Estimation of genetic parameters for body weights of Kurdish sheep in various ages using multivariate animal models

Abstract. Calving records from the Animal Breeding Centre of Iran collected from January 1995 to December 2007 and comprising 217973 calving events of Holsteins from 704 dairy herds were analysed using univariate and bivariate linear animal models to estimate heritabilities and genetic correlations for energy-corrected 305-d milk yield (ECM) in the first three lactations of Holstein cows. Genetic trends were obtained by regressing yearly mean estimates of breeding values on calving year. Average ECM increased from parity 1 through parity 3. Estimates of heritabilities were from 0.14 to 0.21 for ECM and decreased over the parities. The greatest genetic correlations were between ECM2 and ECM3 (0.96), and the greatest phenotypic correlations were between ECM1 and ECM2 (0.57) and ECM2 and ECM3 (0.57). The high and positive genetic correlations between ECM traits at different lactations are evidence for common genetic and physiological mechanism controlling these traits. There were positive and increasing phenotypic and genetic trends for ECM over the years (P<0.001). Higher heritability of the ECM in the first parity along with the high genetic correlations between first-lactation ECM with these traits in other lactations shows that higher potential exists for selecting animals for ECM based on their first parity records.

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Estimates of genetic parameters for growth traits of local Hamra breed threatened with extinction in southwestern arid rangeland of Algeria

Biotechnology in Animal Husbandry ◽

10.2298/bah1804433y ◽

2018 ◽

Vol 34 (4) ◽

pp. 433-441

Author(s):

Houari Yerou ◽

Hakim Ouldouelhadj ◽

Abdelrahmane Berber ◽

Amine Mokadem ◽

Bachir Koudad

Keyword(s):

Animal Models ◽

Data Base ◽

Fixed Effects ◽

Genetic Parameters ◽

Growth Traits ◽

Genetic Correlations ◽

Phenotypic Correlations ◽

Body Weights ◽

Covariance Components ◽

Variance And Covariance Components

The data base for body weights and growths of 411 Hamra lambs were used to estimate genetic parameters. These lambs were obtained from 31 rams and 493 ewes between 2012 and 2017. Traits analysed were weights at birth (BW), 30 days (W30), 90 days (W90) of age, and average daily gains from 10 to 30 (ADG10-30) and30-90 (ADG30-90) days. REML estimates of variance and covariance components were obtained assuming animal models that included the fixed effects for year-type of birth (2012 single, 2012 twin, . ., 2017 single, 2017 twin), sex (male, female), and ewes age at lambing (< 18, 18-30, 30-42, 42-54, >54 months). Heritabilities were 0.12, 0.06 and 0.11 respectively for BW, W3Oand W90and the average daily gains were 0.05 and 0.17 for ADG0-30and ADG30-90. The estimates of genetic correlations showed no genetic antagonisms among the growth traits. The genetic correlations estimated were positive and medium to high, except those between ADG30-90 and ADG0-30 and between ADG30-90 and W30 which were slightly negative. Phenotypic correlations were positive and ranged from 0.12 to 0.85. They were high between adjacent weights and between ADG and their corresponding weights.

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Estimation of Genetic Parameters for Body Weights and Body Measurements of Korean Cattle

Journal of Animal Science and Technology ◽

10.5187/jast.2002.44.2.201 ◽

2002 ◽

Vol 44 (2) ◽

pp. 201-206

Keyword(s):

Genetic Parameters ◽

Body Measurements ◽

Korean Cattle ◽

Body Weights ◽

Estimation Of Genetic Parameters

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Estimation of genetic parameters for lambing ease, birthweight and gestation length in Australian sheep

Animal Production Science ◽

10.1071/an14129 ◽

2016 ◽

Vol 56 (5) ◽

pp. 934 ◽

Cited By ~ 8

Author(s):

L. Li ◽

D. J. Brown

Keyword(s):

Animal Models ◽

Environmental Effects ◽

Genetic Parameters ◽

Genetic Correlations ◽

Gestation Length ◽

Phenotypic Variance ◽

Full Dataset ◽

Australian Sheep ◽

Using Data ◽

Estimation Of Genetic Parameters

This study presents estimates of genetic parameters for lambing ease (LE), birthweight (BW) and gestation length (GL) in Australian terminal sire sheep breeds using data from the Sheep Genetics LAMBPLAN database. LE was scored on lambs on a 1–5 scale, with 1 being no assistance and 5 being other such as special veterinary assistance. The full dataset consisted of 43 448 records on LE and its two subsets (the single and twin subsets) based on the birth type of the litter were analysed. Four models with different combinations of random effects consisting of direct genetic, maternal genetic and maternal permanent environmental effects were compared. All traits were analysed using linear animal models and linear sire models with LE further analysed by threshold sire models for all datasets to evaluate the influence of datasets and models on the estimation of genetic parameters. The results showed that multiple-born lambs had shorter GL, less BW and less lambing difficulty than single-born lambs. Lambing difficulty decreased with the increase of dam age from 1.5 to 4.5 years, and then increased afterwards. Genetic parameters using linear animal models were similar to those using linear sire models for all traits. Phenotypic variance and direct heritability were higher for single-born lambs compared with twin-born lambs. No significant maternal permanent environmental effect was detected for LE. Based on results using linear animal models with the full dataset, the direct heritabilities were 0.06 ± 0.01, 0.15 ± 0.01 and 0.52 ± 0.02, the maternal heritabilities were 0.03 ± 0.01, 0.15 ± 0.01 and 0.13 ± 0.02 for LE, BW and GL, respectively. The proportions of maternal permanent environmental effects to the total variances were 0.13 ± 0.01 for BW. Low to moderate direct genetic correlations of 0.31 ± 0.09 (LE and BW), 0.24 ± 0.11 (LE and GL) and 0.08 ± 0.08 (BW and GL) were estimated using tri-variate analysis from the full dataset, indicating the trend that lambs with greater BW and longer GL would result in more lambing difficulty.

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