Genetic parameters for lamb weight at different ages and wool production in Baluchi sheep

Yazdi, Mehdi Hossein; Engström, Göran; Näsholm, A.; Johansson, Kjell; Jorjani, H.; Liljedah, L.-E.

doi:10.1017/s1357729800016556

Cited by 101 publications

(101 citation statements)

References 18 publications

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“…Selecting for either birth weight or weaning weight without changing ewe weight would be difficult. This is in agreement with other reports (Nasholm & Danell, 1996;Yazdi et al, 1997;Mousa et al, 1999).…”

Section: Resultssupporting

confidence: 94%

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Phenotypic and genetic relationships between lamb and ewe traits for the Sabi sheep of Zimbabwe

Matika¹,

Wyk²,

Erasmus³

et al. 2001

SA J. An. Sci.

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Genetic and phenotypic correlations were estimated between lamb and ewe traits in a flock of Sabi sheep reared at the Matopos Research Station. Direct additive estimates of heritability were: 0.28 ± 0.04; 0.17 ± 0.00; 0.25 ± 0.01; 0.39 ± 0.01; 0.59 ± 0.01; 0.50 ± 0.01; 0.68 ± 0.03; 0.12 ± 0.003; 0.25 ± 0.01; 0.11 ± 0.00; 0.12 ± 0.00; for birth weight, weaning weight (120 days), 12 month weight, 18 month weight, ewe mating weight, post partum weight, ewe weight at weaning of lamb, total weight of lamb weaned, slaughter weight, hot and cold carcass weights respectively. Genetic correlations between birth weight and other weights to 18 months were high (0.75-0.85), whilst the relationship between weaning, 12 month and 18 month weight was close to unity. The genetic correlation between birth weight and ewe weights (mating, post-partum and dam weight at weaning of lamb) were moderate viz. 0.51 ± 0.08, 0.40 ± 0.09, 0.49 ± 0.07 respectively and were close to unity at 18 months of age viz. 0.96 ± 0.02, 0.92 ± 0.03, and 0.84 ± 0.03 respectively. Total weight of lamb weaned was moderately correlated to birth weight (r g = 0.46 ± 0.15) but tended to be highly correlated with 18 month weight (0.92 ± 0.10) and ewe weights (0.75 ± 0.09-0.91 ± 0.07). The genetic correlation between birth weight and slaughter and carcass weight was moderate and was high at 18 months. The heritability estimates from a univariate logit transformed analysis for fertility, prolificacy and lamb survival were 0.08 ± 0.04, 0.22 ± 0.03, and 0.01 ± 0.02 respectively. The genetic correlation between fertility and lamb weight and ewe weights was low (-0.08 ± 0.004, to 0.06 ± 0.02) and some estimates had large standard errors. The genetic correlation between prolificacy and birth weight was close to zero. The genetic correlations between prolificacy and weaning weight, 12 month weight, 18 month weight, ewe mating, post-partum and ewe weight at weaning were 0.07 ± 0.02; 0.12 ± 0.00; 0.07 ± 0.02; 0.22 ± 0.00; 0.13 ± 0.00; 0.24 ± 0.00 respectively, and that between fertility and prolificacy was negative (-0.17 ± 0.07). Genetic correlations between lamb survival and birth weight, weaning weight, 12 month weight, 18 month weight and total weight of lamb weaned were 0.18 ± 0.00, 0.26 ± 0.00, 0.15 ± 0.00, 0.15 ± 0.00, 0.13 ± 0.00 respectively. Selection for birth weight and total weight of lamb weaned have possible uses in a selection index for the Sabi flock. _______________________________________________________________________________________

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Section: Resultssupporting

confidence: 94%

“…Fogarty (1995) reported lower genetic (0.07-0.32) and phenotypic correlations between birth weight and later weights. The largest relationships were found between chronologically adjacent weights, which is similar to other reports (Fogarty, 1995;Yazdi et al, 1997;El Fadili et al, 2000).…”

Section: Resultssupporting

confidence: 91%

Phenotypic and genetic relationships between lamb and ewe traits for the Sabi sheep of Zimbabwe

Matika¹,

Wyk²,

Erasmus³

et al. 2001

SA J. An. Sci.

View full text Add to dashboard Cite

show abstract

“…The estimate of maternal heritability for weaning weight from our data (m 2 00.05) was within the range of reported estimates for other sheep breeds (Yazdi et al 1997;Notter 1998;Ozcan et al 2005;Mandal et al 2008;Miraei-Ashtiani et al 2007). However, El Fadili et al (2000), Abegaz et al (2002), Safari et al (2005), and Savar-Sofla et al (2011) obtained higher estimates (0.10Á0.24) than the present study.…”

Section: Weaning Weightsupporting

confidence: 86%

“…A number of studies have demonstrated that maternal effects are substantial for growth-related traits in sheep and the inclusion of maternal effects in animal models has an important effect on the estimates of direct heritability (Maria et al 1993;Ozcan et al 2005;Mandal et al 2006;Rashidi et al 2008;Baneh et al 2010). Genetic and environmental relationships between direct and maternal effects for growth have often varied from moderately positive to highly negative in various sheep breeds (Maria et al 1993;Tosh & Kemp 1994;Snyman et al 1995;Nasholm & Danell 1996;Yazdi et al 1997;Notter 1998). Hence, to achieve optimum progress in a selection program, both direct and maternal components should be taken into account, especially if there is an antagonistic relationship between them.…”

Section: Introductionmentioning

confidence: 99%

Genetic parameter estimates for growth traits in Iran-Black sheep

Kamjoo

Baneh

Yousefi

et al. 2013

Journal of Applied Animal Research

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The present study was conducted to estimate variance components and genetic parameters for growth traits of Iran-Black sheep, maintained at the Abbasabad sheep breeding station, located in northeast of Mashhad, (Razavi Khorasan province of Iran) over a period of 24 years (1981 through 2004). Records of 4607 lambs descended from 155 rams, and 1227 ewes were used in the study. Traits included for the present study were birth weight (BW), weaning weight (WW), weight at 6 months (W6), weight at 9 months (W9), and yearling weight (YW). Analyses were carried out by restricted maximum likelihood (REML) fitting an animal model and ignoring or including maternal genetic or permanent environmental effects. Six different animal models were fitted for all traits. The most appropriate model was chosen after testing the improvement of the log-likelihood values. Heritability estimates for weight at birth; weaning; and 6, 9, and 12 months of age were 0.04, 0.14, 0.16, 0.19, and 0.18, respectively. Maternal heritability of body weight declined from 0.33 at birth to 0.04 at six months of age. The maternal permanent environmental component accounted for 6% to 15% to the total variance for all traits under study. The direct-maternal genetic correlation (r am ) was positive for all traits and ranged from 0.3690.27 for BW to 0.9990.98 for YW, but was never significant. The results showed that modest rates of genetic progress appear possible for all weights. Results also suggest that maternal additive effects were only important in early stages of growth, whereas a permanent environmental maternal effect existed at all ages up to 12 months of age, probably as a carry-over effect of maternal influences present at weaning. Direct genetic correlations (r a1,a2 ) between traits were positive and ranged from 0.82 (BW-WW) to 0.99 (W6-YW). The estimates of correlation between permanent environmental maternal effect among traits were close to those of r a1,a2 . Phenotypic and environmental correlations for all traits were generally lower than direct genetic correlations.

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“…Due to the fact that the supply of meat from sheep does not cover the demand, a breeding scheme is needed to increase the efficiency of sheep production by improving litter size, body conformation, lamb weight and milk yield (Yazdi et al, 1997). Profitability of sheep production for meat depends to a great extent on lamb weight, so the selection objective should concentrate on these traits (Tosh & Kemp, 1994).…”

Section: Introductionmentioning

confidence: 99%

Association of the polymorphism in the 5’ flanking region of the ovine IGF-I gene with growth traits in the Baluchi sheep

et al. 2010

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The insulin-like growth factor 1 (IGF-I) gene has been described in several studies as a candidate gene for growth traits in farm animals. The present preliminary study attempts to establish associations between growth traits and genetic polymorphisms at the 5' flanking region s IGF-I in the Baluchi sheep. The DNA of 102 sheep of the indigenous Iranian Baluchi breed was evaluated. Polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis of the 5' flanking region (Exon1) of the ovine IGF-I gene revealed three banding patterns (genotypes) named as A/A, A/B and B/B. The evaluation of an association effect between these SSCP patterns with birth weight (BW), weaning weight (WW), and average daily gain from birth to weaning (GBW), weaning to six month (GWS) and from six month to yearling age (GSY) suggest a positive effect of pattern (Genotype) A/B with GBW and weaning weight (WW). Pattern (Genotype) B/B had a superior birth weight when compared to those of individuals with other patterns. Moreover, the A/A pattern (Genotype) appeared favourable for live weight at yearling age. These results confirmed the potential usefulness of this gene in marker-assisted selection programmes for sheep breeding. ________________________________________________________________________________

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Genetic parameters for lamb weight at different ages and wool production in Baluchi sheep

Cited by 101 publications

References 18 publications

Phenotypic and genetic relationships between lamb and ewe traits for the Sabi sheep of Zimbabwe

Phenotypic and genetic relationships between lamb and ewe traits for the Sabi sheep of Zimbabwe

Genetic parameter estimates for growth traits in Iran-Black sheep

Association of the polymorphism in the 5’ flanking region of the ovine IGF-I gene with growth traits in the Baluchi sheep

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