Estimation of genetic parameters and variance components of pre-weaning growth traits in Barki lambs

Sallam, Ahmed M.; Ibrahim, A. H. M.; Alsheikh, S. M.

doi:10.1016/j.smallrumres.2018.11.027

Cited by 30 publications

(20 citation statements)

References 36 publications

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“…Concerning growth characteristics, there are only analyses available which examine the effects of FABP4 and calpastatin on some carcass traits of Barki lambs [29]. Heritabilities of some growth traits in Barki sheep are 0.19, 0.20, and 0.18 for birth weight, weaning weight, and average daily gain, respectively [30]. Therefore, the current study aims to identify segregating polymorphisms of major candidate genes for growth and milk traits in a Barki population of ewes and lambs.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Candidate Genes for Growth and Milk Performance Traits in the Egyptian Barki Sheep

Abousoliman

Reyer

Oster

et al. 2020

Animals

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The most common sheep breeds of Egypt are Ossimi, Rahmani, and Barki breeds. The latter one is well adapted to the challenging desert environment, characterized by food shortage and a high temperature fluctuation. Growth performance of Barki sheep has an important economic value in terms of minimizing the shortage of mutton meat in Egypt. Further, milk production is of great importance for feeding newborn lambs. Eight candidate genes, recently associated with production traits in different breeds, were used to study the effect of genotype on lamb growth and ewe milk traits. The examined genes were LEP, IGF1, DGAT1, STAT5A, PRL, CSN1S2, GHR, and GHRHR, of which one representative single nucleotide polymorphism (SNP) located in the coding region was selected for genotyping. Data from 251 Barki sheep were used in this study. Association analysis between SNPs and lamb growth traits identified rs420693815 of the LEP gene to be significantly associated with weaning weight and average daily gain. In ewes, significant effects on milk yield and composition have been estimated for LEP (rs420693815), STAT5A (rs161082816), PRL (rs422713690), and GHRHR (rs414991449). The results indicated that these genes might be considered as interesting candidates for further investigations to improve growth and milk performance in Barki sheep.

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Section: Introductionmentioning

confidence: 99%

Analysis of Candidate Genes for Growth and Milk Performance Traits in the Egyptian Barki Sheep

Abousoliman

Reyer

Oster

et al. 2020

Animals

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“…Also, Aksoy et al (2016) obtained c 2 ranging from 0.010 to 0.098 for BW and from 0.060 to 0.093 for WW of Karayaka lambs. Moreover, Sallam et al (2019) depicted low c 2 estimates of 0.09, 0.06 and 0.06 for BW, WW and ADG of Barki lambs, respectively. Contradictory, Aguiree et al (2016) reported high c 2 estimates of 0.57, 0.60 and 0.48 for BW, WW and ADG of Santa Ines sheep, respectively.…”

Section: Genetic and Phenotypic Parameters: Variance Components And Hmentioning

confidence: 88%

“…The respective values for Rahmani lambs were 0.191, 0.079 and 0.066 (Table 3). Similarly, several studies on sheep showed that maternal effects represent a crucial portion of variation in early growth traits of lambs (Mostafa et al 2011, Moktari et al 2013, Rashidi 2013, Mohammadi et al 2013, Akthar et al 2014, Jannoune et al 2015, Aguiree et al 2016, Taghi et al, 2016, Baneh and Ahmadpanah 2018, Sallam et al 2019. Therefore, the maternal effects should be considered in the analytical model to achieve more accurate genetic evaluation for early growth traits of lambs.…”

Section: Genetic and Phenotypic Parameters: Variance Components And Hmentioning

confidence: 99%

“…Knowledge of genetic and phenotypic parameters is important for determination of the optimal breeding strategies for the genetic improvement of the lambs' growth traits (Selvaggi et al 2011, Jafari et al 2012, Shokrollahi and Zandieh 2012, Javed et al 2013, Mohammadi et al 2013, Mokhatri et al 2013, Rashidi 2013, Jalil-Sarghale et al 2014, Al-Samarai et al 2015, Aguirre et al 2016, AL-Bial et al 2016, Bayeriyar and Hadi 2016and Jawasreh et al 2018). An accurate prediction of breeding value of growth traits of lambs is an integral part of most genetic improvement breeding programmes (Javed et al 2013, Akthar et al 2014, Roshanfekr 2014, Ahmadpanah et al 2016, Eteqadi et al 2016, Baneh and Ahmadpanah 2018, Yadavet al 2018and Sallam et al 2019. Genetic trends for early growth traits of lambs of different sheep breeds have been indicated by several investigations (Mostafa et al 2011, Hossein-Zadeh 2012, Javed et al 2013, Roshanfekr 2014, Aguirre et al 2016, Ahmadpanah et al 2016, Eteqadi et al 2016, Mallick et al 2016, Baneh and Ahmadpanah 2018, Jawasreh et al 2018, Yadav et al 2018and Sallam et al 2019.…”

Section: Introductionmentioning

confidence: 99%

“…An accurate prediction of breeding value of growth traits of lambs is an integral part of most genetic improvement breeding programmes (Javed et al 2013, Akthar et al 2014, Roshanfekr 2014, Ahmadpanah et al 2016, Eteqadi et al 2016, Baneh and Ahmadpanah 2018, Yadavet al 2018and Sallam et al 2019. Genetic trends for early growth traits of lambs of different sheep breeds have been indicated by several investigations (Mostafa et al 2011, Hossein-Zadeh 2012, Javed et al 2013, Roshanfekr 2014, Aguirre et al 2016, Ahmadpanah et al 2016, Eteqadi et al 2016, Mallick et al 2016, Baneh and Ahmadpanah 2018, Jawasreh et al 2018, Yadav et al 2018and Sallam et al 2019.…”

Section: Introductionmentioning

confidence: 99%

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Genetic Analysis of Pre-Weaning Growth Traits of Barki and Rahmani Lambs

Hammoud

Salem

2019

Egyptian Journal of Animal Production

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Data relevant to 704 Barki and 732 Rahmani lambs born at Alexandria University Experimental Station between 1991-2014 were utilized in this investigation to estimate genetic parameters, breeding values and genetic trends of birth weight (BW), weaning weight (WW) and average daily gain (ADG). The fixed effects of season and year of birth, sex of lamb, type of birth and parity on the considered traits were also studied. The least squares analysis with unequal subclass numbers showed that the overall means of BW, WW and ADG of Barki lambs were 3.69 kg, 20.53 kg and 139.7 g, respectively, the corresponding values for Rahmani lambs were 3.54 kg, 20.09 kg and 137.8 g, respectively. The analysis also indicated that fixed factors effects on all studied traits of both breeds were generally significant (P<0.01or P<0.05) except for the effects of year of birth on BW and parity on WW and ADG of Barki lambs were not significant. Genetic parameters and breeding values for the studied traits were estimated using the Wombat programme fitting Multiveriate Animal Models. Estimates of the direct heritability (h 2 a) were 0.186, 0.078 and 0.073 for BW, WW and ADG of Barki lambs, respectively. The corresponding values for Rahmani lambs were 0.285, 0.130 and 0.121, respectively. Estimates of the maternal heritability (h 2 m) were 0.121, 0.099 and 0.103 for BW, WW and ADG of Barki lambs, respectively. The respective values for Rahmani lambs were 0.097, 0.040 and 0.033, respectively. Estimates of the fraction of variance due to maternal permanent environmental effects (C 2) were 0.024, 0.022 and 0.016 for BW, WW and ADG of Barki lambs, respectively. The corresponding values for Rahmani lambs were 0.094, 0.039 and 0.033, respectively. Maternal effects were considerable portion of variation for early growth traits of both breeds. All correlations were positive and significant (P<0.01). The genetic corrletions were extermely high, being 0.993, 0.991 and 1.000 between BW and WW, between BW and ADG and between WW and ADG of Barki lambs, respectively. The corresponding values for Rahmani lambs were 0.685, 0.677 and 1.000. The maternal genetic correlations were high to extremely high being of 0.775, 0.753 and 0.999 between BW and WW, between BW and ADG and between WW and ADG of Barki lambs, respectively. The respective values for Rahmani lambs were 0.984, 0.988 and 1.000, respectively. The maternal permanent environmental correlations among growth traits of both breeds were extremely high ranged from 0.926 to 0.997. The phenotypic correlations were moderate since they varied from 0.395 to 0.479 between BW and each of WW and ADG of both breeds, and were extremely high being 0.994 and 0.996 between WW and ADG of Barki and Rahmani lambs, respectively. High and positive genetic correlations among lamb's growth traits of both breeds showed that improvement of one trait by selection would cause positive progress in the others. The breeding values for BW, WW and ADG of Barki rams ranged between-0.227 and 0.333 kg, between-1.666 and 2.444 kg and betwe...

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