Genetic Parameters for Gestation Length, Birth Date and First Breeding Date in Beef Cattle

Azzam, Sara Melin; Nielsen, Marie Vejrup

doi:10.2527/jas1987.642348x

Cited by 37 publications

(26 citation statements)

References 5 publications

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“…The direct heritability estimate of 0.18 for CD1 corresponds with the pooled estimate of 0.17 (Meacham and Notter 1987), which is larger than values reported (≤ 0.09) in other studies (Azzam and Nielsen 1987;Smith et al 1989;Johnston and Bunter 1996). In the Canadian Angus cattle of the Prairies, there appears to be sufficient additive genetic variation for genetic improvement of CD1 (increased frequency of early calving in the calving season) and juvenile growth traits.…”

Section: Heritabilitiescontrasting

confidence: 38%

“…Literature estimates for CD with slightly varying definitions include 0.17 ± 0.03 for cows in the second parity and 0.24 ± 0.06 in the third parity (Azzam and Nielsen 1987), 0.36 ± 18 in the second parity (Smith et al 1989), 0.20 ± 0.16 and 0.39 ± 0.21 in the first parity for two data sets of Hereford cattle that had lower estimates in the subsequent parities (Buddenberg et al 1990). In contrast, a number of studies reported estimates lower than 0.10 (Meyer et al 1991;Burrow 2001), which may support the conventional notion that reproductive traits are lowly heritable.…”

Section: Heritabilitiesmentioning

confidence: 99%

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Multiple trait estimates of genetic parameters for juvenile growth and calving traits in Canadian Angus cattle

Rasali¹,

Crow²,

Shrestha³

et al. 2005

Can. J. Anim. Sci.

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. 2005. Multiple trait estimates of genetic parameters for juvenile growth and calving traits in Canadian Angus cattle. Can. J. Anim. Sci. 85: 309-316. Two analyses, both with three calf body weights at birth (BW), weaning (WW) and yearling (YW), one including first calving date (CD1) using a fourtrait model, and the other including calving date (CD) and interval (CI) in a five-trait model, were carried out for a pooled population of beef cattle from one herd in Manitoba (n = 3,601), three herds in Alberta (n = 779, 600 and 967) and one herd in Saskatchewan (n = 495) totaling 6442 calving records for years 1984 through 2001.Multiple-trait mixed-animal model methodology was utilized in both analyses to estimate genetic parameter estimates for three juvenile growth traits with three calving traits. The direct heritability estimates for BW, WW and YW from Analyses (1, 2) were (0.51, 0.45), (0.70, 0.70) and (0.52, 0.79), respectively, and corresponding maternal heritability estimates were (0.10, 0.18), (0.20, 0.24) and (0.06, 0.12), respectively. Estimates of direct heritabilities for CD1 (Analysis 1), CD (Analysis 2) and CI (Analysis 2) were 0.18, 0.25 and 0.10, respectively. Estimates of genetic correlations among direct effects on juvenile growth traits ranged from 0.31 to 0.89, and those among maternal genetic effects ranged from 0.20 to 0.98. Estimates of direct-maternal genetic correlations within each of BW, WW and YW ranged from -0.61 to -0.06, but those between any two growth traits were variable, with positive genetic correlations shown particularly between maternal BW with direct WW and direct YW. Direct genetic correlation estimates of BW, WW and YW with CD1 were -0.01, 0.28 and 0.04, respectively. Correspondingly, estimates of genetic correlations of maternal BW, WW and YW with direct CD1 were 0.02, -0.73 and -0.75, respectively. Estimates of direct genetic correlations of BW, WW and YW with CD were -0.19, -0.31 and -0.21, respectively, and those with CI were -0.29, -0.38 and -0.65, respectively. Correspondingly, estimates of genetic correlations maternal BW, WW and YW between direct CD (CI) were -0.02 (0.00), -0.18 (0.07) and -0.36 (0.51), respectively. The genetic trends for direct BW, WW and YW were 0.167, 1.817 and 4.394 kg yr -1 , respectively, and those for direct CD and CI were -1.089 and -0.088 d yr -1 , respectively, and for maternal BW, WW and YW were -0.015, -0.065 and -0.952 kg yr -1 , respectively. The genetic parameter estimates indicate potential merit for developing breeding strategies that permit genetic improvement of both growth and dams' calving efficiency in Canadian Angus cattle. 309Abbreviations: BOA, Bayesian output analysis; BW, birth weight; CD1, first calving date; CD, calving date; CI, calving interval; EBV, estimated breeding value; MTDFREML, multiple-trait derivative-free restricted maximum likelihood; MTGSAM, multiple-trait Gibbs sampling animal model; n, number of animals; r TI , accuracy of breeding value prediction; WW, weaning weight; YW, yearling weight Can. J. Anim....

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Section: Heritabilitiescontrasting

confidence: 38%

Section: Heritabilitiesmentioning

confidence: 99%

Multiple trait estimates of genetic parameters for juvenile growth and calving traits in Canadian Angus cattle

Rasali¹,

Crow²,

Shrestha³

et al. 2005

Can. J. Anim. Sci.

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show abstract

“…There are no available papers using animal model to estimate genetic parameters of gestation length. Usually, genetic parameters of gestation length have been calculated under a sire or sire-maternal grand sire model (AZZAM and NIELSEN, 1987;NADARAJAH et al, 1989) assuming a non zero covariance between direct and maternal genetic effects. These modeis could lead to an overestimation of direct and maternal genetic variance if covariance is moderate to high and negative (MEYER, 1994).…”

Section: Methodsmentioning

confidence: 99%

Heritability of reproduetive traits in Asturiana de los Valles beef cattle breed

Gutiérrez

2001

Arch. Anim. Breed.

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SummaryHeritability was estimated for four reproduetive traits in the Asturiana de los Valles breed in order to evaluate the possibility of include this information in the breed's current improvement program. The estimations were done using an animal model except for calving ease score. For this last trait, a threshold model under a sire model was fitted, with the sire effect as the only random effect in the model besides the residual. Estimated heritabilities for calving interval age at first calving, gestation length, as dam traits, and calving ease were 0.12, 0.27, 0.15 and 0.42, respectively. The estimated heritability for calving interval and age at first calving could justify a sire selection program in the Asturiana de los Valles breed taking account their female offsprings' reproduetive characteristics. Heritability estimates for gestation length and calving ease suggested a close genetic relationship of these two traits and birth weight. Further research is needed to estimate the genetic (co)variances between these three traits to allow the use of this information in a breed improvement program to reduce dystocia without affecting preweaning growth traits.

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“…Mercadante (2001) avaliou rebanhos Nelore que passaram ou não por seleção e encontrou valores de herdabilidade de 0,02 a 0,16. Estimativas de herdabilidade para data juliana do parto, característica equivalente, variam de 0,02 a 0,17 (Azzam & Nielsen, 1987;Meacham & Notter, 1987;Reget & Famula, 1993;Gressler et al, 2000).…”

Section: Resultsunclassified

Avaliação de fatores de ambiente e estimativas de parâmetros genéticos para a característica dias para o parto na raça Nelore

Forni

Albuquerque

2006

R. Bras. Zootec.

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RESUMO -Dados de um rebanho comercial da raça Nelore foram analisados com os objetivos de avaliar a influência de fatores ambientais e estimar parâmetros genéticos para a característica dias para o parto (DPP). Foram utilizados modelos fixos que incluíram os efeitos de grupo de contemporâneos, sexo do bezerro, idade da vaca no início da estação de monta, mês do parto anterior e peso do bezerro desmamado no final da estação de monta (apenas este último efeito não influenciou a característica significativamente). Duas definições de grupo de contemporâneos foram consideradas: a primeira definida pelas informações fazenda, ano e estação de monta, grupos de manejo (nascimento, desmama e reprodução) e tipo de serviço (monta natural, monta controlada ou inseminação artificial); e a segunda, pelas mesmas informações mais o sexo do bezerro. As análises genéticas foram realizadas com conjuntos de dados que incluíram ou não os animais sem registros de parto. Quando incluídos, o valor de DPP atribuído a esses animais foi igual ao maior valor observado dentro do grupo de manejo somado a 21 dias. Os componentes de variância foram estimados por máxima verossimilhança restrita utilizando-se modelos animal unicaracterística. A inclusão do efeito aleatório de ambiente permanente nos modelos foi avaliada mediante o "Likelihood Ratio Test". As herdabilidades estimadas variaram entre 0,01 e 0,11 e a inclusão do efeito de ambiente permanente nos modelos foi significativa, de modo que a exclusão deste efeito superestimou a variância genética aditiva. A metodologia aplicada para penalizar os animais que não pariram não melhorou a identificação das diferenças genéticas entre eles. Os resultados indicaram que, como grande parte das características reprodutivas em bovinos, a DPP sofre grande influência do ambiente.Palavras-chave: características reprodutivas, efeitos ambientais, gado de corte, parâmetros genéticos Environmental effects and genetic parameters estimates for days to calving in Nelore cattleABSTRACT -Data from a Nelore population was used to evaluate environmental effects and to estimate genetic parameters for days to calving (DPP). The influence of contemporary group, age at breeding season, month of last calving and weaning weight of the calf at the end of the breeding season were evaluated with fixed models. The weaning weight of the calf at the end of the breeding season was the only effect that did not influence DPP. Two different contemporary group (CG) definitions were also evaluated. Herd, year and season of breeding, management groups (birth, weaning and breeding) and mating type (multiple sires, single sire or artificial insemination) defined the first CG and the second CG included the same variables and sex of the calf. Variance components were estimated using restricted maximum likelihood method fitting univariate animal models, including or not non-calvers cows (which were penalized by adding 21 days to the largest DPP record in their management group). Heritability estimates ranged between 0.01 and 0.11. Exclusi...

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Genetic Parameters for Gestation Length, Birth Date and First Breeding Date in Beef Cattle

Cited by 37 publications

References 5 publications

Multiple trait estimates of genetic parameters for juvenile growth and calving traits in Canadian Angus cattle

Multiple trait estimates of genetic parameters for juvenile growth and calving traits in Canadian Angus cattle

Heritability of reproduetive traits in Asturiana de los Valles beef cattle breed

Avaliação de fatores de ambiente e estimativas de parâmetros genéticos para a característica dias para o parto na raça Nelore

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