Direct and maternal genetic components of variance for growth traits in Nilagiri and Sandyno Sheep of South India

Venkataramanan, R.; Subramanian, A.; Sivaselvam, S.N.; Sivakumar, T.; Sreekumar, C.; Iyue, M.

doi:10.5958/0973-9718.2015.00069.0

Cited by 9 publications

(10 citation statements)

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“…For SMW, NMW, and YW, the additive direct heritability estimated from the best model (model 2) was 0.12, 0.14, and 0.13, respectively. The reported heritability estimates for 6-month body weight in the sheep breeds Chokla, Iran Black, Nilagiri, and Nellore are comparable to the current results [ 7 , 17 , 31 ]. Higher heritability estimates for SMW were reported in Lori [ 8 ], Nellore [ 9 ], Malapura [ 29 ], and Sangsari [ 39 ] sheep breeds, but low estimates were reported in Baluchi [ 5 ] and Sanjabi [ 40 ] lambs.…”

Section: Discussionsupporting

confidence: 88%

“…It was comparable with reported findings in various tropical sheep breeds [ 11 , 21 – 23 ]. However, this estimate was comparatively higher than those estimated in Malapura [ 6 ], Nilagiri [ 7 ], Corriedale [ 12 ], Kermani [ 24 ], Chokla [ 25 ], and Nellore [ 26 ] lambs. Higher heritability in Mecheri sheep was previously reported [ 27 ], in a study in which maternal effects evaluation was absent.…”

Section: Discussioncontrasting

confidence: 58%

“…The estimate from the current study was less than that for Nellore [ 9 ] and Malpura [ 6 , 22 ] sheep. Weaning weight in various sheep breeds was estimated to have lower heritability values [ 7 , 26 , 35 ]. Lamb weight at weaning had a lower heritability than lamb birth weight.…”

Section: Discussionmentioning

confidence: 99%

“…Higher heritability estimates for SMW were reported in Lori [ 8 ], Nellore [ 9 ], Malapura [ 29 ], and Sangsari [ 39 ] sheep breeds, but low estimates were reported in Baluchi [ 5 ] and Sanjabi [ 40 ] lambs. According to past findings in several sheep breeds, the heritability estimates for body weight at nine months and 12 months in Mecheri sheep are accurate [ 7 , 26 , 29 , 30 ]. The current estimates, however, were lower than those of different researchers in different sheep breeds [ 8 , 9 , 25 ].…”

Section: Discussionmentioning

confidence: 99%

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Development of selection strategies for genetic improvement in production traits of Mecheri sheep based on a Bayesian multi trait evaluation

Balasundaram,

Muralidharan,

Murali

et al. 2023

PLoS ONE

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The progression of genetic selection techniques to enhance farm animal performance traits is guided by the present level of genetic variation and maternal impact in each trait, as well as the genetic association between traits. This study was conducted on a population of Mecheri sheep maintained from 1980 to 2018 at Mecheri Sheep Research Station, Pottaneri, India, to determine variance and covariance components, as well as genetic parameters for various production performance traits. A total of 2616 lambs, produced by 1044 dams and 226 sires, were examined in the study and the production traits of Mecheri sheep assessed include birth weight (BW), weaning weight (WW), six-month weight (SMW), nine-month weight (NMW), and yearling weight (YW). The Bayesian approach, using the Gibbs sampler, analyzed six animal models with different combinations of additive direct and maternal additive effects. Direct genetics, maternal genetics, and residual effects models were the major contributors to total phenotypic variation for all the production traits studied. Direct heritability estimates of birth weight, WW, SMW, NMW, and YW were 0.25, 0.20, 0.12, 0.14, and 0.13, respectively. The maternal heritability estimated for BW, WW, SMW, NMW, and YW were 0.17, 0.10, 0.12, 0.14, and 0.14, respectively. The maternal effects had a major impact on the pre-weaning production traits. The genetic correlations estimated between different pairs of production traits studied ranged from 0.19 to 0.93. The body weight at birth exhibited a higher genetic relationship with weaning weight than post-weaning growth characteristics, and the genetic correlation between weaning weight and post-weaning attributes was moderate to high (0.52 to 0.72). Based on the additive genetic variance in weaning weight and the correlation estimates of weaning weight with post-weaning traits, weaning weight was proposed as a selection criterion for improving growth traits in Mecheri sheep.

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Section: Discussionsupporting

confidence: 88%

Section: Discussioncontrasting

confidence: 58%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Development of selection strategies for genetic improvement in production traits of Mecheri sheep based on a Bayesian multi trait evaluation

Balasundaram,

Muralidharan,

Murali

et al. 2023

PLoS ONE

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“…The lowest mean birth weight among Indian breeds was 1.29 kg for Keezhakkaraisal (Ganesakale and Rathnasabapathy, 1973) and the highest as 3.55 kg for Muzaffarnagri sheep (Dass et al, 2014). W hile the birth weight of Nilagiri sheep ranged from 2.37 to 3.15 kg, the reported birth weight for Nilagiri Synthetic sheep (Sandyno) ranged from 2.56 kg to 2.81 kg (Rajendran, 2005;Venkataramanan et al, 2015). In this investigation, the higher range of 3.15 kg in birth weight was observed when the ewes weight averaged between 35 to 36 kg and thereafter the difference was not much appreciated as the no of observations were also less.…”

mentioning

confidence: 99%

Clustering of Dam’s Body Weight Based on Birth Weight of Lambs in Nilagiri Sheep

Geetha¹,

Chitra²,

Karthickeyan³

et al. 2023

IJAR

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The population of Nilagiri breed of Sheep is threatened and required micro breeding strategy for conservation and genetic improvement. Data on 4,619 Nilagiri lambs born during the 28 years (1993-2021) at the Sheep Breeding Research Station (SBRS), Sandynallah of the Nilgiris district, Tamil Nadu, India were utilized for this investigation. Data on birth weight of lamb along with dam’s body weight at the time of lambing were collected. Relationship between different body weights of dam was investigated in terms of lamb’s birth weight using one-way ANOVA followed by post hoc test for different dam body weight pairwise comparison. Heatmap was drawn for P values between different dam’s body weights aiding in visualization of the possible compatibility between body weights of dam. The birth weight of lambs positively correlated with that of dam’s body weight. Heat map visual analysis revealed five different clusters viz. less than 23.00 kg, 23.01-26.00 kg, 26.01-29.00 kg, 29.01-32.00 kg and greater than 32.01 kg sets of patterns. This was the first study in sheep breed for applying heatmap tool for growth trait analysis.

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Estimates of direct and maternal (co)variance components as well as genetic parameters of growth traits in Nellore sheep

Kumar

Gangaraju

et al. 2017

Trop Anim Health Prod

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In the present study, (co)variance components and genetic parameters in Nellore sheep were obtained by restricted maximum likelihood (REML) method using six different animal models with various combinations of direct and maternal genetic effects for birth weight (BW), weaning weight (WW), 6-month weight (6MW), 9-month weight (9MW) and 12-month weight (YW). Evaluated records of 2075 lambs descended from 69 sires and 478 dams over a period of 8 years (2007-2014) were collected from the Livestock Research Station, Palamaner, India. Lambing year, sex of lamb, season of lambing and parity of dam were the fixed effects in the model, and ewe weight was used as a covariate. Best model for each trait was determined by log-likelihood ratio test. Direct heritability for BW, WW, 6MW, 9MW and YW were 0.08, 0.03, 0.12, 0.16 and 0.10, respectively, and their corresponding maternal heritabilities were 0.07, 0.10, 0.09, 0.08 and 0.11. The proportions of maternal permanent environment variance to phenotypic variance (Pe) were 0.07, 0.10, 0.07, 0.06 and 0.10 for BW, WW, 6MW, 9MW and YW, respectively. The estimates of direct genetic correlations among the growth traits were positive and ranged from 0.44(BW-WW) to 0.96(YW-9MW), and the estimates of phenotypic and environmental correlations were found to be lower than those of genetic correlations. Exclusion of maternal effects in the model resulted in biased estimates of genetic parameters in Nellore sheep. Hence, to implement optimum breeding strategies for improvement of traits in Nellore sheep, maternal effects should be considered.

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Direct and maternal genetic components of variance for growth traits in Nilagiri and Sandyno Sheep of South India

Cited by 9 publications

References 0 publications

Development of selection strategies for genetic improvement in production traits of Mecheri sheep based on a Bayesian multi trait evaluation

Development of selection strategies for genetic improvement in production traits of Mecheri sheep based on a Bayesian multi trait evaluation

Clustering of Dam’s Body Weight Based on Birth Weight of Lambs in Nilagiri Sheep

Estimates of direct and maternal (co)variance components as well as genetic parameters of growth traits in Nellore sheep

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