Estimating Genetic Parameters of Body Weight Traits in Kourdi Sheep

محورهای موضوعی : Camel

ع.ر. شهدادی ¹ ( Department of Animal Science, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran )
د.ع. ساقی ² ( Department of Animal Science, Agricultural and Natural Resources Research and Education Center of Khorasan Razavi, Mashhad, Iran )

تاریخ دریافت : 1394/06/07 تاریخ پذیرش : 1395/07/10 تاریخ انتشار : 1395/06/11

کلید واژه: body weight, heritability, Kourdi sheep, variance component,

چکیده مقاله :

For estimating genetic parameters for body weight traits in Kourdi sheep data were collected from 1996 to 2013 in Kourdi Breeding Station in Northern Khorasan province of Iran. Studied traits were birth weight (BW), weaning weight (WW), six-month weight (6MW), nine-month weight (9MW) and yearling weight (YW). The fixed effects in the model were lambing year, sex, type of birth and age of dam. (Co)variance components and corresponding genetic parameters were obtained with the univariate and multivariate analyses fitting animal models using the restricted maximum likelihood (REML) methods. The most appropriate model for each trait was determined based on log likelihood values. Model including maternal genetic effects as well as direct genetic effects, without considering covariance between them, was chosen as the most appropriate model for BW and WW. Model which included only direct genetic effects was the best model for other traits (6MW, 9MW and YW). Year of birth, lamb sex and type of birth were significant sources of variation on body weight traits (P<0.01). Direct heritability estimates of 0.10, 0.28, 0.32, 0.22 and 0.20 were obtained for BW, WW, 6MW, 9MW and YW, respectively. The estimate of maternal heritabilities for BW and WW were 0.27 and 0.13, respectively. Direct genetic correlation estimates between body weight traits were positive ‎and varied from 0.56 for BW-YW to 0.97 for 6MW-9MW. Estimates of maternal genetic correlations between body ‎weight traits were positive and ranged from 0.84 to 0.99. The estimates of correlations between body weight traits suggest that selection for any of these traits could result in genetic progress for the other traits.‎

چکیده انگلیسی:

برای برآورد پارامترهای ژنتیکی صفات وزن بدن در گوسفند کردی داده­های جمع­آوری شده طی سال­های 1375 تا 1392 در ایستگاه پرورش و اصلاح نژاد گوسفند کردی واقع در شهرستان شیروان استان خراسان شمالی مورد استفاده قرار گرفت. صفات مورد مطالعه شامل وزن تولد (BW)، وزن 3 ماهگی (WW)، وزن 6 ماهگی (6MW)، وزن 9 ماهگی (9MW) و وزن یک سالگی (YW) بود. اثرات ثابت موجود در مدل سال زایش، جنس بره، نوع تولد و سن مادر هنگام زایش بود. مؤلفه­های (کو)واریانس و پارامترهای ژنتیکی صفات با تجزیه و تحلیل­های یک و چند متغیره مدل­های حیوانی با استفاده از روش حداکثر درست­نمایی محدود شده برآورد گردید. پس از برازش مدل­های حیوانی مورد استفاده، مناسب­ترین مدل برای هر صفت بر اساس مقادیر لگاریتم حداکثر درست­نمایی انتخاب شد. مدل حاوی اثرات ژنتیکی افزایشی مستقیم و اثرات ژنتیکی مادری بدون در نظر گرفتن کوواریانس بین آنها مناسب­ترین مدل برای صفات BW و WW بود. مدل حاوی اثرات ژنتیکی افزایشی به عنوان بهترین مدل برای سایر صفات (6MW، 9MW و YW) در نظر گرفته شد. سال زایش، جنس بره و نوع تولد تأثیر معنی­داری روی صفات وزن بدن داشتند (01/0>P). وراثت­پذیری برآورد شده برای صفات BW، WW، 6MW، 9MW و YW به ترتیب 10/0، 28/0، 32/0، 22/0 و 20/0 بود. وراثت­پذیری مادری برای BW و WW به ترتیب 27/0 و 13/0 برآورد گردید. همبستگی­های ژنتیکی افزایشی مستقیم بین صفات مختلف وزن بدن به ترتیب در دامنه 56/0 (BW با YW) تا 97/0 (6MW با 9MW) متغیر بود. همبستگی­های ژنتیکی افزایشی مادری بین صفات وزن بدن در محدوده 84/0 تا 99/0 قرار داشت. همبستگی­های برآورد شده بین صفات نشان می­دهد که انتخاب برای هر کدام از این صفات باعث بهبود پیشرفت ژنتیکی در سایر صفات می­شود.

منابع و مأخذ:

Abegaz S., Van Wyk J.B. and Olivier J.J. (2005). Model comparisons and genetic and environmental parameter estimates of growth and the Kleiber ratio in Horro sheep. South African J. Anim. Sci. 35, 30-40.

Al-ShorepyS.A. (2001). Estimates of genetic parameters for direct and maternal effects on birth weight of local sheep in United Arab Emirates. Small Rumin. Res. 39, 219-224.

Bahreini Behzadi M.R., Shahroudi F.E. and Van Vleck L.D. (2007). Estimates of genetic parameters for growth traits in Kermani sheep. J. Anim. Breed. Genet. 124, 296-301.

Dixit S.P., Dhilon J.S. and Sing D. (2001). Genetic and nongenetic parameter estimates for growth traits of Bharat Merino lambs. Small Rumin. Res. 42, 101-104.

Duguma G., Schoeman S.J., Cloete S.W.P. and Jordan G.F. (2002). Genetic parameter estimates of early growth traits in the Tygerhoek Merino flock. South African J. Anim. Sci. 32, 66-75.

Eskandarinasab M., Ghafouri-Kesbi F. and Abbasi M.A. (2010). Different models for evaluation of growth traits and Kleiber ratio in an experimental flock of Iranian fat-tailed Afshari sheep. J. Anim. Breed. Genet. 127, 26-33.

Gizaw S., Lemma S., Komen H. and Van Arendonk J.A.M. (2007). Estimates of genetic parameters and genetic trends for live weight and fleece traits in Menz sheep. Small Rumin. Res. 70, 145-153.

Maniatis N. and Pollott G.E. (2003). The impact of data structure on genetic (co)variance components of early growth in sheep, estimated using an animal model with maternal effects. J. Anim. Sci. 81, 101-108.

Maria G.A., Boldman K.G. and Van Vleck L.D. (1993). Estimates of variances due to direct and maternal effects for growth traits of Romanov sheep. J. Anim. Sci. 71, 845-849.

Matika O., Van Wyk J.B., Erasmus G.J. and Baker R.L. (2003). Genetic parameter estimates in Sabi sheep. Livest. Prod. Sci. 79, 17-28.

Meyer K. (1992). Variance components due to direct and maternal effects for growth traits of Australian beef cattle. Livest. Prod. Sci. 31, 179-204.

‎Meyer K. (2012). WOMBAT, A program for Mixed Model Analyses by Restricted ‎Maximum Likelihood. User Notes. Animal Genetics and Breeding Unit, University of New ‎England Armidale, Australia.‎

Miraei-Ashtiani S.R., Seyedalian S.A.R. and Moradi Shahrbabak M. (2007). Variance components and heritabilities for body weight traits in Sangsari sheep, using univariate and multivariate animal models. Small Rumin. Res. 73, 109-114.

Mohammadi Y., Rashidi A., Mokhtari M.S. and Esmailizadeh A.K. (2010). Quantitative genetic analysis ‎of growth traits and kleiber ratios in Sanjabi sheep. Small Rumin. Res. 93, 88-93.‎

Mokhtari M.S., Rashidi A. and Mohammadi Y. (2008). Estimation of genetic parameters for post-weaning traits of Kermani sheep. Small Rumin. Res. 80, 22-27.

Mousa E., Van Vleck L.D. and Leymaster K.A. (1999). Genetic parameters for growth traits for a composite terminal sire breed of sheep. J. Anim. Sci. 77, 1659-1665.

Neser F.W.C., Erasmus G.J. and Van Wyk J.B. (2001). Genetic parameter estimates for pre-weaning weight traits in Dorper sheep. Small Rumin. Res. 40, 197-202.

‎Rashidi A., Mokhtari M.S., Safi Jahanshahi A. and Mohammad Abadi ‏‎M.R. (2008). Genetic ‎parameter estimates of pre-weaning growth traits in‏ ‏Kermani sheep. Small Rumin. Res. 74, 165-‎‎171.‎

Robison O.W. (1981). The influence of maternal effects on the efficiency of selection: a review. Livest. Prod. Sci. 8, 121-137.

Safari E., FogartyN.M. and Gilmour A.R. (2005). A review of genetic parameter estimates for wool, growth, meat and reproduction traits in sheep. Livest. Prod. Sci. 92, 271-289.

‎Saghi D.A., Yavari A., Mobaraki A., Davtalab A., Khoshghamat S., Mohammad zadeh M., Bozorgmahr M., Ashkanifar R., Hend Abadi M. and Robati M. (2014). Statistics and Data of Kurdish Sheep ‎Breeding Station. Arshadan Press, Tehran, Iran.

SAS Institute. (2008). SAS^®/STAT Software, Release 9.2. SAS Institute, Inc., Cary, NC. USA.

Shojaei M., Mohammad Abadi M.R., Asadi Fozi M., Dayani O., Khezri A. and Akhondi M. (2011). Association of growth trait and Leptin gene polymorphism in Kermani sheep. J. Cell Mol. Res. 2, 67-73.

Snyman M.A., Erasmus G.J., Van Wyk J.B. and Olivier J.J. (1995). Direct and maternal (co)variance components and heritability estimates for body weight at different ages and fleece traits in Afrino sheep. Livest. Prod. Sci. 44, 229-235.

Tavakolian J. (1999). The Genetic Resources of Native Farm Animals of Iran. Animal Science Research Institute of Iran. Sepidrood Press, Tehran, Iran.

Van Wyk J.B., Erasmus G.J. and Konstantinov K.V. (1993). Variance component and heritability estimates of early growth traits in the Elsenburg Dormer sheep stud. South African J. Anim. Sci. 23, 72-76.

Vatankhah M. and Talebi M.A. (2008). Heritability estimates and correlations between production and reproductive traits in Lori-Bakhtiari sheep in Iran. South African J. Anim. Sci. 38, 110-118.

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.

Yazdi M.H., Engstrom G., Nasholm A., Johansson K., Jorjani H. and Liljedahl L.E. (1997). Genetic parameters for lamb weight at different ages and wool production in Baluchi sheep. J. Anim. Sci. 65, 247-255.

Zamani P., Akhondi M., Mohammadabadi M.R., Saki A.A., Ershadi A., Banabazi M.H. and Abdolmohammadi A.R. (2013). Genetic variation of Mehraban sheep using two inter-simple sequence repeat (ISSR) markers. South African Biotechnol. 10, 1812-1817.

Zamani P., Akhondi M. and Mohammadabadi M.R. (2015). Associations of inter-simple sequence repeat loci with predicted breeding values of body weight in Sheep. Small Rumin. Res. 132, 123-127.