CC BY
56
UDC 636.5053.03:628.977.1:631.227.22
EFFICIENCY OF USAGE OF DIFFERENT LIGHTING PROGRAMS IN BROILER POULTRY
Buyarov V.S., Doctor of Agricultural Sciences Balashov V.V., Post-graduate student Orel State Agrarian University, Orel City, Russia E-mail: bvc5636@mail.ru
ABSTRACT
In the course of scientific experiments the influence of investigated programs of lighting on zootechnical indicators of broiler growing and carcass traits was defined. The lighting program for batch chickens growing was used. It is quite different at fattening of big broilers. It is proved that the lighting program influences on viability and productive qualities of broilers of cross «Ross-308». The developed lighting programs usage at broiler chickens growing in poultry farm conditions provided the increase of economic efficiency, the increase of poultry meat production profitability by 2,96% - at growing big broilers and by 1,61% - at batch chickens fattening.
KEY WORDS
Chicken broilers; Lighting programs; Growing efficiency.
Increase of broilers meat production efficiency is possible only at implementation of the most recent energy saving processing technologies; one of them is rational lighting program in poultry house. That is why the development of new programs of lighting and improvement of already functioning ones is one the objectives of high priority for scientists and practitioners [1, 4, 6, 7, 8, 11, 13, 14].
Nowadays at chicken broilers growing to provide their high productivity and viability the great number of different lighting modes for example continuous, alternative, pulsed, rhythmically variable are developed and successfully used [2, 10, 12, 15, 17, 20, 21, 23, 24, 25].
In recent years the usage of energy saving modes and systems of lighting at poultry growing comes to the foreground. Their application positively influence on the production profitability. The lighting programs provide the control of broilers fattening and are the main factor to obtain high results. Evaluated and successfully proved themselves lighting modes are not panacea for all broiler enterprises. The lighting program should be chosen according to special features of technology of poultry growing (cross, in cages or on nest cushion, fattening period, etc.). The majority of lighting programs are developed for middle type broilers growing. (fattening period 38-42 days) [7, 8, 9, 18, 19, 22].
New direction of broilers production is growing of broilers of three types depending on consumer demand (small - to fry as a whole, middle and large - to dress and advanced processing). We developed technology of growing broilers of different weight category: with live weight to 1,5 kg (i.e. with carcass mass in the range of 1 kg - chicken of «batch type»); live weight from 1,7 to 2 kg (with carcass mass 1,2-1,4 kg - «middle» type) and large broilers production with carcass mass more than 2 kg [16]. The most important element of this technology is the lighting program for broilers [3, 5]. In reference with the above the relevant objective of the broiler poultry is development and successful implementation of lighting modes adapted to growing of chicken broilers of perspective crosses and different weight categories.
The work objective was to study efficiency of the lighting programs for chicken broilers of cross «Ross-308» with different growing period in cages and on nest cushion.
To achieve the objective the following targets were put and solved: to develop effective lighting program for large broiler cockerels growing (fattening period - 55 days); to develop effective lighting program for batch broilers chickens growing (fattening period - 35 days); to
define the degree of influence of the developed lighting programs on the productive qualities of chicken-broilers.; to do production evaluations of the developed lighting programs and calculate economy efficiency of their application at chicken-broilers growing.
MATERIALS AND METHODS OF RESEARCH
The research was done at the poultry meat production enterprise CJSC of Agro Industrial Complex «Orlovskaya Niva» and poultry farm LLC «Orlovskye zory». Chickens-broilers of cross «Ross-308» were considered as an object of research. Poultry fattening was done with full ration granulated mixed feeds with the composition of all the necessary nutrients according to standards and recommendations of All Russian Research and Technological Institute of Poultry for this cross. Housing conditions (except the lighting modes) were equal for all groups.
Table 1 - Lighting modes (test № 1)
Age, days | Lighting, lk | Lighting, h
Standard mode of lighting, used at poultry farm (control group)
0-6 30 23C:1T
8-52 30 ^ 10 Gradual decrease 20C:4T
53-55 10 ► 5 Gradual decrease 23C:1T
Lighting mode for the first experimental group
0-7 30 23C:1T
8-21 30 10 Gradual decrease 18C:6T
22-52 10 20C:4T
53-55 10 ». 5 Gradual decrease 23C:1T
Lighting mode for the second experimental group
0-7 30 23C:1T
8-14 30 ^ 10 Gradual decrease 18C:6T
15-24 10 (4C:4T)*3
25-29 10 18C:6T
30-52 10 ¥ 5 Gradual decrease 20C:4T
53-55 5 23C:1T
Lighting mode for the third experimental group
0-7 30 23C:1T
8-14 30 10 Gradual decrease 18C:6T
15-24 10 (6C:6T)*2
25-29 10 18C:6T
30-52 10 ^ 5 Gradual decrease 20C:4T
53-55 5 23C:1T
Before catching in 24-48 h increase lighting to 20 lk
The lighting system «Gasolec» in configuration with green spectrum lamps (with wave length 520-560 nm) was used at poultry growing. In every of the experimental poultry houses 4 lighting lines were mounted (72 green light lamps in each). One lamp capacity was 11 W. The lamp and adapter consume maximally 13 W/h. More than that in every poultry house there were 2 lines of technical lighting (conventional filament lamps of capacity 60 W). All lines were switched on before the 7-th day of growing in the poultry houses. After the 7-th of growing day 2 technical lines switched off and 4 lines of the green light lamps remained on. At the end of the 10-th day of broilers growing in all experimental poultry houses only 3 lines of the green light lamps remained on The programmed time relay (timer) «nMK-2n» was used for pulsed modes application.
The first test objective was to study the influence of different lighting modes on the productive indicators of «large» broiler chicken cockerels of cross «Ross-308», which were grown on nest cushion from one-day old to 55-day old age and reaching live weight 3,5-3,7 kg. The lighting programs presented in Table 1 were applied at broilers growing. All lighting programs provided long day light (23C:1T) on different stages of growing to the age of 7 days. In the second experimental group in the period from the 15-th to 24-th day of life lighting program 12C:12T (4C:4T)*3 was applied. In the third experimental group from the period from 15-th to 24-th day of life lighting program 12C:12T (6C:6T)*2 was applied. The lighting intensity in all groups was similar and corresponds to 30 lk during the first week. And then it decreases gradually to 10-5 lk.
In the second test the research objective was to study the influence of different lighting modes on productive indicators of chickens of batch type of cross «Ross-308», which ere grown in cage batteries Kn-8.n during 35 days (with early slaughtering periods at gaining live weight 1,7-1,8 kg). At broilers growing the lighting programs presented in Table 2. In the control group the standard mode of continuous lighting during 23 hours per day with one hour of darkening was used. In the first experimental group the mode of pulsed lighting from the 7-th to the 28-th day of life was used according to scheme: 3C:1T. In the second group the pulsed lighting mode from the 7-th to the 28-th day of life was used according to scheme: 5C:1T. The lighting efficiency in all groups was the same. The number of broilers in each group in all scientific and economic tests was 50 birds.
Table 2 - Lighting modes (test № 2)
Age, days | Lighting, lk | Lighting, h
Standard lighting mode, used in poultry farm (control group)
0-6 20 23C:1T
7-21 20 ¥ 10 Gradual decrease 23C:1T
22 and older 10 23C:1T
Lighting mode for the first experimental group
0-6 20 23C:1T
7-28 20 ^ 10 Gradual decrease (3C:1T)*6
29-35 10 23C:1T
Lighting mode for the second experimental group
0-6 20 23C:1T
7-28 20 + 10 Gradual decrease (5C:1T)*4
29-35 10 23C:1T
Before catching in 24-48 h increase lighting to 20 lk
After the end of tests the industrial verifications were carried out. In the first test (chickens broilers were grown on nest cushion to the 55-days age): the standard lighting program was used in the control group. In the experimental group the pulsed lighting mode (4C:4T)*3 in the period from the 15-th to the 24-th day of life (see the lighting program for the second experimental group in Table 1) was used. The number of chickens in groups was 14580 birds.
In the second test chickens broilers of batch type were grown in cage batteries of type Kn-8.n during 35 days. As in the previous variants the standard lighting mode was used in the control group, the program of pulsed lighting 3C:1T from the 7-th to the 28-th day of life was used in the experimental group (see the lighting program for the first experimental group in Table 2). In both groups the poultry population of the experimental chickens broilers was 32400 birds.
At carrying out scientific tests the following indicators were defined:
1. Zootechnic. Live weight was defined by means of individual weighting of chickens broilers of each group at 29 days and at the end of growing. According to the universally accepted formula the daily average live weight gain was calculated. The poultry population safety during the test period was maintained by means of accounting of drop out poultry with
definition of withdrawal reasons. A fodder expense for 1 kg of live weight gain was calculated according to the data of fodder consumption and live weight accounting. European efficiency factor (broilers productivity index) was calculated by formula:
m * c
Е0Э =--------*100,
K * T
where M - average live weight (kg); C - safety (%); K - fodder expenses for 1 kg of gain (kg); T - period of growth (days).
2. Anatomic dressing was done according to methodic recommendations of All Russian Research and Technological Institute of Poultry (T.A. Stollyar and others, 1994; V. S Lukashenko and others, 2001). The mass of eviscerated carcass was defined by means of individual weighting of all broilers carcasses from each group. Slaughter output was defined by mass ratio of eviscerated carcasses to preslaughter weight in percentage. According to GOST P 52702-2006 «Chicken meat (chickens carcasses, broilers chickens and their parts)» estimated carcass grade.
3. Economic. Efficiency of the lighting programs influence - was defined by calculation method taking into account live weight indicators, daily average gain, fodder conversion, poultry safety, European efficiency factor, slaughter output, power costs for lighting, energy costs.
4. Statistic analysis of the data obtained was done by PC using the programs «Microsoft Excel» (2003) and «Statistica».
RESULTS AND DISCUSSION
Lighting programs efficiency used at large chicken broilers-cockerels (test № 1). As the result of scientific test it was proved that the zootechnical indicators of floor stand growing of chicken broilers (cockerels) of cross «Ross-308» are influenced by the lighting program in experimental poultry houses (Table 3). The data analysis showed that at the age of 55 days the maximum high live weight was typical for the chickens of experimental group 2, and according to this indicator they surpassed their counterparts from control by 5,24% (P<0,001), group 1 - by 3,77% (P<0,001), group 3 - by 2,65% (P<0,01). Average live weight of broilers of experimental group 1 was by 1,42%, broilers of group 3 - by 2,52% (P<0,05) higher than of their counterparts from control group. With increase of live weight the daily average gains increased too correspondingly.
Table 3 - Zootechnical indicators of large chicken broilers (cockerels) of cross «Ross-308»
at different lighting programs (M±m)
Indicators Group
control 1 - experimental 2 - experimental 3 - experimental
Poultry population 50 50 50 50
Live weight 1 bird. at 29 days, g 1810,6±23,1 1874,3±24,7 2010,8±24,1*** 1995,9±25,7***
Live weight 1 bird. at 55 days, g 3552,6±27,0 3603,1±23,6 3738,9±20,8*** 3642,2±25,0*
Daily average gain, g 63,7 64,6 67,1 65,3
Fodder expense for 1 kgr of live weight gain , kg 2,21 2,15 1,95 2,09
Safety, % 94,0 96,0 98,0 96,0
European efficiency factor, units. 275 293 342 304
Note: * - P<0,05; *** - P<0,001.
During the period of growing the fodder expenses per unit of for live weight gain in experimental group 2 were lower than in the control group by 11,76%, and in group 1 were by 2,72% and in group 3 - by 5,43%. At the extend term of broilers growing the final output is greatly influenced with poultry population safety. The chickens of experimental group 2 had maximum viability in our research. For the fattening period the poultry safety index of this
group surpassed the control value by 4%. European efficiency factor in the experimental groups was 293-342 units; the difference between the control and experimental group 2 was maximum - 67 units (24,36%).
The results of the research (Table 4) showed that the maximum meat output in the eviscerated state was in the second experimental group of broilers and was 73,5%. It was proved that the chickens from the second group had the best meat qualities according to the broilers carcasses morphological composition All muscle output of broilers carcasses was maximum in the second group cockerels - 65,72%, that is by 3,32%, 2,52% and 1,2% more than in the control, the first and the third groups correspondingly. The maximum output of edible parts in a eviscerated carcass (mostly at the expense of greater output of muscles) was in experimental groups 2 and 3 - 83,73% and 83,41% correspondingly. Large broilers carcasses of cross «Ross-308» are suitable for dressing and advanced processing best of all.
Table 4 - Meat qualities of chickens broilers of cross «Ross-308» (age - 55 days; M±m; n=6)
Indicators Group
control 1- experimental 2 - experimental 3 - experimental
Preslaughter weight, g 3553±16,8 3612±18,8* 3737±18,2*** 3646±13,5**
Eviscerated carcass weight, g 2594,2±10,8 2639,8±10,4* 2746,5±13,1*** 2674,0±10,8***
Slaughter output, % 73,0 73,1 73,5 73,3
Muscles weight, g 1618,9±8,2 1668,5±8,0** 1805,1±11,0*** 1725,3±8,1***
incl. fillet 600,7±5,7 634,9±4,6*** 718,3±5,9*** 688,7±5,4***
Bone weight, g 437,7±2,9 435,6±2,3 440,1±2,7 437,3±3,0
Edible parts weight, g 2151,5±9,4 2198,4±9,5** 2299,9±11,6*** 2230,6±10,3***
Inedible parts weight, g 442,7±2,4 441,5±2,9 446,6±2,6 443,4±2,9
Edible / inedible parts ratio 4,86 4,98 5,15 5,03
Note: * - P<0,05; ** - P<0,01; *** - P<0,001.
Thus, on the basis of complex analysis of zootechnical indicators, broilers meat qualities we can conclude that the second experimental group possessed the best growth rates at high safety and food conversion, more optimal morphological and chemical carcasses composition. In connection with it at the floor management growth of large broiler chickens (cockerels) before achieving live weight 3,5-3,7 kg at the age of 55 days by them it is recommended to use the following lighting program in the period from the 1-st to the 7-th day - 23C:1T, from the 8-th to the 14-th day - 18C:6T, from the 15-th to the 24-th day -(4C:4T)*3, from the 25-th to the 29 -th day - 18C:6T, from the 30-th to the 52-th day - 20C:4T and from the 53-th to the 55-th day of life - 23C:1T.
Efficiency of the lighting programs used at batch chickens broilers growing (test № 2). It is supposed that in the future the development of the financial crisis and consumers’ preference and behavior change can result in some decrease in broiler average weight and reduce of the poultry growth period. The research proved that that the best from the zootechnical point of view is the lighting mode applied at growing broilers of experimental group 1.
Table 5 - Zootechnical indicators of growing chickens broilers of cross «Ross-308» at different lighting programs (M±m)
Indicators Group
control 1- experimental 2 - experimental
Poultry population 50 50 50
Live weight of 1 unit at 29 days, g 1266,4±18,4 1375,5±18,2*** 1315,2±23,5
Live weight of 1 unit at 35 days, g 1758,8±19,2 1857,1±18,2*** 1801,6±19,5
Daily average gain, g 48,8 51,6 50,0
Fodder expense for 1 kgr of live weight gain, kg 1,80 1,76 1,78
Safety, % 94,0 98,0 94,0
European efficiency factor, units 262 295 272
Note: *** - P<0,001.
Broilers live weight of the given group at the age of 35 days corresponded to 1857, 1 g, that is by 5,59% (P<0,001) and by 3,08% (P<0,05) more than in the control group and in experimental group 2 (Table 5). The daily average gain of the chickens broilers in experimental group 1 was by 3,20% and 5,73% more than in experimental group 2 and in the control group. The best food conversion efficiency by the production was found in the chickens of experimental group 1 and corresponded to 1,76 kg, that was by 2,23% lower than in the control group. The broilers availability data affirm that the best safety was observed in the chickens of experimental group 1. European efficiency factor in experimental groups was by 23-33 units higher than on the control group, the maximum factor was obtained in the 1-st experimental group of broilers - 295 units.
Control slaughter of broilers in the experimental groups (Table 6) showed that the eviscerated carcass weight of chickens of experimental group 1 was higher by 6,25% (P<0,001) and by 3,27% (P<0,001) in comparison with the control and experimental group 2. The carcasses meat qualities estimated by the results of anatomic dressing, were high. In the chickens broilers carcasses of experimental group 1 in comparison with the control and experimental group 2 the amount of muscular tissue was more by 7,32% (P<0,001) and 3,70% (P<0,01) correspondingly. The maximum output of the edible parts in eviscerated carcass of broilers was in experimental group 1 - 1087,7 g (81,1%), that was by 7,58% (P<0,001) and by 3,59% (P<0,01) higher than in the control group and experimental group 2. The ratio of edible parts of carcass to inedible parts in the control group corresponded to 4,02, in experimental group 1 - 4,29, in group 2 - 4,22, and ratio of muscles weight to bones weight was (meat-bone index) - 3,06; 3,27; 3,21 correspondingly.
Table 6 - Meat qualities of chicken broilers of cross «Ross-308» (age - 35 days; M±m; n=6)
Indicators Group
control 1 experimental 2 experimental
Preslaughter weight, g 1757±13,5 1858±14,6** 1805±12,2*
Eviscerated carcass weight, g 1262,5±7,74 1341,5±6,61 *** 1299,0±6,86**
Slaughter output, % 71,9 72,2 72,0
Muscles weight, g 764,6±5,3 820,6±5,9*** 791,3±5,0**
incl. fillet 254,4±2,6 290,0±3,2*** 268,8±2,7**
Bone weight, g 249,1±2,3 250,9±2,1 246,5±2,5
Edible parts weight, g 1011,0±6,4 1087,7±6,3*** 1050,0±6,2**
Inedible parts weight, g 251,5±1,9 253,8±2,4 249,0±2,5
Edible / inedible parts ratio 4,02 4,29 4,22
Note: * - P<0,05; ** - P<0,01; *** - P<0,001.
Thus, as a result of the carried out research complex, it is proved that for batch chickens broilers fattening in cages of type Kn-8 at the age of 35-days with live weight 1,7-
1,8 kg, the usage of continuous lighting mode (23C:1T) is suitable from the 1-st to 6-th day of growth, the usage of pulsed lighting mode (3C:1T)*6 is suitable from the 7-th to the 28-th day of life and (23C:1T) from the 29-th to the 35-th day best of all.
The results of the production inspection proved the experimental data and showed high efficiency of the developed lighting programs at growing chickens broilers of cross «Ross-308» with different duration of fattening, allowing to increase live weight and production profitability at decrease of food expenses and production cost per production unit: at growing large broilers - by 2,40% and 2,96%; 11,66% and 2,63%, and batch chickens - by 4,50% and 1,61%;2,20% and 1,48% correspondingly. Today the production of broiler meat in new variants of growing with application of rational energy saving lighting programs has increased by 3,76-5,15% in comparison with basic variant.
Economy efficiency of large broilers (cockerels) at the age of 55-days at application of the new variant developed lighting program during one technological cycle of growing per poultry population of 14580 broilers was 60273,3 rub. At production cycle of 5,1 rotation per year the expected economic effect will be 307393,8 rub.
Economy efficiency of batch broilers growing to the age of 35-days at application of the new variant developed lighting program during one technological cycle of growing per poultry population of 32400 broilers was 34028,1 rub. At production cycle of 7,1 rotation per year the expected economic effect will be 241599,5 rub.
CONCLUSIONS
During the scientific experiments the rational lighting modes for growing large chicken broilers - cockerels - in cages and on nest cushion and of different weight categories, with live weight 3,5-3,7 kg at the age of 55 days (23C:1T) -from the 1-st to the 7-th day of fattening, (18C:6T) frm the 8-th to the 14-th day, (4C:4T)*3 in the period from the 15-th to the 24-th day, (18C:6T) from the 25-th to the 29-th day, (20C:4T) from the 30-th to the 52-th day, (23C:1T) frm the 53-th to the 55-th day; of the batch type with live weight 1,7-1,8 Kr at 35 days - (23C:1T) from the 1-st to the 6-th day of growth, (3C:1T)*6 from the 7-th to the 28-th day, (23C:1T) from the 29-th to the 35-th day of life, making positive effect on the zootechnical indicators and meat qualities of broilers of cross «Ross-308» were developed.
Application of the developed lighting programs at chicken broilers growing in the conditions of poultry farms provided increase of economic efficiency, increase of production cost of poultry meat by 2,96% - at growing of large broilers and by 1,61% - at fattening batch chickens.
REFERENCES
1. Andreev, D.S. New lighting modes for chickens broilers growing / D.S. Andreev // Author’s abstract for candidate degree in agricultural sciences. - Krasnodar. - 2009. - 22 p., il.
2. Balashov, V.V. Lighting modes and productivity indicators of broilers of cross «Ross-308» / V.V. Balashov, V.S. Buyarov // Vestnik of Orel State Agrarian University.- 2013. - № 1.
- P.103-108.
3. Buyarov, V.S. Efficiency of the lighting programs for chicken broilers with different growth period / V.S. Buyarov, V.V. Balashov // Vestnik of Orel State Agrarian University. - 2011.
- № 4. - P. 32-36.
4. Buyarov V.S. Prior directions of development of broiler poultry in the Orel region / V.S. Buyarov, I.V. Chervonova, V.V. Balashov // Zootechnics. - 2011. - № 12. - P. 22-24.
5. Buyarov, V.S. Lighting modes in the broiler production / V.S. Buyarov, V.V. Balashov, E.S. Zarubina // Innovative solutions and their acquisition in industrial poultry: materials of the XVII international conference (15-17, May, 2012). - Sergiev Posad: All Russian Research and Technological Institute of Poultry, 2012. - P. 312-316.
6. Gladin, D. Lighting is as a driver of growth / D. Gladin // Ptitseprom. - 2010. - № 4. - P. 22-24.
7. Gladin, D. LED lighting: only benefits / D. Gladin // Animal husbandry of Russia. - 2012. -№ 9. - P. 62-64.
8. Grishin, K.M. Economic justification of efficiency of application of compact fluorescent lamps and light emitting diodes in poultry / K.M. Grishin, A.K. Lyamtsov, V.V. Malyushev // Lighting technology. - 2012. - № 2. - P. 62-63.
9. Davydov, V.M. Resource saving technology of poultry production / V.M. Davydov, A.B. Maltsev, I.P. Spiridonov // Omsk: State Scientific Institution of Sib. Scientific Research Institute of Poultry. - 2004. - 352 p.
10. Zonov, M. Pulsed lighting at broilers growing / M. Zonov // Poultry. - 2009. - № 9. - P. 22-23.
11. Kavtarashvily, A.Sh. Light influence on hen physiology and productivity / A.Sh. Kavtarashvily // Private Poultry. - 2007. - № 3-4. - P. 26-28.
12. Krakosevich, T.V. Role of lighting modes at broilers growing / T.V. Krakosevich, A.A. Krakosevich // Vestnik of Russian State Agrarian Extramural University. - 2009. - № 7 (12). - P. 104-106.
13. Mailyan, E.S. Role of light in broiler poultry / E.S. Mailyan // BIO. - 2008. - № 11. - P. 9-
11.
14. Mailyan, E.S. Role of light in broiler poultry / E.S. Mailyan // BIO. - 2008. - № 12. - P. 11-13.
15. Mukhamedshina, A.R. Influence of light on poultry behavior and productivity / A.R. Mukhamedshina // Vetereinary. - 2005. - № 6. - P. 16-18.
16. Stollyar, T. Resource saving technologies of production of broilers meat / Stollyar, T., Buyarov V. // Poultry. - 2007. - № 10. - P. 9-11.
17. Trukhachev, V.I. Light in industrial poultry: practical recommendations / V.I. Trukhachev, M.F. Zonov, A.M. Yakovenko; Stavropol State Agrarian University. - Stavropol: AGRUS,
2009. - 64 p.
18. Fisinin, V.I. Technology of meat broilers production / V.I. Fisinin, T.A. Stollyar, V.V. Gushhin, V.S. Buyarov and others. // Methodical recommendations. - All Russian Research and Technological Institute of Poultry, 2005. - 252 p.
19. Fisinin, V.I. Local light emitting diodes lighting is the way of efficiency increase in poultry / V.I. Fisinin, A.Sh. Kavtarashvily, E.N. Novotorov, D.M. Gladin // Achievements of science and technique of Agro Industrial Complex. - 2011. - № 6. - P. 61-63.
20. Khaustov, V.N. Influence of some lighting modes on productive qualities and natural resistance of chicken broilers / V.N. Khaustov // Achievements of veterinary medicine of the XXI century: materials of international research / practice conference, devoted to the 40-th anniversary of Institute of computer simulation of Altay State Agrarian University. Part 2. - Barnaul: Editorial board of Altay State Agrarian University, 2002. - P. 188-190.
21. Shuganov, V.M. Broilers growing at decreased lighting using environmentally friendly additions / V.M. Shuganov // Zootechnology. - 2003. - № 10. - P. 25-26.
22. Clements, M. EU and US broiler lighting compared / M. Clements // Poultry International.
- 2009. - Vol. 48. - № 6. - p. 16-17.
23. Olanrewaju, H.A. A Review of lighting programs for broiler production / H.A. Olanrewaju // International journal of poultry science. - 2006. - № 5 (4). - P. 301-308.
24. Petek, M. The influence of different lighting programs, stocking densities and litter amounts on the welfare and productivity traits of a commercial broiler line / M. Petek, R. Cibik, H. Yildiz, F.A. Sonat, S.S. Gezen, A. Orman // Aydin Veterinarija ir zootechnika / Lietuvos veterinarijos akadimia. - Kaunas. - 2010. - T. 51(73). - P. 36-43.
25. Schwean-Lardner, K. Lighting for Broilers / K. Schwean-Lardner, H. Classen. - Aviagen,
2010. - 37 p.
