prog. 80 mg. 6/1 6 hrs. 6/1
17 hrs. 17 hrs. 17 hrs.
6/29 6/29 6/29
18.2 0.0 21.3
19.5 6.4 66.5
23.8 19.6 62.0
19.5 29.5 55.0
25.9 42.1 44.5
20.7 15.9 50.5
Range Range Range
Natural 6/1 Prog. 40 mg. 6/1 9 hrs. 6/1
Natural 6/1 Natural 6/1 Natural 6/29
11.6 1.8 19.0
20.6 4.8 63.4
13.7 9.3 45.6
16.1 10.0 17.1
11.8 12.3 3.6
15.2 6.9 33.5
1
L.S.D. (.05) = 10.7. L.S.D. (.01) = 14.2.
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three week period on a nine hour day length prior to laying. In 1954 the three pens of young Beltsville Small White hens were 27 weeks of age at the time when subjected to treatments of 0,14 or 28 days of restricted light on June 1. The results of this experiment are shown in Table 2. Egg production on a hen-day basis averaged 36.8, 31.0 and 40.3 percent, respectively. The rate of lay was in this year higher for the non-restricted light hens than in 1953 and the differences between treatments not very large. The highest rate of lay, however, was still in favor of the turkey hens subjected to 4 weeks of restricted light. Some hens were in production at the time restricted light treatments were imposed and subsequently ceased laying. These hens required a longer period to return to lay. The effects of the various treatments
SEASONAL EGG PRODUCTION OF TURKEYS
TABLE 4.—Effect
Experiments with yearling hens having completed 6 months of lay were directed toward determining if an efficient rate of production could be obtained following force molting or restriction to a short day length. In 1954, four weeks following force molting by starvation or subjection to a 9 hour day length, the hens were exposed to a total of 17 hours of light daily. As shown in Table 4 during the following months from August to November 20, the hens laid at a rate of from 6.7 to 20.3 percent. In 1956, the yearling hens were maintained after June 1 on natural light, subjected to 9 hours of light per day for four weeks or given 40 mg. of progesterone. In contrast to the previous year a period of eight and one-half weeks "rest" was provided instead of four weeks. The results are shown in Table 5. The percentage rate of lay was 2.2, 13.1 and 1.5 for the three pens, respectively. While being higher in the restricted light pen than the other two groups, the rate of lay was very low. Shell quality of eggs laid by all yearling hens was poor. It is clear that under the various regimes used in both years for yearling hens the rate of lay was too low to maintain hens for a second period of hatching
of a reduction in daily light period or force molting by starvation on subsequent egg production of yearling turkeys (1955—10 hens per pen) Egg production —Number per pen
Variety
Light tr eatment
%
Aug.
Sept.
Oct.
Nov. 28
Total
Hen day basis
B.S.W. B.S.W. B.S.W. B.S.W.
9 hrs. 9 hrs. Starvation* Starvation*
6/22 6/22 6/22 6/22
17 17 17 17
hrs. hrs. hrs. hrs.
7/20 7/20 7/20 7/20
18 21 0 9
48 30 0 38
55 51 38 56
123 118 135 63
244 210 173 166
20.3 17.5 14.4 13.8
X-Bred X-Bred X-Bred X-Bred
9 hrs. 9 hrs. Starvation Starvation
6/22 6/22 6/22 6/22
17 17 17 17
hrs. hrs. hrs. hrs.
7/20 7/20 7/20 7/20
3 1 1 0
10 18 11 12
14 31 23 67
65 31 62 128
92 81 97 207
7.7 6.7 8.1 17.2
* Water removed 24 hours and feed 36 hours.
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ing, there would be a possibility of wider application under commercial conditions of breeder hen management. The rate of lay for hens maintained in the pole house and subjected to a 17 hour day length following 0 to 4 weeks on a 9 hour daily light period averaged 20.7 and 50.5 percent, respectively. The hens treated with 80 mg. of progesterone underwent a heavy molt and until October remained below the control group in production. The three pens of hens maintained in outside yards with natural light after restricted light treatments followed a pattern of production in July and August similar to those on the 17-hour day length. In September and later months the effect of decreasing natural light resulted in lower egg production in all groups as compared with that of similar pens in the pole house. The pens treated with 40 mg. of progesterone molted as completely as the hens receiving 80 mg. of the hormone. At these levels progesterone caused a delay in production and not an earlier and greater response as has been reported by Nalbandov (1956) to occur with chickens injected with a 25 mg. level of progesterone prior to production.
971
972
J. A. HARPER AND J. E. PARKER TABLE 5.—Effect
of a reduction in daily light period, force molting or progesterone on subsequent egg production of yearling turkeys (1956—13 hens per pen) Egg production—Number per pen
Light treatment
Natural 6/1 9 hrs. 6/1 to 6/28 40 mg. Prog. 6/1
17 hrs. 8/1 17 hrs. 8/1 17 hrs. 8/1
%
July
Aug.
Sept.
Oct.
Nov.
Total
Hen day basis
36 46 4
0 94 0
0 38 0
0 42 17
0 16 2
36 236 23
2.2 13.1 1.5
SUMMARY Young Beltsville Small White turkey hens hatched in the winter months were found to lay at a low rate and showed evidence of being refractory to stimulation by two additional hours of light beyond the natural light of summer months. Young hens restricted to 9 hours of light per day when 22 or 24 weeks of age for a 3 or 4 week period produced eggs at a level of approximately 50 percent when exposed to the natural daily light length of summer months or by use of artificial lighting to provide 17 hours of total daily light. Egg production of these hens declined in September and later months unless the natural light hours were extended by artificial light. Progesterone at levels of 40 and 80 milligrams per young hen caused a heavy molt and egg production was depressed as compared to restricted or non-restricted light pens. Yearling hens force molted by starvation, progesterone or restriction to a 9 hour daily light length for 4 weeks, fol-
lowed by exposure to a 17-hour day length immediately or four and one-half weeks later, did not produce eggs at a satisfactory rate. REFERENCES Albright, W. P., and R. B. Thompson, 1933. Securing early turkeys by stimulated egg production. Poultry Sci. 12:124-128. Anonymous, 1930. Turkey production. Nebraska Agri. Exper. Sta. Ann. Report p. 39. Asmundson, V. S., 1941. Differences in sexual maturity and egg production in turkeys. Poultry Sci. 20: 51-56. Asmundson, V. S., and B. D. Moses, 1950. Influence of length of day on reproduction in turkey hens. Poultry Sci. 29: 34-41. Asmundson, V. S., and W. E. Lloyd, 1935. The effect of age on reproduction of the turkey hen. Poultry Sci. 14: 259-265. Benoit, J., 1938. Role des ycux et de la voie nerveuse oculo-hypophysaire dans le gonadostimulation par la lumiere artificielle chex le canard domestique. Compt. Rend. Soc. Biol. 129: 231-234. Bissonette, T. H., 1936. Sexual photoperiodicity. Quarterly Review of Biol. 371-386. Damste, P. H., 1947. Experimental modification of the sexual cycle of the green finch. J. Exp. Biol. 24: 20-35. Farner, D. S., L. R. Mewalt and S. D. Irving, 1953. The role of darkness and light in activation of avian gonads. Science, 118: 351-352. Harper, J. A., 1955. You can get hatching eggs the year 'round. Turkey World, 30: 17. Hutchinson, J. C. D., 1956. Control of seasonal variation in the egg production of hens. Nature, 177:795-796. Kirkpatrick, C. M., and A. C. Leopold, 1952. The role of darkness in sexual activity of quail. Science, 116: 280-281. Knox, C. W., and S. J. Marsden, 1954. Breeding for increased egg production in Beltsville Small
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egg production. Whether or not providing the hens with a longer rest period following a period of production would result in better egg production is open to question. The economy in maintaining the yearling hens as balanced against replacement with young hens having a potential of a higher rate of production would be an important consideration.
SEASONAL E G G PRODUCTION OF T U R K E Y S
White turkeys. Poultry Sci. 33:443^447. Margolf, P. H., J. A. Harper and E. W. Callenbach, 1947. Response of turkeys to artificial insemination. Pennsylvania Agri. Exper. Sta. Bui. 486. Marr, J. E., F. W. Garland, Jr., J. L. Milligan and H. L. Wilcke, 1956. Effect of controlled light during the growing period upon subsequent performance of breeder turkeys. Poultry Sci. 35:1156. Marsden, S. J., 1936. A study of egg production in
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bronze turkeys. Poultry Sci. 15: 439-445. Nalbandov, A. V., 1950. Effect of progesterone in egg production. Poultry Sci. 35:1162. Piatt, C. S., 1955. A study of the effect of restricted lighting on January hatched pullets. Poultry Sci. 34: 1045-1047. Wolfson, A., 1952. The occurrence and regulation of the refractory period in the gonadal and fat cycles of the junco. J. Exp. Zool. 121:311-326.
W. P E R R Y J O I N E R AND T I L L M .
HUSTON
Poultry Division, the University of Georgia, Athens, Georgia (Received for-publication March 25, 1957)
C
O M P A R A T I V E L Y little information has been published to indicate breed differences in growth responses of domestic fowl to high environmental temperatures. I t is generally recognized t h a t the growth rate of domestic fowl exhibits seasonal variations and t h a t environmental temperature is an influencing factor in this variation. There is considerable evidence t h a t the growth rate of chickens is retarded during the hot summer months. Heywang (1947) reported t h a t White Leghorn and Rhode Island Red chicks grown in a cooled house during the hot summer months weighed more than those grown in an uncooled house. Kempster (1938) found t h a t high summer temperatures depressed growth and the difference became more pronounced as the age of the birds increased. KheirEldrin and Shaffner (1954) exposed growing birds to extremely high environmental temperatures for short periods of time and depressed the growth rate. They observed 1 Journal Series Paper No. 40, College Agricultural Experiment Station, University of Georgia, Athens, Georgia. 2 Supported in part by a research grant from the American Poultry and Hatchery Federation.
t h a t families which had the highest growth rate were best able to withstand the treatment a n d concluded t h a t heat tolerance is genetically influenced. H u t t (1938) studied breed differences in susceptibility to extreme heat and found t h a t the White Leghorn hens live and perform better a t high environmental temperatures than either the Rhode Island Red or White P l y m o u t h Rock hens. Kleiber and Dougherty (1934), and Winchester and Kleiber (1938) showed t h a t when immature fowl is exposed to a cold environment, it responds by increasing oxygen consumption. Hoffm a n n and Shaffner (1950) showed t h a t immature fowl held in a cool environmental temperature had heavier thyroid glands and elaborated more thyroxine t h a n those exposed to high temperatures, demonstrating a positive relationship between thyroid weight a n d function. Hoffmann (1950) showed t h a t the growth p a t t e r n of the duck is correlated with app a r e n t thyroxine secretion rate. I t has been shown (Winchester, 1940) t h a t the thyrotropic hormone content of the pituitary is highest during the periods of greatest h e a t production. This indicates
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The Influence of High Environmental Temperature on Immature Domestic Fowl1-2