Genetic Parameters of Direct and Maternal Effects for Growth Traits of Afshari Sheep
محورهای موضوعی : Camelآ. خرسند 1 , س.ح. حافظیان 2 , ا. تیموری-یانسری 3 , ا. فرهادی 4
1 - Department of Animal Science, Faculty of Animal Science and Fisheries, Sari Agricultural Science and Natural Resources University, Sari, Iran
2 - Department of Animal Science, Faculty of Animal Science and Fisheries, Sari Agricultural Science and Natural Resources University, Sari, Iran
3 - Department of Animal Science, Faculty of Animal Science and Fisheries, Sari Agricultural Science and Natural Resources University, Sari, Iran
4 - Department of Animal Science, Faculty of Animal Science and Fisheries, Sari Agricultural Science and Natural Resources University, Sari, Iran
کلید واژه: Afshari sheep, genetic parameter, growth traits,
چکیده مقاله :
The genetic parameters and (co) variance components of body weight at birth (BW), weaning (WW) and six months of age (BW6) and average daily gain (ADG) pre and post-weaning of Afshari sheep were estimated using restricted maximum likelihood (REML) methodology and animal model implemented in DFREML software. The likelihood ratio test (LRT) was used to compare the models. Year of birth, age of mother, sex of lamb and type of birth showed significant effects on studied traits, so they were considered as fixed effects in analyzing models. The direct heritability (h2) of BW, WW and BW6 and pre and post-weaning ADG were 0.231, 0.164, 0.246, 0.118 and 0.07, respectively, based on the best model. The maternal effects significantly influenced the pre-weaning traits. The maternal heritability (m2) of BW and the permanent maternal environment effects (c2) of WW and pre-weaning ADG were 0.219, 0.078 and 0.079, respectively. The direct additive genetic (ra) and phenotypic (rp) correlations between studied traits were positive in all cases and ranged from 0.425 to 0.990 and from 0.013 to 0.990, respectively. The maternal permanent environmental correlation (rc) between WW and pre-weaning ADG was 0.984.
پارامترهای ژنتیکی و مولفه‌های (کو) واریانس وزن بدن در تولد (BW)، شیرگیری (WW) و شش ماهگی (BW6) و میانگین افزایش وزن روزانه (ADG) قبل و بعد از شیرگیری گوسفند افشاری با استفاده از روش حداکثر درست‌نمایی محدود شده (REML) و مدل دام در نرم افزار DFREML تخمین زده شدند. تست نسبت درست‌نمایی (LRT) برای مقایسه مدل‌ها مورد استفاده قرار گرفت. سال‌های تولد، سن مادر، جنس بره‌ها و نوع تولد اثرات معنی‌داری را روی صفات مورد مطالعه نشان دادند، بنابراین به عنوان اثرات ثابت در مدل قرار داده شدند. وراثت‌پذیری مستقیم (h2) برای BW، WW و BW6 و ADG قبل و بعد از شیرگیری به ترتیب بر‌اساس بهترین مدل برابر با 231/0، 164/0، 246/0، 118/0 و 07/0 بود. اثرات مادری به طور معنی‌داری صفات قبل از شیرگیری را تحت تأثیر قرار دادند. وراثت‌پذیری مادری (m2) صفت BW و اثرات محیط دائمی مادری (c2) صفات WW و ADG قبل از شیرگیری به ترتیب برابر با 219/0، 078/0 و 079/0 بود. همبستگی‌های مستقیم ژنتیک افزایشی (ra) و فنوتیپی (rp) بین صفات مطالعه شده در همه موارد مثبت بوده و به ترتیب در محدوده‌های 425/0 تا 990/0 و 013/0 تا 990/0 قرار داشتند. همبستگی محیط دائمی مادری (rc) بین WW و ADG قبل از شیرگیری برابر با 984/0 بود.
Abegaz S., Negussie E., Duguma, G. and Rege J.E.O. (2002). Genetic parameter estimates for growth traits in Horro sheep. J. Anim. Breed. Genet. 119, 35-45.
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.
Boujenane I. and Kerfal M. (1990). Estimates of genetic and phenotypic parameters for growth traits of D’man lambs. Anim. Prod. 51, 173-178.
Bradford G.E. (1972). The role of maternal effect in animal breeding :vill maternal effects in sheep. J. Anim. Sci. 35, 1324-1334.
Bromeley C.M., Snowder G.D. and Van Vleck L.D. (2000). Genetic parameters among weight, prolificacy and wool traits of Columbia, Pplypay, Rambouillet and Targhee sheep. J. Anim. Sic. 78, 846-858.
Carolino N., Lopes A.S. and Gama L.T. (2002). Genetic parameters for dairy and growth traits in dual purpose sheep. Pp. 1-4 in Proc. 7th World Cong Gent. Appl. Livest. Prod., Montpellier, France.
Ekiz B. (2004). Estimates of genetic parameters for direct and maternal effect with six different models on birth and weaning weight of Turkish Merino lambs. Turkish J. Vet. Anim. Sci. 28, 383-389.
Ekiz B. (2005). Estimates of maternal effects for pre-and post-weaning daily gain in Turkish Merino lambs. Turkish J. Vet. Anim. Sci. 29, 399-407.
Gilmour A.R., Thompson R. and Cullis B.R. (1995). Average information REML: an efficient algorithm for variance parameter estimation in linear mixed models. Biometrics. 51, 1440-1450.
Gizaw S. and Joshi K. (2004). Estimates of genetic parameters of growth traits in Menz and Awassi × Menz crossbred sheep in Ethiopia. Indian J. Anim. Sci. 74, 864-867.
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.
Hanford K.J., Van Vleck L.D. and Snowder G.D. (2002). Estimates of genetic parameters and genetic change for reproduction, weight and wool characteristics of Columbia sheep. J. Anim. Sci. 80, 3086-3098.
Hanford K.J., Van Vleck L.D. and Snowder G.D. (2003). Estimates of genetic parameters and genetic change for reproduction, weight and wool characteristics of Targhee sheep. J. Anim. Sci. 81, 630-640.
Jurado J.J., Alonso A. and Alenda R. (1994). Selection response for growth in a Spanish merino flock. J. Anim. Sci. 72, 1433-1440.
Kolmosi I. (2008). Genetic parameters for growth traits of the Hungarian merino and meat sheep breeds in Hungary. Appl. Ecol. Environ. Res. 6, 75-82.
Lavvaf A. and Noshary A. (2008). Estimation of genetic parameters and environmental factors on early growth traits for Lori breed sheep using single trait animal model. Pakistan J. Biol. Sci. 11, 74-79.
Maria G.A., Boldman K.G. and Van Vleck L.D. (1993). Estimates of variance due to direct and maternal effects for growth traits of romanov sheep. J. Anim. Sci. 71, 845-849.
Mandal A., Neser F.W.C., Rout P.K., Roy R. and Notter D.R. (2006). Genetic parameters for direct and maternal effects on body weights of Muzaffarnagari sheep. Anim. Sci. 82, 133-140.
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. (2000). DFREML, version 3.1. User notes available: http://agbu.une.edu.au/~kmeyer/df-main.html.
Mokhtari M.S. and Rashidi A. (2010). Genetic trends estimation for body weights of Kermani sheep at different ages using multivariate animal models. Small Rumin. Res. 88, 23-29.
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.
SAS Institute. (2004). SAS®/STAT Software, Release 9. SAS Institute, Inc., Cary, NC.
Safari E., Fogarty N.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.
Snowder G.D. and Van Vleck L.D. (2003). Estimates of genetic parameters and selection strategies to improve the economic efficiency of post-weaning growth in lambs. J. Anim. Sci. 81, 2704-2713.
Snyman M.A., Erusmus G.J., Van Wyke J.B. and Olivier J.J. (1995). Direct and maternal (co) variance component and heritability estimates for body weight at different ages and fleece traits in Afrino sheep. Livest. Prod. Sci. 44, 229-235.
Szwaczkowski T., Wojtowski J., Stanislawska E. and Gut A. (2006). Estimates of maternal genetic and permanent environmental effects in sheep. Arch. Tierz. Dumm. 49, 186-192.
Tosh J.J. and Kemp R.A. (1994). Estimation of variance component for lamb weights in three sheep populations. J. Anim. Sci. 72, 1184-1190.
Yazdi M.H., Engstrom G., Nasholm A., Johnsson K., Jorjani H. and Liljedahi L.E. (1997). Genetic parameters for lamb weight at different ages andwool production in Baluchi sheep. Anim. Sci. 65, 247-255.
