Estimates of genetic parameters and breeding values for New Zealand and Australian Angus cattle

1995 ◽  
Vol 46 (6) ◽  
pp. 1219 ◽  
Author(s):  
K Meyer

Genetic parameters and adjustment factors for birth, weaning, yearling and final weight were estimated for the New Zealand Angus population, fitting an animal model including maternal genetic and permanent environmental effects as additional random effects. Overall, pooled covariance matrices agreed well with those for Australian Angus, though heritability estimates for birth weight were somewhat lower than in Australian Angus. BREEDPLAN estimates of breeding values and their accuracies were obtained for each population separately. Correlations between estimates for sires with accurate proofs in both countries agreed with their expectations, giving no indication of a genotype x environment interaction. A joint genetic evaluation using adjustment factors specific to each country but the same covariance matrices is recommended.

2012 ◽  
Vol 52 (1) ◽  
pp. 1 ◽  
Author(s):  
Gilbert Jeyaruban ◽  
Bruce Tier ◽  
David Johnston ◽  
Hans Graser

The advantages of using a univariate threshold animal model (TAM) over the conventional linear animal model (AM) in the development of a genetic evaluation system for feet and leg traits of Angus cattle were explored. The traits were scored on a scale of 1–9 with scores 5 and 6 being the most desirable. The genetic parameters and estimated breeding values for front feet angle (FA), rear feet angle (RA), front feet claw set (FC), rear feet claw set (RC), rear leg hind view (RH) and rear leg side view (RS) were compared from AM and TAM. In order to predict breeding values to identify the animals with intermediate optimum, the scores were categorised to form three groups to differentiate the desirable group (5–6) from the other two groups with less desirable feet and leg appearances (1–4 and 7–9). The AM and TAM were used to estimate genetic parameters for the grouped data as well as the original score data. A TAM using the group data was used to predict the probability and breeding value for the desirable intermediate group. For the original score data, estimated heritabilities on the underlying scale, using TAM, were 0.50, 0.46, 0.35, 0.44, 0.32 and 0.22 for FA, FC, RA, RC, RH and RS, respectively, and were 0.01–0.18 higher than the heritabilities estimated using AM. Genetic correlation between the six traits using a bivariate TAM with all scores ranged from 0.02 to 0.50 with front and rear angles had the highest genetic correlation at 0.50. For all six traits, proportion in the intermediate desirable group was higher than the other two groups combined. The low annual genetic change observed for all six traits over the 10 years of data recording reflected the lack of directional selection to improve the traits in Angus cattle. For genetic evaluation of feet and leg traits with an intermediate optimum, TAM is a preferred method for estimating genetic parameters and predicting breeding values for the desirable category. The TAM has now been implemented for regular estimated breeding value analysis of feet and leg traits of Angus cattle.


Author(s):  
K Devani ◽  
J J Crowley ◽  
G Plastow ◽  
K Orsel ◽  
T S Valente

Abstract Poor teat and udder structure, frequently associated with older cows, impact cow production and health, as well as calf morbidity and mortality. However, producer culling, for reasons including age, production, feed availability, and beef markets, creates a bias in teat and udder scores assessed and submitted to the Canadian Angus Association for genetic evaluations towards improved mammary structure. In addition, due to the infancy of the reporting program, repeated scores are rare. Prior to adoption of genetic evaluations for teat and udder scores in Canadian Angus cattle, it is imperative to verify that teat and udder scores from young cows are the same trait as teat and udder scores estimated on mature cows. Genetic parameters for teat and udder scores from all cows (n=4,192), and then from young cows (parity 1 and 2) and from mature cows (parity ≥ 4) were estimated using a single trait animal model. Genetic correlations for the traits between the two cow age groups were estimated using a two-trait animal model. Estimates of heritability (PSD) were 0.32 (0.07) and 0.45 (0.07) for young teat and udder score, and 0.27 (0.07) and 0.31 (0.07) for mature teat and udder score, respectively. Genetic correlation (PSD) between the young and mature traits was 0.87 (0.13) for teat score and 0.40 (0.17) for udder score. GWAS were used to further explore the genetic and biological commonalities and differences between the two groups. Although there were no genes in common for the two udder scores, 12 genes overlapped for teat score in the two cow age groups. Interestingly, there were also 23 genes in common between teat and udder scores in mature cows. Based on these findings, it is recommended that producers collect teat and udder score on their cow herd annually.


2016 ◽  
Vol 32 (3) ◽  
pp. 261-269 ◽  
Author(s):  
Dragomir Lukac ◽  
Vitomir Vidovic ◽  
Teodora Vasiljevic ◽  
Oliver Stankovic

The aim of this study was to estimate the genetic parameters and breeding values for reproduction traits of Landrace sows in the first three parities by Animal model. Records of 2238 first parity; 2125 second parity and 1872 third parity Landrace sows farrowing between 2007 and 2012 were included in the analysis. The traits included in the analyses were total pigs born (TB), number of pigs born alive (NBA), number of pigs weaned (NW) and litter weaning weight (LW) in the parities. The genetic parameters were estimated using a multivariate analyses Animal model using REML procedure. Estimates of heritability for TB were 0.03, 0.05 and 0.18, for NBA were 0.04, 0.02 and 0.17, for NW were 0.08, 0.08 and 0.01 and for LW were 0.09, 0.11 and 0.03 for parities 1 to 3. Genetic and phenotypic variance were increased from the first to the third parity. Between the majorities of studied reproductive traits were the recorded positive genetic and phenotypic correlations, except between LW and other analyzed properties where they recorded a high correlation negative in third parity. Means of estimated breeding values of reproductive traits from first parity to third parity was indecreased.


2021 ◽  
Author(s):  
Antonio Reverter ◽  
Brad C. Hine ◽  
Laercio Porto-Neto ◽  
Pamela A. Alexandre ◽  
Yutao Li ◽  
...  

2005 ◽  
Vol 48 (4) ◽  
pp. 404-411
Author(s):  
N. Mielenz ◽  
M. Schmutz ◽  
L. Schüler

Abstract. Title of the paper: Mortality of laying hens housed in single and group cages This study provides genetic parameters for mortality of laying hens estimated with linear and threshold models. Records of one line from a commercial breeding programme of White Leghorns from three generations were available. Data included observations of 8636 hens from single and from 6908 hens of group cages. Mortality was defined as death in the first six months of lay with dead=1 and alive=0. The average mortality was 3.3% in single and 6.3% in group cages. The binary traits were analysed separately by linear animal (LAM), by threshold animal (TAM) and by threshold sire models. Further the two mortalities were analysed together by a linear-linear animal (LLAM) and threshold-threshold animal model (TTAM). The LLAM estimates of heritability were 1.5% for single and 3.2% for group cages. The heritability estimates of TTAM ranged from 9.6% to 9.9%. The rank correlations between breeding values of LAM and TAM were for all sires, the 10% best and the 5% best sires in the range 0.96 to 1.00. The analysis of rank correlations of the linear and threshold models showed: The LLAM provides a good (but only suboptimal) alternative for breeding value estimation of mortality in the investigated laying hen population.


FLORESTA ◽  
2020 ◽  
Vol 50 (2) ◽  
pp. 1267 ◽  
Author(s):  
Rodrigo Andrade Furlan ◽  
Evandro Vagner Tambarussi ◽  
Cristiano Bueno Moraes

Brazil is the largest charcoal producers in the world, with the main centers of charcoal consumption located in the states of Minas Gerais, Mato Grosso do Sul, Espírito Santo, Maranhão, and Pará. Planting of Eucalyptus in the northern and northeastern states of Brazil is relatively new and is limited the lack of genetic materials adapted to the region’s high temperatures and severe, prolonged periods of drought. The objective of this study was to assess the genetic parameters and variability and determine the genotype x environment interaction for drought tolerance in Eucalyptus clonal tests established in two environments in the municipality of Grajaú, Maranhão State, Brazil. The tests were planted in January 2011 in clayey and sandy soils in a randomized complete block design with 130 clones, one plant per plot, and 20 replicates. The studied clones showed high genetic variability for drought tolerance, with coefficients of relative variance () consistently greater than 0.8 for DBH and volume. This indicates high levels of genetic control and less influence of environmental factors on the phenotype, which allows for selection and obtaining gains through breeding. Heritability estimates were high for growth traits, with average clone heritabilities () greater than 0.85, as well as acuracies () above 0.9 for DBH and volume in clone selection. There was a simple interaction between genotype x environment for the clones under the two different soil conditions.


Author(s):  
Caio Victor Damasceno Carvalho ◽  
Raphael Bermal Costa ◽  
Gregório Miguel Ferreira de Camargo ◽  
Thereza Cristina Calmon Bittencourt

SUMMARY The objective of this study was to evaluate the effect of the genotype-environment interaction (GEI) for scrotal circumference traits measured at different ages, 365 (SC365), 450 (SC450) and 550 (SC550) days of age, and age at first calving (AFC) for Nellore animals raised in different regions of Brazil. For the evaluation, the herds were grouped in the following regions of the country: North, Southeast and Central-west, using information from 26,619, 28,730, 14,476, 15,397 for the traits SC365, SC450, SC550 and AFC respectively. Genetic parameters, as well as the assessment of GEI were performed using Bayesian inference, using the programs of the BLUPF90. The estimated heritabilities were: 0.465 ± 0.021, 0.500 ± 0.022, 0.492 ± 0.026, 0.117 ± 0.017 for SC365, SC450, SC550 and AFC respectively. The results obtained in the analysis, indicated that this interaction was not significant for SC at different ages (genetic correlation, rg> 0.8). For AFC, significant effect of GEI was observed for combinations involving the Northern region (rg<0.8), indicating that this interaction should be considered by the genetic evaluation programs in this region.


2018 ◽  
Vol 19 (4) ◽  
pp. 403-414
Author(s):  
Rúbia Francielle Moreira Rodrigues ◽  
Mariele Freitas Sousa ◽  
Valdecy Aparecida Rocha Cruz ◽  
Thaiza da Silva Campideli ◽  
Leonardo da Silva Costa ◽  
...  

SUMMARY We aimed to evaluate the random regression models that promote the best fit of residual variance predicting the breeding values of quail body weights and the sensitivity of its breeding values to the variations of different tryptophan:lysine ratios in the diets via reaction norms. A total of 1112 meat quails from LF1 and LF2 lines with 35 days of age were evaluated. During the period of 1 to 21 days of age, birds were fed with different tryptophan:lysine ratios (0.17, 0.20, 0.23, 0.26 and 0.29%) containing 2900 kcal ME/kg and 26.10% crude protein, followed by basal diet provided up to 35 days. The best model fit for residual variance was evaluated comparing heterogeneity (2, 3 and 4 classes) and homogeneity (1 class), including sex as fixed effect and the additive genetic effect as random. The second order Legendre polynomial was used to analyze the genotype x environment interaction using reaction norms. The model considering two classes of residual variance was the one that promoted the best fit of the data, being adopted to predict the breeding values. Thus, we observed changes in the sensitivity of the breeding values, characterized by the rearrangement of the breeding values, according to the different ratios of amino acids, suggesting the genotype x environment interaction.


2013 ◽  
Vol 8 (38) ◽  
pp. 4853-4859 ◽  
Author(s):  
Rafael Delmond Bueno ◽  
◽  
Leandro Luiz Borges ◽  
Klever Márcio Antunes Arruda ◽  
Leonardo Lopes Bhering ◽  
...  

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