Genetic parameters for direct and maternal effects on weights and ultrasonic muscle and fat depth of lambs

Larsgard, Anne Guro; Olesen, Ingrid

doi:10.1016/s0301-6226(98)00134-1

Cited by 53 publications

(51 citation statements)

References 17 publications

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“…Maternal heritability in the best model was 0.18, which is similar to the findings of Larsgard and Olesen (1998) in Norwegian sheep, Abegaz et al (2007) in Horro sheep and Vatankhah and Talebi (2008) in Lori-Bakhtiari sheep.…”

Section: Resultssupporting

confidence: 80%

(Co)variance components and genetic parameters for growth traits in Arabi sheep using different animal models

Shokrollahi¹,

Baneh²

2012

Genet. Mol. Res.

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ABSTRACT. The objective of the present study was to estimate genetic parameters for body weight at different ages in Arabi sheep using data collected from 1999 to 2009. Investigated traits consisted of birth weight (N = 2776), weaning weight (N = 2002) and weight at six months of age (N = 1885). The data were analyzed using restricted maximum likelihood analysis, by fitting univariate and multivariate animal models. All three weight traits were significantly influenced by birth year, sex and birth type. Age of dam only significantly affected birth weight. Log-likelihood ratio tests were conducted to determine the most suitable model for each growth trait in univariate analyses. Direct and total heritability estimates for birth weight, weaning weight and weight at six months of age (based on the best model) were 0.42 and 0.16 (model 4), 0.38 and 0.13 (model 4) and 0.14 and 0.14 (model 1), respectively. Estimation of maternal heritability for birth weight and weaning weight was 0.22 and 0.18, respectively. Genetic and phenotypic correlations among these traits were positive. Phenotypic correlations among traits were low to moderate. Genetic correlations among traits were positive and higher than the corresponding phenotypic correlations. Weaning weight had a strong and significant correlation with weight at six months of age (0.99). We conclude that selection can be made in animals based on weaning weight instead of the present practice of selection based on weight at six months.

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Section: Resultssupporting

confidence: 80%

(Co)variance components and genetic parameters for growth traits in Arabi sheep using different animal models

Shokrollahi¹,

Baneh²

2012

Genet. Mol. Res.

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“…The maternal heritability estimate for birth weight (0.33) obtained in this study was in accordance with the findings of Eftekhari-Shahroudi et al (2002) in Kermani sheep (0.33) and Larsgard and Olesen (1998) in Norwegian sheep (0.42). However, a very high estimate for this trait was reported by MiraeiAshtiani et al (2007) in Sangsari sheep (0.65).…”

Section: Birth Weightsupporting

confidence: 92%

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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“…In our study, about 8% (112/1375) of the dams had their own performance records and the average number of progeny per dam was 1.91, resulting in modest r dm for BFT, SBFT and MD (Table 3). On the other hand, Larsgard and Olesen (1998) reported very low but insignificant estimates for r dm of BFT and MD at pre-weaning and weaning. Maxa et al (2007) have reported the estimates of r dm for BFT, MD and LW as −0.69, −0.63 and −0.60, respectively.…”

Section: Discussionmentioning

confidence: 87%

“…Larsgard and Olesen (1998) have reported the estimates of c 2 for BFT and MD as 0.13 and 0.17 at pre-weaning, and 0.13 and 0.08 at weaning, respectively. The authors also reported c 2 values of 0.04, 0.08 and 0.10 for weight at birth, at pre-weaning and at weaning, respectively.…”

Section: Discussionmentioning

confidence: 99%

“…Hence, animal models, which ignore maternal effects, might result in upward bias in predicted response to selection due to the overestimation of direct heritability (Ghafouri-Kesbi and Baneh, 2012). Several studies have reported the genetic parameter estimates in sheep with direct and maternal effects (Larsgard and Olesen, 1998;Maniatis and Pollott, 2002;Maxa et al, 2007;Kushwaha et al, 2009;Gowane et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

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Bayesian inference of genetic parameters for ultrasound scanning traits of Kivircik lambs

Cemal

Karaman

Fırat

et al. 2017

Animal

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Ultrasound scanning traits have been adapted in selection programs in many countries to improve carcass traits for lean meat production. As the genetic parameters of the traits interested are important for breeding programs, the estimation of these parameters was aimed at the present investigation. The estimated parameters were direct and maternal heritability as well as genetic correlations between the studied traits. The traits were backfat thickness (BFT), skin + backfat thickness (SBFT), eye muscle depth (MD) and live weights at the day of scanning (LW). The breed investigated was Kivircik, which has a high quality of meat. Six different multi-trait animal models were fitted to determine the most suitable model for the data using Bayesian approach. Based on deviance information criterion, a model that includes direct additive genetic effects, maternal additive genetic effects, direct maternal genetic covariance and maternal permanent environmental effects revealed to be the most appropriate for the data, and therefore, inferences were built on the results of that model. The direct heritability estimates for BFT, SBFT, MD and LW were 0.26, 0.26, 0.23 and 0.09, whereas the maternal heritability estimates were 0.27, 0.27, 0.24 and 0.20, respectively. Negative genetic correlations were obtained between direct and maternal effects for BFT, SBFT and MD. Both direct and maternal genetic correlations between traits were favorable, whereas BFT-MD and SBFT-MD had negligible direct genetic correlation. The highest direct and maternal genetic correlations were between BFT and SBFT (0.39) and between MD and LW (0.48), respectively. Our results, in general, indicated that maternal effects should be accounted for in estimation of genetic parameters of ultrasound scanning traits in Kivircik lambs, and SBFT can be used as a selection criterion to improve BFT.

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Genetic parameters for direct and maternal effects on weights and ultrasonic muscle and fat depth of lambs

Cited by 53 publications

References 17 publications

(Co)variance components and genetic parameters for growth traits in Arabi sheep using different animal models

(Co)variance components and genetic parameters for growth traits in Arabi sheep using different animal models

Genetic parameter estimates for growth traits in Iran-Black sheep

Bayesian inference of genetic parameters for ultrasound scanning traits of Kivircik lambs

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