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  1. Article ; Online: Multivariate Animal Model-based Analysis of Fiber Traits in Kashmir Merino Sheep

    Ahmad, Sheikh Firdous / Rather, Mubashir Ali / Shanaz, Syed / Khan, Nusrat Nabi / Ganai, Nazir Ahmad

    Journal of Natural Fibers. 2022 Oct. 28, v. 19, no. 14 p.7948-7955

    2022  

    Abstract: An attempt was made in the present study to elucidate the (co)variance components and genetic parameters of fiber traits in Kashmir Merino sheep population using multivariate animal model. The data pertained to a total of 6836 sheep lambs born over a ... ...

    Abstract An attempt was made in the present study to elucidate the (co)variance components and genetic parameters of fiber traits in Kashmir Merino sheep population using multivariate animal model. The data pertained to a total of 6836 sheep lambs born over a period of 21 years (1997–2017) and included information on different fiber traits [greasy fleece weight at first (GFW1) and second (GFW2) clips; and fiber diameter (FD) and staple length (SL) at second clip]. Genetic analysis was undertaken using average information restricted maximum likelihood (AI-REML) algorithm in WOMBAT program. The model incorporated six fixed (sex of lamb, season and period of birth, farm of origin, breed and type of birth) and two random effects (direct additive genetic and maternal genetic effects without any covariance between them) in it. The additive genetic heritability estimates for fiber traits were 0.300 ± 0.031; 0.289 ± 0.022; 0.254 ± 0.029 and 0.189 ± 0.028 for GFW1, GFW2, FD, and SL, respectively. The maternal genetic heritability estimates were very low for all traits under study. The genetic correlation between different traits was positive and estimates ranged from moderate to high. The results from present study imply that the variation in these traits has genetic basis which can be exploited in the selection programmes for their improvement. The correlation between different fiber traits was found to be favorable, which can lead to indirect selection response upon formulation of efficient breeding programmes.
    Keywords Merino ; algorithms ; animal models ; covariance ; farms ; fleece ; genetic analysis ; genetic correlation ; heritability ; selection response ; sheep ; staple (fibers) ; variance ; India ; Correlation ; maternal ; model ; trait
    Language English
    Dates of publication 2022-1028
    Size p. 7948-7955.
    Publishing place Taylor & Francis
    Document type Article ; Online
    ZDB-ID 2182715-1
    ISSN 1544-046X ; 1544-0478
    ISSN (online) 1544-046X
    ISSN 1544-0478
    DOI 10.1080/15440478.2021.1958425
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    Z 7564: Show issues

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  2. Article ; Online: Comparison of various models for the estimation of heritability and breeding values.

    Hamadani, Ambreen / Ganai, Nazir A / Khan, Nusrat Nabi / Shanaz, Syed / Rather, Mubashir Ali / Ahmad, Haider A / Shah, Ruksana

    Tropical animal health and production

    2023  Volume 55, Issue 4, Page(s) 250

    Abstract: The exploration of additive genetic variance for the selection of animals is the central paradigm in quantitative genetics and it is important to use appropriate animal models considering important factors. This study compares various factor effects for ... ...

    Abstract The exploration of additive genetic variance for the selection of animals is the central paradigm in quantitative genetics and it is important to use appropriate animal models considering important factors. This study compares various factor effects for heritability and breeding values estimations on data collected on the Corriedale. Overall, the heritability estimates were the highest for birthweight (BW). Both the additive genetic variance and the heritability values were reduced upon adding more random effects. Year-effect as random reduced the heritability except for BW. The highest average accuracy for breeding values for birth, weaning, 6, 9, and 12-month-weights for were 0.656, 0.567, 0.519, 0.486, and 0.515. These were observed for models having sex or sex and parity as fixed effects. It is concluded that fixed and random factors have a significant impact on genetic-factors and breeding-value accuracies and should be considered during selection programs and make the selection program more effective.
    MeSH term(s) Pregnancy ; Female ; Animals ; Birth Weight/genetics ; Parity ; Parturition ; Weaning ; Models, Animal ; Models, Genetic ; Phenotype ; Body Weight/genetics
    Language English
    Publishing date 2023-06-24
    Publishing country United States
    Document type Journal Article
    ZDB-ID 603363-5
    ISSN 1573-7438 ; 0049-4747
    ISSN (online) 1573-7438
    ISSN 0049-4747
    DOI 10.1007/s11250-023-03665-6
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  3. Article ; Online: Multivariate quantitative genetic analysis of body weight traits in Corriedale sheep.

    Ahmad, Sheikh Firdous / Khan, Nusrat Nabi / Ganai, Nazir Ahmad / Shanaz, Syed / Rather, Mubashir Ali / Alam, Safeer

    Tropical animal health and production

    2021  Volume 53, Issue 2, Page(s) 197

    Abstract: In the present study, an attempt was made to elucidate the genetic parameters for body weight traits of lambs from Corriedale sheep population at different ages. Data were collected from 6874 lambs born over a span of 49 years from 1969 to 2017. The ... ...

    Abstract In the present study, an attempt was made to elucidate the genetic parameters for body weight traits of lambs from Corriedale sheep population at different ages. Data were collected from 6874 lambs born over a span of 49 years from 1969 to 2017. The traits under study included body weight at birth (BW), weaning (WW), 6 months of age (6MW), 9 months of age (9MW) and yearling stage (YW). Data were statistically analyzed using restricted maximum likelihood (REML) algorithm in WOMBAT program. A multi-variate animal model was fitted to the data incorporating season and period of lambing, sex of lamb and litter size as fixed effects. Variance and covariance components were estimated using the animal model after incorporating direct additive genetic effect of animal as random factor. Genetic and phenotypic correlations with corresponding standard errors were also estimated. The heritability estimates for BW, WW, 6MW, 9MW and YW were 0.130 ± 0.023, 0.300 ± 0.029, 0.292 ± 0.030, 0.191 ± 0.025 and 0.169 ± 0.024, respectively. The genetic correlation between different traits under study was high, except between BW and 9MW for which the estimate was moderate. Phenotypic correlation ranged from low to high for different trait combinations. Among different traits under study, only two traits showed moderate heritability i.e. WW and 6MW while heritability of other traits was low. Both these traits showed high correlation with all subsequent traits. Selection programme for Corriedale sheep should be based on WW which is expressed early in life and shall lead to moderate genetic response to selection.
    MeSH term(s) Animals ; Birth Weight/genetics ; Body Weight/genetics ; Female ; Litter Size ; Male ; Models, Genetic ; Multivariate Analysis ; Phenotype ; Seasons ; Sheep, Domestic/genetics ; Weaning
    Language English
    Publishing date 2021-03-06
    Publishing country United States
    Document type Journal Article
    ZDB-ID 603363-5
    ISSN 1573-7438 ; 0049-4747
    ISSN (online) 1573-7438
    ISSN 0049-4747
    DOI 10.1007/s11250-021-02632-3
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  4. Article: Estimation of (Co)Variance components and genetic parameters of fibre traits in Rambouillet sheep using multi-trait analysis

    Ahmad, Sheikh Firdous / Khan, Nusrat Nabi / Chakraborty, Dibyendu / Rather, Mubashir Ali / Shanaz, Syed / Alam, Safeer / Ganai, Nazir Ahmad

    Tropical animal health and production. 2021 Mar., v. 53, no. 1

    2021  

    Abstract: The present study aimed to estimate the genetic parameters of different fibre traits, viz., greasy fleece weight, staple length, and fibre diameter in Rambouillet sheep population using a multi-trait animal model. Data, spanning over 10 years (1998–2007) ...

    Abstract The present study aimed to estimate the genetic parameters of different fibre traits, viz., greasy fleece weight, staple length, and fibre diameter in Rambouillet sheep population using a multi-trait animal model. Data, spanning over 10 years (1998–2007) and pertaining to fibre traits at first clip, were collected for a total of 4186 Rambouillet sheep maintained at an organized farm. (Co)Variance structure and genetic parameters were estimated using a multi-trait animal model. The genetic analysis of data was performed based on restricted maximum likelihood (REML) procedure using WOMBAT software. The model incorporated sex of lamb (i = 1, 2), year of birth (j = 1–10), season of birth (k = 1–2), and litter size (l = 1–2) as fixed effects while direct additive genetic and maternal genetic effects were included as random effects. The direct additive genetic heritability estimates were 0.120±0.034, 0.136±0.037, and 0.356±0.070 for greasy fleece weight, staple length, and fibre diameter, respectively. The maternal genetic heritability of all fibre traits under study was very low. Additive genetic correlation was positive and low between greasy fleece weight and staple length; and between staple length and fibre diameter. In conclusion, fibre diameter was moderately heritable which implies that selection may lead to moderate improvement in this trait. The results from the present study will help in formulating optimal breeding plans for improvement of fibre traits in Rambouillet sheep.
    Keywords Rambouillet ; animal health ; animal models ; computer software ; farms ; fleece ; genetic analysis ; genetic correlation ; heritability ; litter size ; sheep ; staple (fibers) ; variance
    Language English
    Dates of publication 2021-03
    Size p. 190.
    Publishing place Springer Netherlands
    Document type Article
    Note NAL-AP-2-clean
    ZDB-ID 603363-5
    ISSN 1573-7438 ; 0049-4747
    ISSN (online) 1573-7438
    ISSN 0049-4747
    DOI 10.1007/s11250-021-02637-y
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    In stock of ZB MED Bonn / Germany

    Z 2667: Show issues

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  5. Article: Multivariate quantitative genetic analysis of body weight traits in Corriedale sheep

    Ahmad, Sheikh Firdous / Khan, Nusrat Nabi / Ganai, Nazir Ahmad / Shanaz, Syed / Rather, Mubashir Ali / Alam, Safeer

    Tropical animal health and production. 2021 June, v. 53, no. 2

    2021  

    Abstract: In the present study, an attempt was made to elucidate the genetic parameters for body weight traits of lambs from Corriedale sheep population at different ages. Data were collected from 6874 lambs born over a span of 49 years from 1969 to 2017. The ... ...

    Abstract In the present study, an attempt was made to elucidate the genetic parameters for body weight traits of lambs from Corriedale sheep population at different ages. Data were collected from 6874 lambs born over a span of 49 years from 1969 to 2017. The traits under study included body weight at birth (BW), weaning (WW), 6 months of age (6MW), 9 months of age (9MW) and yearling stage (YW). Data were statistically analyzed using restricted maximum likelihood (REML) algorithm in WOMBAT program. A multi-variate animal model was fitted to the data incorporating season and period of lambing, sex of lamb and litter size as fixed effects. Variance and covariance components were estimated using the animal model after incorporating direct additive genetic effect of animal as random factor. Genetic and phenotypic correlations with corresponding standard errors were also estimated. The heritability estimates for BW, WW, 6MW, 9MW and YW were 0.130 ± 0.023, 0.300 ± 0.029, 0.292 ± 0.030, 0.191 ± 0.025 and 0.169 ± 0.024, respectively. The genetic correlation between different traits under study was high, except between BW and 9MW for which the estimate was moderate. Phenotypic correlation ranged from low to high for different trait combinations. Among different traits under study, only two traits showed moderate heritability i.e. WW and 6MW while heritability of other traits was low. Both these traits showed high correlation with all subsequent traits. Selection programme for Corriedale sheep should be based on WW which is expressed early in life and shall lead to moderate genetic response to selection.
    Keywords Corriedale ; additive gene effects ; algorithms ; animal health ; animal models ; body weight ; covariance ; genetic analysis ; genetic correlation ; heritability ; litter size ; phenotype ; phenotypic correlation ; variance ; yearlings
    Language English
    Dates of publication 2021-06
    Size p. 197.
    Publishing place Springer Netherlands
    Document type Article
    Note NAL-AP-2-clean
    ZDB-ID 603363-5
    ISSN 1573-7438 ; 0049-4747
    ISSN (online) 1573-7438
    ISSN 0049-4747
    DOI 10.1007/s11250-021-02632-3
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    In stock of ZB MED Bonn / Germany

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  6. Article: Effect of Inbreeding Coefficient on Growth and Fitness Traits in a Closed Flock of Corriedale Sheep

    Nabi, Nusrat / Ganai, Nazir Ahmad / Shanaz, Syed / Aalam, Safeer / Shabir, Mir / Majid, Ruksana / Bukhari, Saba / Mir, Shakeel Ahmad / Hamadani, Ambreen / Rather, Mubashir Ali

    Indian journal of animal research. 2022 May, v. 56, no. 5

    2022  

    Abstract: The corriedale sheep breed was imported into J and K during sixties for use in improvement of local sheep and are maintained at Mountain Research Station of Sheep and Goat, SKUAST-K. The animals over the years were allowed to mate within the selected ... ...

    Abstract The corriedale sheep breed was imported into J and K during sixties for use in improvement of local sheep and are maintained at Mountain Research Station of Sheep and Goat, SKUAST-K. The animals over the years were allowed to mate within the selected animals of the flock as there was hardy any fresh importation of exotic animals from last 49 years due to which closed flock population was established within the farm. This has led to apprehensions over the loss of genetic diversity through years. The present study was to undertaken to evaluate the performance of Corriedale sheep under temperate climate and to estimate the inbreeding coefficient and its effect on growth and fitness traits of Corriedale sheep maintained at Mountain Research Centre for Sheep and Goat (MRCSG), F.V.Sc and A.H, SKUAST-K Shuhama, Kashmir. The information on performance and pedigree spanning over a period of 49 years (1969–2017) was collected and utilized for the study. The traits studied were birth weight (BW), weaning weight (WW), 6 months weight (6MW), 9 months weight (9MW) and 12 months weight (12MW) age at first lambing (AFL), litter size (LS), total lambs born per ewe (TLB) and survival rate (SR). The averages estimates for BW, WW, 6MW, 9MW, 12MW, AFL, LS, TLB and SR were 3.72±0.01 kg, 13.31±0.07 kg, 18.65±0.05 kg, 22.15±0.04 kg, 25.84±0.06 kg 807.20±4.34 days, 1.08±0.00, 4.83±0.03 and 80.76±1.98, respectively. The overall inbreeding coefficient (F) and proportion of population inbred (per cent) for Corriedale sheep were 18.3 and 43.3, respectively. The increased inbreeding coefficient had negative impact and highly significant (p<0.01) on all the traits under study except LS. The increased inbreeding coefficient (F) also had a negative impact on all the traits under study. With increase in the level of inbreeding there was a decrease in total body weight traits, lambs born per ewe and survival rate where as age at first lambing was increasing with the increase. he results indicated as decrease of 0.25 kg, 1.45 kg, 5.04 kg, 5.53 kg and 5.48 kg in body weight of the animals at birth, weaning weight, six months, nine months and twelve months from 1969–2017. To overcome the negative impact of inbreeding coefficient in the flock introduction of genetic variability through importation of Corriedale germplasm into the farm is highly recommended.
    Keywords Corriedale ; animal research ; birth weight ; ewes ; farms ; flocks ; genetic variation ; germplasm ; litter size ; pedigree ; survival rate ; temperate zones ; India
    Language English
    Dates of publication 2022-05
    Size p. 525-530.
    Publishing place Agricultural Research Communication Centre
    Document type Article
    ISSN 0976-0555
    DOI 10.18805/IJAR.B-4254
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  7. Article ; Online: Estimation of (Co)Variance components and genetic parameters of fibre traits in Rambouillet sheep using multi-trait analysis.

    Ahmad, Sheikh Firdous / Khan, Nusrat Nabi / Chakraborty, Dibyendu / Rather, Mubashir Ali / Shanaz, Syed / Alam, Safeer / Ganai, Nazir Ahmad

    Tropical animal health and production

    2021  Volume 53, Issue 1, Page(s) 190

    Abstract: The present study aimed to estimate the genetic parameters of different fibre traits, viz., greasy fleece weight, staple length, and fibre diameter in Rambouillet sheep population using a multi-trait animal model. Data, spanning over 10 years (1998-2007) ...

    Abstract The present study aimed to estimate the genetic parameters of different fibre traits, viz., greasy fleece weight, staple length, and fibre diameter in Rambouillet sheep population using a multi-trait animal model. Data, spanning over 10 years (1998-2007) and pertaining to fibre traits at first clip, were collected for a total of 4186 Rambouillet sheep maintained at an organized farm. (Co)Variance structure and genetic parameters were estimated using a multi-trait animal model. The genetic analysis of data was performed based on restricted maximum likelihood (REML) procedure using WOMBAT software. The model incorporated sex of lamb (i = 1, 2), year of birth (j = 1-10), season of birth (k = 1-2), and litter size (l = 1-2) as fixed effects while direct additive genetic and maternal genetic effects were included as random effects. The direct additive genetic heritability estimates were 0.120±0.034, 0.136±0.037, and 0.356±0.070 for greasy fleece weight, staple length, and fibre diameter, respectively. The maternal genetic heritability of all fibre traits under study was very low. Additive genetic correlation was positive and low between greasy fleece weight and staple length; and between staple length and fibre diameter. In conclusion, fibre diameter was moderately heritable which implies that selection may lead to moderate improvement in this trait. The results from the present study will help in formulating optimal breeding plans for improvement of fibre traits in Rambouillet sheep.
    MeSH term(s) Animals ; Birth Weight ; Body Weight ; Female ; Litter Size/genetics ; Phenotype ; Pregnancy ; Sheep/genetics ; Sheep, Domestic/genetics ; Wool
    Language English
    Publishing date 2021-03-03
    Publishing country United States
    Document type Journal Article
    ZDB-ID 603363-5
    ISSN 1573-7438 ; 0049-4747
    ISSN (online) 1573-7438
    ISSN 0049-4747
    DOI 10.1007/s11250-021-02637-y
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  8. Article: Genetic evaluation of wool traits of Kashmir Merino sheep in organized farms

    Rather, Mubashir Ali / Shanaz, S / Ganai, N.A / Bukhari, Saba / Hamadani, Ambreen / Nabi Khan, Nusrat / Yousuf, Saleem / Baba, Ashraf / Raja, T.A / Khan, H.M

    Small ruminant research. 2019 Aug., v. 177

    2019  

    Abstract: The present study was carried on 4174 records of Kashmir Merino breed maintained at Government Sheep Breeding Farms; Kralapathri and Gowbal, Kashmir from 1997 to 2017. The mixed linear model was used for analysis with sire as a random effect and period, ... ...

    Abstract The present study was carried on 4174 records of Kashmir Merino breed maintained at Government Sheep Breeding Farms; Kralapathri and Gowbal, Kashmir from 1997 to 2017. The mixed linear model was used for analysis with sire as a random effect and period, gender, farm, type of birth and parity as fixed effects. The averages were 0.77 ± 0.01 kg, 0.83 ± 0.01 kg, 20.41 ± 0.01 μ and 3.96 ± 0.02 cm for greasy fleece yield of first clip (GFY-1), greasy fleece yield of second clip (GFY-2), fiber diameter (FD) and staple length (SL). Highest and lowest CVs (%) were observed for GFY-2 (33.73%) and FD (2.26%), respectively. The least-squares means were 0.82 ± 0.05 kg, 0.80 ± 0.05 kg, and 3.86 ± 0.14 cm and 20.33 ± 0.05 μ for GFY-1, GFY-2, SL and FD, respectively. The sire and period of birth had significant effects while effect of birth type and dam’s parity was non-significant for all traits. The effects of sex and farm were significant on wool quality and yield traits, respectively. Heritability estimates were 0.61 ± 0.08, 0.47 ± 0.04, 0.23 ± 0.04, and 0.66 ± 0.10 for GFY-1, GFY-2, FD and SL, respectively. The results indicate that there is adequate genetic variability within the breed which can be used for further improvement of this breed.
    Keywords Merino ; dams (mothers) ; farms ; fleece ; gender ; genetic variation ; heritability ; least squares ; linear models ; sheep ; sires ; staple (fibers) ; wool ; India
    Language English
    Dates of publication 2019-08
    Size p. 14-17.
    Publishing place Elsevier B.V.
    Document type Article
    ZDB-ID 286928-7
    ISSN 0921-4488
    ISSN 0921-4488
    DOI 10.1016/j.smallrumres.2019.06.003
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    Z 4801: Show issues

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