برآورد پارامترهای ژنتیکی افزایش وزن روزانه و نسبت کلیبر در گوسفندان استان گیلان

نوع مقاله : علمی پژوهشی- ژنتیک و اصلاح دام و طیور

نویسندگان

گروه علوم دامی، دانشکده علوم کشاورزی، دانشگاه گیلان

چکیده

هدف از این پژوهش برآورد پارامترهای ژنتیکی صفات میانگین افزایش وزن روزانه از تولد تا سه‌ماهگی (ADGa)، از تولد تا شش‌ماهگی (ADGb) و از سه‌ماهگی تا شش ماهگی (ADGc) و هم‌چنین نسبت های کلیبر منطبق با افزایش وزن های روزانه فوق‌الذکر (KRa، KRb و KRc ) گوسفندان استان گیلان بود. داده‌ها و اطلاعات شجره در طی سال‌های 1373 تا 1390 به وسیله سازمان جهاد کشاورزی استان گیلان جمع‌آوری شده بود. آزمون معنی‌داری اثرات ثابت مؤثر بر صفات مورد مطالعه با استفاده از رویهGLM نرم‌افزار SAS انجام گرفت. اثر ترکیبی گله-‌‌‌ سال-‌ فصل، جنس بره و سن مادر هنگام زایش بر تمامی صفات مورد مطالعه معنی‌دار بودند. پارامترهای ژنتیکی بر اساس 6 مدل حیوانی مختلف و با استفاده از روش حداکثر درستنمایی محدود شده نرم افزارWombat برآورد شدند. مناسب‌ترین مدل بر اساس معیار اطلاعات آکایک تعیین شد. بر اساس بهترین مدل، وراثت‌پذیری مستقیم برای ADGa، ADGb و ADGc و هم‌چنین نسبت های کلیبر منطبق با افزایش وزن های روزانه فوق الذکر به‌ترتیب برابر 79/0، 18/0، 06/0، 25/0، 53/0 و 07/0 بود. همبستگی ژنتیکی مستقیم بین صفات KRb و KRc کم‌ترین (48/0-) و بین صفات ADGc و KRaبیش‌ترین (94/0) مقدار را داشت. همبستگی فنوتیپی در دامنه 37/0- تا 90/0 قرار داشت و همبستگی محیطی نیز از 55/0- تا 90/0 متغیر بود. برآورد پارامتر‌های ژنتیکی صفات رشد در این مطالعه نشان می دهند که در گوسفندان استان گیلان تنوع ژنتیکی کافی و در حد سایر نژادهای گوسفند در ایران وجود دارد و هم‌چنین پیشرفت ژنتیکی برای این صفات به وسیله انتخاب امکان‌پذیر است.

کلیدواژه‌ها


عنوان مقاله [English]

Estimation of Genetic Parameters for Average Daily Gains and Kleiber Ratios in Guilan Province Sheep

نویسندگان [English]

  • Bahareh Eteqadi
  • Navid Ghavi Hossein-Zadeh
  • Abdol Ahad Shadparvar
Department of Animal Science, Faculty of Agricultural Sciences, University of Guilan
چکیده [English]

Introduction: The genetic characterization of local breeds of sheep is of paramount importance, not only for conservation purposes but also for the definition of breeding objectives and breeding programmes. When records are nonexistent and breeds are not well defined in the field, information could be obtained from research station information where pedigree and performance records have been kept. Early growth of animals is mostly dependent on the animal’s genetic merit for growth and maternal genetic and permanent environmental effects. Hence, both the direct and maternal genetic effects should be taken into account in a selection program to achieve optimum genetic progress. Studies on different sheep breeds have indicated that both direct and maternal genetic effects are essential for lamb growth. The efficiency of any sheep production enterprises can be improved through considering economically important traits such as litter size, body weight of lamb and quantity and quality of wool in the breeding objective. Growth is an economically important trait of farm animals which can be interpreted mathematically. It is a time (age) dependent change expressed in the weight or size of organ, composition of tissue/organ, size or number of cells and in live weight. Growth rate is related to rate of maturing and mature weight and these traits have been suggested to have association with lifetime productivity parameters in animals. Slow growth rate causes low market weight and has been identified as one of the limiting factors affecting the profitability of any production system. Selection of animals based on their predicted breeding values and accurate estimation of genetic parameters for economically important traits are required for designing optimal breeding strategies for farm animals. The Kleiber ratio has been suggested to be a useful indicator of growth efficiency and an indirect selection criterion for feed conversion under field conditions. The Guilan sheep is a fat-tailed breed of domestic sheep in Iran, numbering some 400,000 animals in the north of the country, and distributed in the northern and western parts of Guilan Province in the mountains between Assalem, Khalkhal, Oshkourat, and Deilaman. This breed can also be found in some areas of Guilan-Zanjan border. Mean adult live weight in this breed is 35 kg (77 lbs) for rams and 31 kg (67 lbs) for ewes. The coat color for this breed is yellowish-white to pure white, but brown patches are found on the head, face and at the bottom of the legs. This breed is valued mainly due to its small size, meat, and ability to live in mountainous areas with rain-fed foothills and foothill steppes with 1300 mm (51 inches) rain. The objective of the present study was to estimate genetic parameters for average daily gain from birth to 3 (ADGa), 6-month of age (ADGb), average daily gain from 3 to 6-month of age (ADGc) and corresponding Kleiber ratios (KRa، KRb و KRc) in Guilan province sheep.
Materials and Methods: Data and pedigree information used in this study were collected during years 1994 to 2011 by the Agriculture Organization of Guilan Province, Iran. The GLM procedure of SAS was used for determining the fixed effects which had significant influence on the under study traits. Level of significance for the inclusion of effects into the model of analysis was declared at P

کلیدواژه‌ها [English]

  • Fat-tailed sheep
  • Genetic evaluation
  • Growth trait
  • Heritability
1- Abegaz, S., J.B. Van Wyk, and J.J. Olivier. 2005. Model comparisons and genetic and environmental parameter estimates of growth and the Kleiber ratio in Horro sheep. S. Afr. J. Anim. Sci. 35: 30-40.
2- Ahmadi, M., H. Roshanfekr, E. Asadi Khoshoei, and Y. Mohammadi. 2004. Study on genetic and phenotypic parameters for some growth traits in Sanjabi sheep of Kermanshah. J. Agric. Nat. Res. 11(3):91-98. (in Persian with English abstract).
3- Akaike, H. 1974. A new look at the statistical model identification. IEEE Trans. Automat. Contr. 19: 716–723.
4- Asadi Khoshoei, E., S. R. Miraei-Ashtiani, A. Turkmenzehi, Sh. Rahimi, and R. Vaez Torshizi. 2000. Evaluation of Kleiber ratio as one of criterion for selecting ram in Lori Bakhtiari sheep. Iranian J. Agric. Sci. 30(4):649-655. (in Persian with English abstract).
5- Badenhorst, M. A. 1990. The Kleiber ratio as a possible selection for sire selection. The Shepherd. 35: (11): 18-19.
6- Bahreini Behzadi, M. R., F. Eftekhar Shahroudi, and D. Van Vleck. 2005. Effect of maternal traits on heritability estimate and determination of environmental factors affecting on initial growth traits in sheep. J. Sci. Technol. Agric. Nat. Res. 11(1):195-202. (in Persian).
7- Baneh, H.S., and H. Hafezian. 2009. Effects of environmental factors on growth traits in Ghezel sheep. Afr. J. Biotechnol. 8(12): 2903-2907.
8- Bergh, L., M. M. Scholtz, and G. J. Erasmus. 1992. Identification and assessment of the best animals: The Kleiber Ratio as a selection criteria for beef cattle. Proc. Aust. Assoc. Anim. Breed. Genet. 10: 338- 340.
9- Elfadilli, M., C. Michaux, J. Detilleux, and P. L. Leroy. 2000. Genetic parameters for growth traits of the Moroccan Timahdit breed of sheep. Small Rumin. Res. 37: 203-208.
10- Farhangfar, H., H. Naeemipour, and B. Zinvand. 2007. Application of Random Regression Model to Estimate Genetic Parameters for Average Daily Gains in Lori-Bakhtiari Sheep Breed of Iran. Pak. J. Biol. Sci. 10: 2407-2412.
11- Gafouri-Kesbi, F., and M. P. Eskandarinasab. 2008. An evalution of maternal influences on growth traits: the Zandi sheep breed of Iran as an example. J. Anim. Feed Sci. 17: 519-529.
12- Galal, E. S. E., H. R. M. Metawi, A. M. Aboul-Naga, and A. L. Abdel-Aziz. 1996. Performance of and factors affecting the small-holder sheep production system in Egypt. Small Rumin. Res. 19(2): 97-102.
13- Ghafouri-Kesbi, F., M. Ali Abbasi, F. Afraz, M. Babaei, H. Baneh, and R. Abdollahi Arpanahi. 2011. Genetic analysis of growth rate and Kleiber ratio in Zandi sheep. Trop Anim Health Prod. 43(6): 1153-1159.
14- Gholaminia, A. H., and J. Shodja. 2005. Estimation of genetic and phenotypic parameters in Shall sheep. Proceedings of 4th National Conference of Islamic Republic of Iran Biotechnology, Kerman, Iran.
15- Jafaroghli, M., A. Rashidi, M. S. Mokhtari, and A. A. Shadparvar. 2010. (Co)Variance components and genetic parameter estimates for growth traits in Moghani sheep. Small Rumin. Res. 91: 170–177.
16- Kalantar Nistanaki, M. 2004. Study on some environmental factors affecting on growth traits in Zandi sheep. Res. Agric. 4(2):49-58.
17- Karami, K., H. Moradi Shahre Babak, A. Ghazikhani Shad, and A. Mirzamohammadi. 2012. Estimation of genetic parameters for preweaning weight traits in Zandi sheep. Proceedings of 5th Animal Science Congress of Iran, Isfahan, Iran.
18- Matika, O., J. B. Van Wyk, G. J. Erasmus and R. L. Baker, 2003. Genetic parameter estimates in Sabi sheep. Livest. Prod. Sci. 79:17-28.
19- Meyer, K. 2006. WOMBAT- A program for mixed model Analyses by Restricted Maximum Likelihood. User Notes. Animal Genetics and Breeding Unit, Armidale, 55pp.
20- Mohammadi, H., M. Moradi-Shahrebabak, H. Moradi-Shahrebabak, A. Bahrami, and M. Dorostkar. 2013. Model comparisons and genetic parameter estimates of growth and the Kleiber ratio in Shal sheep. Arch. Tierz. 56:264-275.
21- Mohammadi, K., A. Rashidi, M. S. Mokhtari, and M. T. Beigi Nassiri. 2011. The estimation of (co)variance components for growth traits and kleiber ratios in zandi sheep. Small Rumin. Res. 99: 116-121.
22- Mohammadi, Y., A. Rashidi, M. S. Mokhtari, and A. K. Esmailizadeh. 2010. Quantitive genetic analysis of growth traits and kleber ratios in sanjabi sheep. Small Rumin. Res. 93: 88-93.
23- Rafiei, F., N. Emam Jome, and Sh. Nanekarani. 2007. Application of linear models in prediction of animal breeding of animals. 1st ed. Haghshenas publication, Rasht, Iran.
24- Rashidi, A., M. S Mokhtari, A. K. Esmailizadeh, and M. AsadiFozi. 2011. Genetic analysis of ewe productivity traits in Moghani sheep. Small Rumin. Res. 96: 11-15.
25- Rashidi, A., M. S. Mokhtari, A. Safi Jahanshahi, and M. R. Mohammad Abadi. 2008. Genetic parameter estimates of pre-weaning growth traits in Kermani sheep. Small Rumin. Res. 74: 165-171.
26- SAS Institute. 2003. User’s Guide: Statistics, Version 9.1 Edition. SAS Inst., Inc., Cary, NC.
27- Savar-Sofla, S., A. Nejati-Javaremi, and M. Ali Abbasi. 2011. Investigation on direct and maternal effects on growth traits and the Kleiber ratio in Moghani sheep. World Appl. Sci. J. 14 (9): 1313-1319.
28- Schoeman, S. J., 1995. The relevance of W0.75 as predictor of actual weaning efficiency in sheep. Proc. Aust. Assoc. Anim. Breed. Genet. 11: 394-397.
29- Vatankhah, M., M. Moradi Sharebabak, A. Nejati Javarami, S. R. Miraei-Ashtiani, and R. Vaez Torshizi 2004. A review of sheep breeding in Iran. Proc. 1st Iranian Congr. Anim. Aqua. Sci., Tehran, Iran.
30- Willham, R. L. 1972. The role of maternal effects in animal breeding. III. Biometrical aspects of maternal effects in animals. J. Anim. Sci. 35: 1288-1293.