Estimation models of variance components for farrowing interval in swine

Neto, Aderson Costa Araujo; Lui, Jeffrey Frederico; Sarmento, José Lindenberg Rocha; Ribeiro, Maria Norma; Monteiro, John M.; Fonseca, Carlos; Tonhati, Humberto

doi:10.1590/s1516-89132009000100009

Cited by 11 publications

(14 citation statements)

References 32 publications

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“…The heritabilities for FI across breeds and connectedness groups were low (ranged from 0.01 to 0.03), and this agrees with the report from previous studies (Akanno et al, ; Cavalcante Neto et al, ). Serenius et al (), using repeatability models for Finnish Landrace and Large White populations, obtained calculated heritability that varied from 0.04 to 0.16 for FI.…”

Section: Discussionsupporting

confidence: 91%

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Estimation of genetic parameters for reproductive traits in connectedness groups of Duroc, Landrace and Yorkshire pigs in China

Zhang

Olasege

et al. 2019

J Animal Breeding Genetics

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The objective of this study was to estimate group‐ and breed‐specific genetic parameters for reproductive traits in Chinese Duroc, Landrace, and Yorkshire populations. Records for reproductive traits between April 1998 and December 2017 from 92 nucleus pig breeding farms, which were involved in the China Swine Genetic Improvement Program, were analysed. Due to weak genetic connectedness across all farms, connectedness groups consisting of related farms were used. Three, two and four connectedness groups for Duroc, Landrace and Yorkshire were firstly established according to the genetic connectedness rating among farms. For each connectedness group a five‐trait animal model was implemented, and via restricted maximum likelihood procedure the genetic parameters were estimated for five reproductive traits i.e., total number born (TNB), number born alive (NBA), litter weight at farrowing (LWF), farrowing interval (FI) and age at first farrowing (AFF). The average of heritabilities among connectedness groups ranged from .01 (for FI in Yorkshire) to .30 (for AFF in Duroc). Estimates of repeatability for litter traits ranged from .14 to .20 and were consistent for each breed, and for FI, the estimates varied from .01 to .11 across breeds and groups. The estimated genetic correlations among litter traits (i.e., TNB, NBA and LWF) were all significantly high (>.56) and similar across breeds. Averaged genetic correlations over three breeds were −.25, −.27, −.18, −.04, −.10, −.02, and .28 for FI‐TNB, FI‐NBA, FI‐LWF, AFF‐TNB, AFF‐NBA, AFF‐LWF and FI‐AFF, respectively. The standard errors of the estimates were all very low (<0.01) in most situations. Results from this study suggest that selection based on TNB which is currently used in dam line selection index can improve NBA and LWF simultaneously. However, care should be taken on FI and AFF as they are both greatly influenced by non‐genetic factors such as management and measurement.

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Section: Discussionsupporting

confidence: 91%

“…The estimated repeatability for litter traits were in agreement with previous studies (Chen et al, ; Crump et al, ) and the repeatability estimates for FI obtained were similar with the report of (Cavalcante Neto et al, ), who reported an estimates ranging from 0.05 to 0.07 in a Brazil pig population.…”

Section: Discussionsupporting

confidence: 91%

Estimation of genetic parameters for reproductive traits in connectedness groups of Duroc, Landrace and Yorkshire pigs in China

Zhang

Olasege

et al. 2019

J Animal Breeding Genetics

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“…Knowledge of the influence of environmental and genetic factors on these traits is becoming increasingly important (Cavalcante-Neto et al, 2009a;Leite et al, 2011), considering the geographic dimensions of Brazil, with regions of different climates, not to mention deficient management, inadequate facilities, and animals that are not always of high breeding value (Pinheiro et al, 2000;Cavalcante-Neto et al, 2008a, 2009b.…”

Section: Introductionmentioning

confidence: 99%

Genetic and environmental effects on age at first farrowing in sows in southeastern Brazil

Cavalcante-Neto¹,

Lui²,

Sarmento³

et al. 2011

Genet. Mol. Res.

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ABSTRACT. We evaluated genetic and environmental factors affecting age at first farrowing of sows in the Brazilian southeast. For this purpose, 466 observations regarding the age at first farrowing were made for Dalland-C40 © animals belonging to two herds. The effects of the environmental factors on this trait were assessed by means of a model that included, as random effects, the influence of the sow's father and mother and, as fixed effects, the influence the year of birth, the herd and the birth season, along with the covariable litter size at birth. The variance components were estimated using the derivative-free restricted maximum likelihood method. The estimated mean was 354.8 ± 25.87 days, with a coefficient of variation of 7.29%. Significant effects on the trait were observed for the herd, the year and the season of birth; Genetic and environment effects on age at first farrowing but a linear effect of litter size at birth on the age at first farrowing was not observed. The boar did not significantly contribute to the variation occurring among the sows, whereas the sow's mother caused significant variation. The heritability estimate for the age at first farrowing was 0.44 ± 0.15, which is considered high. We concluded that herd effect and year and season of birth should be taken into consideration for an accurate genetic comparison; consequently, the animals should be joined into contemporary groups.

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“…Esse ambiente comum afeta o desempenho dos animais em toda a sua vida e é determinado, principalmente, pela matriz, através dos seus cuidados com a cria, sua produção de leite etc. (CAVALCANTE-NETO et al, 2009;TORRES FILHO et al, 2005).…”

Section: Os Valores De Aic E Bic Também Apontaram O Modelo 1 Como O Qunclassified

“…Atualmente, em suínos, diversos trabalhos têm utilizado o efeito comum-de-leitegada nos modelos para estimação de componentes de variância, inclusive em características que se manifestam tardiamente na vida da fêmea suína, como as reprodutivas (CAVALCANTE-NETO et al, 2008, 2009CHIMONYO et al, 2006;KAUFMANN et al, 2000;LUKOVIC et al, 2003LUKOVIC et al, , 2004LUKOVIC et al, , 2007.…”

Section: Os Valores De Aic E Bic Também Apontaram O Modelo 1 Como O Qunclassified

Modelos de regressão aleatória com diferentes estruturas de variância residual para descrever o tamanho da leitegada

Cavalcante-Neto¹,

Tholon²,

Lui³

et al. 2011

Rev. Ciênc. Agron.

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Resumo -Objetivou-se comparar modelos de regressão aleatória com diferentes estruturas de variância residual, a fim de se buscar a melhor modelagem para a característica tamanho da leitegada ao nascer (TLN). Utilizaram-se 1.701 registros de TLN, que foram analisados por meio de modelo animal, unicaracterística, de regressão aleatória. As regressões fixa e aleatórias foram representadas por funções contínuas sobre a ordem de parto, ajustadas por polinômios ortogonais de Legendre de ordem 3. Para averiguar a melhor modelagem para a variância residual, considerou-se a heterogeneidade de variância por meio de 1 a 7 classes de variância residual. O modelo geral de análise incluiu grupo de contemporâneo como efeito fixo; os coeficientes de regressão fixa para modelar a trajetória média da população; os coeficientes de regressão aleatória do efeito genético aditivo-direto, do comumde-leitegada e do de ambiente permanente de animal; e o efeito aleatório residual. O teste da razão de verossimilhança, o critério de informação de Akaike e o critério de informação bayesiano de Schwarz apontaram o modelo que considerou homogeneidade de variância como o que proporcionou melhor ajuste aos dados utilizados. As herdabilidades obtidas foram próximas a zero (0,002 a 0,006). O efeito de ambiente permanente foi crescente da 1 a (0,06) à 5 a (0,28) ordem, mas decrescente desse ponto até a 7 a ordem (0,18). O comum-de-leitegada apresentou valores baixos (0,01 a 0,02). A utilização de homogeneidade de variância residual foi mais adequada para modelar as variâncias associadas à característica tamanho da leitegada ao nascer nesse conjunto de dado. Palavras-chave -Função de covariância. Parâmetro genético. Fêmea suína.Abstract -The objective of this work was to compare random regression models with different residual variance structures, so as to obtain the best modeling for the trait litter size at birth (LSB) in swine. One thousand, seven hundred and one records of LSB were analyzed. LSB was analyzed by means of a random-regression, single-characteristic animal model. The fixed and random regressions were represented by continuous functions over the farrowing order, adjusted by third-order Legendre's orthogonal polynomials. To obtain the best modeling for the residual variance, variance heterogeneity was assumed by means of 1 to 7 classes of residual variance. The general analysis model included a contemporary group; the fixed regression coefficients for modeling the population's average trajectory; the random regression coefficients of the direct additive genetic effects both of the litter and of the animal's permanent environment; and the residual random effect. The likelihood-ratio test, Akaike's information criterion, and Schwarz's Bayesian information criterion appointed the model that considered variance homogeneity as being the one that provided the best adjustment to the data used. Overall, the heritabilities obtained were close to zero (0.002 to 0.006). Regarding the permanent environment proportion, different magnitudes were o...

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Estimation models of variance components for farrowing interval in swine

Cited by 11 publications

References 32 publications

Estimation of genetic parameters for reproductive traits in connectedness groups of Duroc, Landrace and Yorkshire pigs in China

Estimation of genetic parameters for reproductive traits in connectedness groups of Duroc, Landrace and Yorkshire pigs in China

Genetic and environmental effects on age at first farrowing in sows in southeastern Brazil

Modelos de regressão aleatória com diferentes estruturas de variância residual para descrever o tamanho da leitegada

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