Genetic Parameter Estimates for Growth and Reproductive Trait of Sheep for Genetic Improvement and Designing Breeding Program in Ethiopia: A Review

Mekuriaw, Shigdaf; Haile, Aynalem

doi:10.4236/oalib.1100589

Cited by 7 publications

(9 citation statements)

References 18 publications

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“…The moderate to high heritability estimates for growth traits indicate that sufficient additive genetic variance existed for these traits, which could be used for selection within the population as was done in our CBBPs. Heritability estimates for growth traits are generally moderate to high (Duguma et al, 2002;Masood Tariq et al, 2010;Mekuriaw and Haile, 2014). However, these previous reports, unlike ours, are all based on on-station management where environmental variances are expected to be minimal.…”

Section: Inbreeding Heritability and Genetic Correlationmentioning

confidence: 53%

Community-based sheep breeding programs generated substantial genetic gains and socioeconomic benefits

Haile¹,

Getachew²,

Mirkena³

et al. 2020

Animal

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Community-based breeding programs (CBBPs) for small ruminants have been suggested as alternatives to centralised, government-controlled breeding schemes which have been implemented in many developing countries. An innovative methodological framework on how to design, implement and sustain CBBPs was tested in three sites in Ethiopia: Bonga, Horro and Menz. In these CBBPs, the main selection trait identified through participatory approaches was 6-month weight in all three sites. In Horro and Bonga, where resources such as feed and water permitted larger litter sizes, twinning rate was included. Ten-year (2009 to 2018) performance data from the breeding programs were analysed using Average Information Restricted Maximum Likelihood method (AI-REML). Additionally, the socioeconomic impact of CBBPs was assessed. Results indicated that 6-month weight increased over the years in all breeds. In Bonga, the average increase was 0.21 ± 0.018 kg/year, followed by 0.18 ± 0.007 and 0.11 ± 0.003 kg/year in Horro and Menz, respectively. This was quite substantial in an on-farm situation. The birth weight of lambs did not improve over the years in Bonga and Horro sheep but significant increases occurred in Menz. Considering that there was no direct selection on birth weight in the community flock, the increased weights observed in Menz could be due to correlated responses, but this was not the case in Bonga and Horro. The genetic trend for prolificacy over the years in both Bonga and Horro flocks was positive and significant (P < 0.01). This increase in litter size, combined with the increased 6-month body weight, increased income by 20% and farm-level meat consumption from slaughter of one sheep per year to three. The results show that CBBPs are technically feasible, result in measurable genetic gains in performance traits and impact the livelihoods of farmers.

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Section: Inbreeding Heritability and Genetic Correlationmentioning

confidence: 53%

Community-based sheep breeding programs generated substantial genetic gains and socioeconomic benefits

Haile¹,

Getachew²,

Mirkena³

et al. 2020

Animal

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“…Obviously, heritability and genetic correlations are important information among the factors determining genetic improvement in any trait (Mekuriaw and Haile, 2014). So, the first step for introducing a new selection criteria into a breeding programme is the calculation of the genetic parameters of the trait.…”

Section: Resultsmentioning

confidence: 99%

“…Knowledge of the particular trait and phase of the animals' growth, which is the basis for selection, is the most important one. The potential for genetic improvement is largely dependent on the genetic parameters of the growth weight trait upon which selection may be applied (Mekuriaw and Haile, 2014).…”

Section: Resultsmentioning

confidence: 99%

“…Additive genetic correlations quantify the levels of linkage and pleiotropy existing among additive loci determining the performances of two different traits (Mekuriaw and Haile, 2014).…”

Section: Resultsmentioning

confidence: 99%

“…Information of genetic parameter estimation for different traits is useful in formulating breeding programmes because these parameters determine the direction and magnitude of genetic improvement (Mekuriaw and Haile, 2014).…”

Section: Introductionmentioning

confidence: 99%

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Genetic parameters of traits associated with the growth curve in Segureña sheep

Lupi

León²,

Nogales

et al. 2016

Animal

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This paper studies the genetic importance of growth curve parameters and their relevance as selection criteria in breeding programmes of Segureño sheep. Logistic and Verhulst growth functions were chosen for their best fit to BW/age in this breed; the first showed the best general fit and the second the best individual fit. Live weights of 41 330 individuals from the historical archives of the National Association of Segureña Sheep Breeders were used in the analysis. The progeny of 1464 rams and 27 048 ewes were used to study the genetic and phenotypic parameters of growth curve parameters and derived traits. Reproductive management in the population consists in controlled natural mating inside every herd, with a minimum of 15% of the females fertilized by artificial insemination with fresh semen; with the purpose being the herd genetic connections, all herd genealogies are screened with DNA markers. Estimates of growth curve parameters from birth to 80 days were obtained for each individual and each function by the non-linear regression procedure using IBM SPSS statistics (version 21) with the Levenberg-Marquart estimation method. (Co)variance components and genetic parameters were estimated by using the REML/Animal model methodology. The heritability of mature weight was estimated as 0.41 ± 0.042 and 0.38 ± 0.021 with the logistic and Verhulst models, respectively, and the heritability of other parameters ranged from 0.41 to 0.62 and 0.37 to 0.61, with the models, respectively. A negative genetic correlation between mature weight and rate of maturing was found.

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Meta‐analysis of genetic parameters for growth traits in meat, wool and dual‐purpose sheep breeds in the world using a random‐effects model

Abasi‐Mousa

Varkoohi

Joezy

et al. 2022

Veterinary Medicine & Sci

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Background There is large variation in genetic parameters in literature for growth traits in sheep. Reliable estimation of genetic parameters is required for developing breeding programmes. Objectives The aim of this study was to aggregate results of different studies by meta‐analysis to improve reliability of estimated parameters. Methods In the current study, 221 papers that have been published between 1995 and 2021 were reviewed. Using a random‐effects model in the Comprehensive Meta‐Analysis software, direct and maternal heritabilities, as well as, genetic and phenotypic correlations between growth traits were estimated in meat (M), wool (W) and dual‐purpose (D) sheep breeds. The growth traits in this study were birth weight, 3‐month weight, 6‐month weight, 9‐month weight and yearling weight. Results The combined direct heritability was the lowest for birth weight (0.190 ± 0.004, 0.198 ± 0.003 and 0.196 ± 0.004 for M, W and D breeds, respectively) and the highest for yearling weight (0.264 ± 0.010, 0.304 ± 0.005 and 0.285 ± 0.020 for M, W and D breeds, respectively). The maternal heritability was the lowest for yearling weight (0.085 ± 0.003, 0.055 ± 0.002 and 0.052 ± 0.005 for M, W and D breeds, respectively) and the highest for 6‐month weight (0.240 ± 0.088, 0.164 ± 0.001 and 0.162 ± 0.006 for M, W and D breeds, respectively). The phenotypic and genetic correlations were lower between the weights measured at more distant intervals. The lowest genetic correlation was observed between birth weight and yearling weight (0.290 ± 0.051 for W breeds). Conclusions The small standard errors could indicate that the aggregation of results from different studies improved the reliability of estimated parameters and reduced range of 95% confidence intervals. Hence, the results could be used with greater level of confidence in sheep breeding programmes.

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Genetic Parameter Estimates for Growth and Reproductive Trait of Sheep for Genetic Improvement and Designing Breeding Program in Ethiopia: A Review

Abstract: Abstractbreed is nonexistence.

Cited by 7 publications

References 18 publications

Community-based sheep breeding programs generated substantial genetic gains and socioeconomic benefits

Community-based sheep breeding programs generated substantial genetic gains and socioeconomic benefits

Genetic parameters of traits associated with the growth curve in Segureña sheep

Meta‐analysis of genetic parameters for growth traits in meat, wool and dual‐purpose sheep breeds in the world using a random‐effects model

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