Salwa El-Wakil - Academia.edu (original) (raw)

Papers by Salwa El-Wakil

Research paper thumbnail of Estimates of Genetic Parameters of Early Growth Traits of Barki Sheep of Egypt

The present study was carried out to estimate genetic parameters for birth weight (BW), weaning w... more The present study was carried out to estimate genetic parameters for birth weight (BW), weaning weight (WW) and average daily gain (ADG) in Barki sheep. The data set used in the present study were records of 1176 lambs, progenies of 83 sires and 690 dams, collected during 1994 to 2001 from the Barki sheep flock raised at Maryout research station, 35 km west of Alexandria, Egypt. The statistical analysis was carried out using restricted maximum likelihood (MTDFREML) methods. Four for model of animal models program including or ignoring maternal genetic and permanent environmental effects were fitted for the studied traits. These models included sex, year of birth and dam's age as fixed effects in addition to animal, sires and dams as random effects. Direct heritability obtained from Model 3, included only maternal additive effects, was estimated at 0.11 for BW, 0.15 for WW and 0.13 for ADG. Maternal heritability estimates for BW, WW and ADG were 0.11, 0.04 and 0.02, respectively....

Research paper thumbnail of Effect of Inbreeding on Some Body Weights in Egyptian Barki Sheep

SUMMARYThe present study utilized the pedigree records of 3191 Barki lamb progenies of 186 sires ... more SUMMARYThe present study utilized the pedigree records of 3191 Barki lamb progenies of 186 sires and 1640 dams reared at two research stations; Ras-Elhekma (from 1963 to 1972) and Maryout (from 1973 to 2004). The current study investigated the effect of inbreeding on body weights at birth, BW, weaning, W120, yearling, W360 and at first mating, W480 in Egyptian Barki sheep flock of the Desert Research Centre. The non-genetic factors affecting the studied traits were investigated. It was found that 4.92% of the present dataset were inbred animals. Average inbreeding coefficient of inbred animals was estimated as 3.57% and appeared to be ranged from 0.05% to 25.20%. Estimate of inbreeding regression coefficient on year of birth for inbred animals were significantly negative in Ras-Elhekma (-0.015) and was not significant in Maryout research station (0.003). Results of pooled data from both stations showed that each one percent increase in inbreeding coefficient resulted in a reduction ...

Research paper thumbnail of Simulation Study on Using Open Nucleus Breeding Scheme for Genetic Improvement of Weaning Weight in Barki Sheep with Special Emphasis on Flock Size

The present article investigated how the expected genetic gain of weaning weight changed in relat... more The present article investigated how the expected genetic gain of weaning weight changed in relation to the size of the nucleus and commercial flocks in order to develop a suitable strategy for improving meat production in Barki sheep. The original body weight data were collected from the Barki sheep flock of the Desert Research Centre from 1963 to 2005 with a total number of 1046 animals (542 females and 504 males) progenies of 163 sires and 557 dams. The simulated sets of data were generated from the original data and designed to construct two scenarios of an open nucleus breeding scheme each consists of a nucleus and 5 contributing commercial flocks. The first scenario concerned with small flock size (1500 ewes and 50 sires in the nucleus flock together with 3000 ewes and 100 sires in each commercial flock), while the second scenario dealt with large flock size (3000 ewes and 100 sires in the nucleus flock in addition to 6000 ewes and 200 sires in each commercial flock). The open...

Research paper thumbnail of Selection index for some body measurements towards improving milk production in Dhofari goat

Research paper thumbnail of The potentiality of milk production and lactation curve in Dhofari goat

Research paper thumbnail of Genetic, phenotypic and environmental trends towards improving body weight in Barki sheep

Research paper thumbnail of Layers of Open Nucleus Breeding Scheme in Relation to the Genetic Improvement of Weaning Weight in Barki Sheep: A Simulation Study

The present study investigated the expected genetic gain of weaning weight by changing the strati... more The present study investigated the expected genetic gain of weaning weight by changing the stratification of the open nucleus breeding scheme from two tires system (ON2) to three tires one (ON3). The original body weight data were collected from the Barki sheep flock of the Desert Research Centre from 1963 to 2005 with a total number of 1046 animals (542 females and 504 males) progenies of 163 sires and 557 dams. The simulated sets of data were generated from the original data and designed to construct ON3 system consisted of a nucleus flock attached with five multiplier flocks and each of them linked to one commercial flock, whereas ON2 system was constructed by simulating a nucleus flock associated with five commercial flocks. The open nucleus breeding scheme was also simulated to allow for the exchange of superior sires among tires in both directions. Three generations of progenies were obtained by selection of sires and dams for the next generations. The annual genetic gain as a...

Research paper thumbnail of Selection Index for Wool Improvement in Barki Sheep

The present study was carried out to estimate genetic and phenotypic parameters for some subjecti... more The present study was carried out to estimate genetic and phenotypic parameters for some subjective and objective wool traits to develop a suitable selection index for wool improvement in Barki sheep. Over 937 fleeces were obtained from three Barki sheep flocks along the north western coastal belt of Egypt together with full pedigree information for those 937 animals descended from 74 sires and 896 ewes. After the first shearing, a composite wool sample was collected to represent the entire fleece of each animal. The greasy wool samples were subjectively assessed for kemp score, KS, greasy colour grade, GCG, handle grade, HG, lustre grade, LG, bulk grade, BLG and measured for staple length, STL. After scouring, the scoured colour grade, SCG was also assessed. SAS and MTDFREML statistical programs were used to generate analysis of variance and estimating genetic and phenotypic parameters as well as constructing selection indexes. Results indicated that Barki wool had higher than aver...

Research paper thumbnail of Genetic and Phenotypic Parameters of Birth, Weaning and Yearling Body Weights of Barki Sheep Raised in the North Western Coast of Egypt

SUMMARY The present study investigated environmental factors affecting birth (BW), weaning (WW) a... more SUMMARY The present study investigated environmental factors affecting birth (BW), weaning (WW) and yearling body weights (YW) and estimated the heritabilities and genetic correlations of these traits in a Barki sheep flock maintained in the north western coast of Egypt. Body weight data of 1046 animals (542 females and 504 males) progenies of 163 sires and 557 dams obtained from 1963 to 2005 were used. Data were analyzed using a model composed of location, year of birth within location, sex of lamb and age of dam. Moreover, heritabilities as well as genetic and phenotypic correlations were estimated using multiple traits animal model. Barki males had significantly heavier body weights than females at birth (3.64 kg vs 3.46 kg), weaning (19.56 kg vs 18.44 kg) and at 12-month of age (32.05 kg and 30.02 kg). Year of birth within location showed highly significant effects on the studied body weights. Furthermore, age of dam revealed highly significant effect on birth weight, where olde...

Research paper thumbnail of Relationships Among Some Growth Performance Traits and Lifetime Productivity of Barki Ewes

Journal of Animal and Poultry Production

The present study was conducted to characterize lifetime performance of Barki ewes, estimating so... more The present study was conducted to characterize lifetime performance of Barki ewes, estimating some genetic and phenotypic parameters for total lifetime performance traits and investigate the possibility of improving these traits. Lifetime performance records for 1040 Barki ewes daughters of 194 sires and 729 dams were obtained from 1963 to 2010 from the sheep flock of the Desert Research Centre and used in the present study. Data was analyzed using SAS and MTDFREML programs to carry out analysis of variance and estimate genetic and phenotypic parameters for the studied traits. The current study dealt with lifespan, productive, reproductive and partial lifetime productive traits. Lifespan traits included total lifetime, TLT, productive life, PL and lifetime score. Lifetime productive traits included total number and weight of lambs born and weaned. Lifetime reproductive traits included age at first lambing, AgFL, and lambing interval, LI. Three partial life time productive traits were calculated i.e., after the first lambing, cumulative first two lambing, and cumulative three lambing. Results showed that throughout the lifetime, Barki ewe on the average gave birth to 2.77 lambs weighing 9.74 kg at birth and able to rear 2.53 weaned lambs weighing 49.01 kg at weaning. Barki ewes showed an average TLT of 2301.63 days (i.e., 6.3 years), during which she has 2.71 lambing season. PL represented 37.8% of TLT of the ewe while AgFL, accounted for 39% of TLT. Average LI, was 344.44 days. The present study emphasized on improving reproductive efficiency of Barki ewes in this flock rather than removing non-lambing ewes. Birth year had highly significant effect on all studied traits. Heritabilities were estimated for lifetime productive traits (ranged from 0.24 to 0.31), lifespan traits (ranged from 0.07 to 0.16) and lifetime reproductive traits (ranged from 0.03 to 0.12). Highly significant and positive genetic and phenotypic correlations were obtained between lifetime productive traits and lifespan traits. The partial trait of weight of lambs weaned for the first three lambing was found to be moderately heritable and highly significant positively associated genetically and phenotypically with the total weight of lamb weaned (TWLW) which recommend the utility of this trait as an indirect selection criterion to improve the TWLW throughout the lifetime. Selection based on total weight of lambs weaned after the first lambing is likely to achieve the target at an earlier stage.

Research paper thumbnail of Evaluation of Direct and Maternal ( CO ) Variance Components and Heritabilities for Some Body Weights and Growth Traits in Barki Sheep

Egyptian Journal of Sheep and Goat Sciences

Research paper thumbnail of Genetic Improvement of Weaning Weight in Barki Sheep Using Nucleus Breeding Scheme

Egyptian Journal of Sheep and Goat Sciences, 2014

Research paper thumbnail of Estimates of (Co) Variance Components for Direct and Maternal Effects on Birth Weight of Egyptian Barki Lambs

Journal of Animal and Poultry Production

The present study was undertaken to estimate (co) variance components for birth weight (BW) of Ba... more The present study was undertaken to estimate (co) variance components for birth weight (BW) of Barki lamb's. The models fitted included direct genetic, maternal genetic and direct-maternal genetic co-variance and maternal permanent environmental effects using six forms of animal models (MTDFREML). Data and pedigree information of the studied Barki sheep were collected from 1994 to 2001. A direct heritability estimate of 0.12 and maternal heritability estimate of 0.21 were obtained for BW. Maternal permanent environmental effect was found to be 0.092 with little contribution on BW. The estimate of the direct-maternal correlation was high and positive. Results indicated that the inclusion of maternal effects in genetic evaluation of early growth traits in Barki lambs were significant and need to be considered in any selection program to improve Barki sheep.

Research paper thumbnail of Estimates of Genetic Parameters of Early Growth Traits of Barki Sheep of Egypt

The present study was carried out to estimate genetic parameters for birth weight (BW), weaning w... more The present study was carried out to estimate genetic parameters for birth weight (BW), weaning weight (WW) and average daily gain (ADG) in Barki sheep. The data set used in the present study were records of 1176 lambs, progenies of 83 sires and 690 dams, collected during 1994 to 2001 from the Barki sheep flock raised at Maryout research station, 35 km west of Alexandria, Egypt. The statistical analysis was carried out using restricted maximum likelihood (MTDFREML) methods. Four for model of animal models program including or ignoring maternal genetic and permanent environmental effects were fitted for the studied traits. These models included sex, year of birth and dam's age as fixed effects in addition to animal, sires and dams as random effects. Direct heritability obtained from Model 3, included only maternal additive effects, was estimated at 0.11 for BW, 0.15 for WW and 0.13 for ADG. Maternal heritability estimates for BW, WW and ADG were 0.11, 0.04 and 0.02, respectively....

Research paper thumbnail of Effect of Inbreeding on Some Body Weights in Egyptian Barki Sheep

SUMMARYThe present study utilized the pedigree records of 3191 Barki lamb progenies of 186 sires ... more SUMMARYThe present study utilized the pedigree records of 3191 Barki lamb progenies of 186 sires and 1640 dams reared at two research stations; Ras-Elhekma (from 1963 to 1972) and Maryout (from 1973 to 2004). The current study investigated the effect of inbreeding on body weights at birth, BW, weaning, W120, yearling, W360 and at first mating, W480 in Egyptian Barki sheep flock of the Desert Research Centre. The non-genetic factors affecting the studied traits were investigated. It was found that 4.92% of the present dataset were inbred animals. Average inbreeding coefficient of inbred animals was estimated as 3.57% and appeared to be ranged from 0.05% to 25.20%. Estimate of inbreeding regression coefficient on year of birth for inbred animals were significantly negative in Ras-Elhekma (-0.015) and was not significant in Maryout research station (0.003). Results of pooled data from both stations showed that each one percent increase in inbreeding coefficient resulted in a reduction ...

Research paper thumbnail of Simulation Study on Using Open Nucleus Breeding Scheme for Genetic Improvement of Weaning Weight in Barki Sheep with Special Emphasis on Flock Size

The present article investigated how the expected genetic gain of weaning weight changed in relat... more The present article investigated how the expected genetic gain of weaning weight changed in relation to the size of the nucleus and commercial flocks in order to develop a suitable strategy for improving meat production in Barki sheep. The original body weight data were collected from the Barki sheep flock of the Desert Research Centre from 1963 to 2005 with a total number of 1046 animals (542 females and 504 males) progenies of 163 sires and 557 dams. The simulated sets of data were generated from the original data and designed to construct two scenarios of an open nucleus breeding scheme each consists of a nucleus and 5 contributing commercial flocks. The first scenario concerned with small flock size (1500 ewes and 50 sires in the nucleus flock together with 3000 ewes and 100 sires in each commercial flock), while the second scenario dealt with large flock size (3000 ewes and 100 sires in the nucleus flock in addition to 6000 ewes and 200 sires in each commercial flock). The open...

Research paper thumbnail of Selection index for some body measurements towards improving milk production in Dhofari goat

Research paper thumbnail of The potentiality of milk production and lactation curve in Dhofari goat

Research paper thumbnail of Genetic, phenotypic and environmental trends towards improving body weight in Barki sheep

Research paper thumbnail of Layers of Open Nucleus Breeding Scheme in Relation to the Genetic Improvement of Weaning Weight in Barki Sheep: A Simulation Study

The present study investigated the expected genetic gain of weaning weight by changing the strati... more The present study investigated the expected genetic gain of weaning weight by changing the stratification of the open nucleus breeding scheme from two tires system (ON2) to three tires one (ON3). The original body weight data were collected from the Barki sheep flock of the Desert Research Centre from 1963 to 2005 with a total number of 1046 animals (542 females and 504 males) progenies of 163 sires and 557 dams. The simulated sets of data were generated from the original data and designed to construct ON3 system consisted of a nucleus flock attached with five multiplier flocks and each of them linked to one commercial flock, whereas ON2 system was constructed by simulating a nucleus flock associated with five commercial flocks. The open nucleus breeding scheme was also simulated to allow for the exchange of superior sires among tires in both directions. Three generations of progenies were obtained by selection of sires and dams for the next generations. The annual genetic gain as a...

Research paper thumbnail of Selection Index for Wool Improvement in Barki Sheep

The present study was carried out to estimate genetic and phenotypic parameters for some subjecti... more The present study was carried out to estimate genetic and phenotypic parameters for some subjective and objective wool traits to develop a suitable selection index for wool improvement in Barki sheep. Over 937 fleeces were obtained from three Barki sheep flocks along the north western coastal belt of Egypt together with full pedigree information for those 937 animals descended from 74 sires and 896 ewes. After the first shearing, a composite wool sample was collected to represent the entire fleece of each animal. The greasy wool samples were subjectively assessed for kemp score, KS, greasy colour grade, GCG, handle grade, HG, lustre grade, LG, bulk grade, BLG and measured for staple length, STL. After scouring, the scoured colour grade, SCG was also assessed. SAS and MTDFREML statistical programs were used to generate analysis of variance and estimating genetic and phenotypic parameters as well as constructing selection indexes. Results indicated that Barki wool had higher than aver...

Research paper thumbnail of Genetic and Phenotypic Parameters of Birth, Weaning and Yearling Body Weights of Barki Sheep Raised in the North Western Coast of Egypt

SUMMARY The present study investigated environmental factors affecting birth (BW), weaning (WW) a... more SUMMARY The present study investigated environmental factors affecting birth (BW), weaning (WW) and yearling body weights (YW) and estimated the heritabilities and genetic correlations of these traits in a Barki sheep flock maintained in the north western coast of Egypt. Body weight data of 1046 animals (542 females and 504 males) progenies of 163 sires and 557 dams obtained from 1963 to 2005 were used. Data were analyzed using a model composed of location, year of birth within location, sex of lamb and age of dam. Moreover, heritabilities as well as genetic and phenotypic correlations were estimated using multiple traits animal model. Barki males had significantly heavier body weights than females at birth (3.64 kg vs 3.46 kg), weaning (19.56 kg vs 18.44 kg) and at 12-month of age (32.05 kg and 30.02 kg). Year of birth within location showed highly significant effects on the studied body weights. Furthermore, age of dam revealed highly significant effect on birth weight, where olde...

Research paper thumbnail of Relationships Among Some Growth Performance Traits and Lifetime Productivity of Barki Ewes

Journal of Animal and Poultry Production

The present study was conducted to characterize lifetime performance of Barki ewes, estimating so... more The present study was conducted to characterize lifetime performance of Barki ewes, estimating some genetic and phenotypic parameters for total lifetime performance traits and investigate the possibility of improving these traits. Lifetime performance records for 1040 Barki ewes daughters of 194 sires and 729 dams were obtained from 1963 to 2010 from the sheep flock of the Desert Research Centre and used in the present study. Data was analyzed using SAS and MTDFREML programs to carry out analysis of variance and estimate genetic and phenotypic parameters for the studied traits. The current study dealt with lifespan, productive, reproductive and partial lifetime productive traits. Lifespan traits included total lifetime, TLT, productive life, PL and lifetime score. Lifetime productive traits included total number and weight of lambs born and weaned. Lifetime reproductive traits included age at first lambing, AgFL, and lambing interval, LI. Three partial life time productive traits were calculated i.e., after the first lambing, cumulative first two lambing, and cumulative three lambing. Results showed that throughout the lifetime, Barki ewe on the average gave birth to 2.77 lambs weighing 9.74 kg at birth and able to rear 2.53 weaned lambs weighing 49.01 kg at weaning. Barki ewes showed an average TLT of 2301.63 days (i.e., 6.3 years), during which she has 2.71 lambing season. PL represented 37.8% of TLT of the ewe while AgFL, accounted for 39% of TLT. Average LI, was 344.44 days. The present study emphasized on improving reproductive efficiency of Barki ewes in this flock rather than removing non-lambing ewes. Birth year had highly significant effect on all studied traits. Heritabilities were estimated for lifetime productive traits (ranged from 0.24 to 0.31), lifespan traits (ranged from 0.07 to 0.16) and lifetime reproductive traits (ranged from 0.03 to 0.12). Highly significant and positive genetic and phenotypic correlations were obtained between lifetime productive traits and lifespan traits. The partial trait of weight of lambs weaned for the first three lambing was found to be moderately heritable and highly significant positively associated genetically and phenotypically with the total weight of lamb weaned (TWLW) which recommend the utility of this trait as an indirect selection criterion to improve the TWLW throughout the lifetime. Selection based on total weight of lambs weaned after the first lambing is likely to achieve the target at an earlier stage.

Research paper thumbnail of Evaluation of Direct and Maternal ( CO ) Variance Components and Heritabilities for Some Body Weights and Growth Traits in Barki Sheep

Egyptian Journal of Sheep and Goat Sciences

Research paper thumbnail of Genetic Improvement of Weaning Weight in Barki Sheep Using Nucleus Breeding Scheme

Egyptian Journal of Sheep and Goat Sciences, 2014

Research paper thumbnail of Estimates of (Co) Variance Components for Direct and Maternal Effects on Birth Weight of Egyptian Barki Lambs

Journal of Animal and Poultry Production

The present study was undertaken to estimate (co) variance components for birth weight (BW) of Ba... more The present study was undertaken to estimate (co) variance components for birth weight (BW) of Barki lamb's. The models fitted included direct genetic, maternal genetic and direct-maternal genetic co-variance and maternal permanent environmental effects using six forms of animal models (MTDFREML). Data and pedigree information of the studied Barki sheep were collected from 1994 to 2001. A direct heritability estimate of 0.12 and maternal heritability estimate of 0.21 were obtained for BW. Maternal permanent environmental effect was found to be 0.092 with little contribution on BW. The estimate of the direct-maternal correlation was high and positive. Results indicated that the inclusion of maternal effects in genetic evaluation of early growth traits in Barki lambs were significant and need to be considered in any selection program to improve Barki sheep.