Comparison of Ordinary and Restricted Selection Indices on Genetic Gain of Body Weight in Iranian Moghani Sheep
الموضوعات :ح. قیاسی 1 , م. خالداری 2 , ر. طاهر خانی 3
1 - Department of Animal Science, Faculty of Agricultural Science, Payame Noor University, Tehran, Iran
2 - Department of Animal Science, Faculty of Agricultural Science, Lorestan University, Khorramabad, Iran
3 - Department of Animal Science, Faculty of Agricultural Science, Lorestan University, Khorramabad, Iran
الکلمات المفتاحية: body weight, Moghani sheep, genetic gain, restricted selection indices,
ملخص المقالة :
The effect of ordinary and restricted selection indices on body weight at different ages changes in birth weight of Iranian Moghani sheep was studied. Traits in the aggregate genotype were birth weight (BW), body weights at 3 (BW3) and 12 months of age (BW12). Two ordinary selection indices (I1 and I2) and two restricted selection indices (R1 and R2) were constructed. BW and BW3 were included in I1 and R1 and BW, BW3 and BW6 were included in I2 and R2. The ranges of expected genetic gains in I1 and I2 for BW, BW3 and BW12 per generation were 0.080 to 0.068, 0.210 to 0.177 and 0.546 to 0.662 kg, respectively. Increasing BW may cause a disorder in the future of breeding goal due to dystocia. Restricted selection indices were constructed to increase BW3 and BW12 while keeping genetic gain in BW to zero. Under selection by indices of R1 and R2 the amount of genetic gain in BW was zero, while considerable genetic gains were obtained for BW3 (0.094 to 0.062) and BW12 (0.39 to 0.60). Ordinary and restricted selection indices were then evaluated in a simulated population. Predicted genetic gains for BW, BW3 and BW12 from ordinary and restricted selection indices were similar to the predicted genetic gains. For both restricted selection indices (R1 and R2) predicted genetic gains for BW3 and BW12 in the simulated population increased over the generations whereas BW decreased slightly over the generations.
Abdollahy H., Hasani S., Zerehdaran S., Shadparvar A. and Mahmoudi B. (2012). Determination of economic values for some important traits in Moghani sheep. Small Rumin. Res. 105, 161-169.
Aziz D. (1988). Restricted selection index for growth traits in sheep [Suffolk and Dorset; modified growth traits]. Dirasat. 15, 162-168.
Cunningham E., Moen R. and Gjedrem T. (1970). Restriction of selection indexes. Biometrics. 26, 67-74.
Dalton D., Knight T. and Johnson D. (1980). Lamb survival in sheep breeds on New Zealand hill country. New Zealand J. Agric. Res. 23, 167-173.
George J. (1976). The incidence of dystocia in Dorset Horn ewes. Australian Vet. J. 52, 519-523.
Haughey K., George J. and McGuirk B. (1985). The repeatability of rearing performance of Merino and Dorset Horn ewes and its relationship with mature pelvic size. Anim. Prod. Sci. 25, 541-549.
Hossein-Zadeh N.G. (2012). Bayesian estimates of genetic changes for body weight traits of Moghani sheep using Gibbs sampling. Trop. Anim. Health Prod. 44, 531-536.
Hossein-Zadeh N.G. and Ardalan M. (2008). Comparison of different models for the estimation of genetic parameters of body weight traits in Moghani sheep. Agric. Food Sci. 19, 207-213.
Jafaroghli M., Rashidi A., Mokhtari M. and Shadparvar A. (2010). (Co)Variance components and genetic parameter estimates for growth traits in Moghani sheep. Small Rumin. Res. 91, 170-177.
Jawasreh K., Al-Barakeh F., Awawdeh F. and Al-Dabbas F. (2006). Restricted selection index for some growth traits of Awassi sheep in Jordan. Pp. 4-17 in Proc. 8th World Cong. Genet. Appl. Livest. Prod. Minas Gerais, Brazil.
Mcsporran K. and Fielden E. (1979). Studies on dystocia in sheep II: Pelvic measurements of ewes with histories of dystocia and eutocia. New Zealand Vet. J. 27, 75-78.
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.
Naderi Y., Vaez T.R., Hafezian S. and Rahimi G.H.A. (2007). Maternal effects on growth traits in Moghani sheep. Iranian J. Agric. Sci. 38, 233-239.
Oramari R. and Hermiz H. (2011). Restricted selection indices for lambs body weights of Karadi sheep in Iraq. Pp. 199-203 in Proc. Int. Cong. Mediterannean Feder. Health Prod. Rumin. Belgrade, Serbia.
Robalo Silva J. and Noakes D. (1984). The effect of experimentally induced hypocalcaemia on uterine activity at parturition in the ewe. Theriogenology. 21, 607-623.
Sawalha R., Conington J., Brotherstone S. and Villanueva B. (2007). Analyses of lamb survival of Scottish Blackface sheep. Animal. 1, 151-157.
Smith G.M. (1977). Factors affecting birth weight, dystocia and preweaning survival in sheep. J. Anim. Sci. 44, 745-753.
Tosh J. and Kemp R. (1994). Estimation of variance components for lamb weights in three sheep populations. J. Anim. Sci. 72, 1184-1190.
Vatankhah M. and Talebi M. (2009). Genetic and non-genetic factors affecting mortality in Lori-Bakhtiari lambs. Asian-Australian J. Anim. Sci. 4, 459-464.
