Contribuição dos efeitos de genearcas e de famílias sobre a probabilidade de permanência em rebanhos da raça Nelore

Marcondes, C. R.; Vozzi, Pedro Alejandro; Araújo, Ronyere Olegário de; Gloria, Wíris Pereira; Lôbo, Raysildo Barbosa

doi:10.1590/s0102-09352007000400025

Cited by 6 publications

(4 citation statements)

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“…This has been evidenced in various genetic structure population studies involving a number of breeds in Brazil (Marcondes et al, 2007;Oliveira et al, 2011) and indicates the need to consider GEI in genetic evaluations, to select animals to be used in herds under different production systems. Corrêa et al (2010) obtained estimates of Spearman's correlations higher than those in the present study, with values of 0.12 to 0.98 for 5% of the best sires and higher for 10% of the sires, with values of 0.75 to 0.99 for post-weaning gain standardized at 365 days.…”

Section: Resultsmentioning

confidence: 99%

Reaction norms models in the adjusted weight at 550 days of age for Polled Nellore cattle in Northeast Brazil

et al. 2014

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-The objective of this study was to evaluate the genotype-environment interaction (GEI) in the body weight adjusted to 550 days of age (W550) of Polled Nellore cattle raised in Northeastern Brazil using reaction norms (RN) models. Hierarchical RN models included fixed effects for age of cow (linear and quadratic) and random effects for contemporary groups (CG) and additive genetic RN level and slope. Four RN hierarchical models (RNHM) were used. The RNHM 2S uses the solutions of contemporary groups estimated by the standard animal model (AM) and considers them as environmental level for predicting the reaction norms and the RNHM 1S , which jointly estimate these two sets of unknowns. Two versions were considered for both models, one with a homogeneous (Hm) and another with a heterogeneous (He) residual variance. The one-step homogeneous residual variance model (RNHM 1S Hm) offered better adjustment to the data when compared with other models. For the RNHM 1S Hm model, estimates of additive genetic variance and heritability increased with environment improvement (260.75±75.80 kg 2 to 4298.39±356.56 kg 2 and 0.22±0.05 to 0.82±0.01, for low-and high-performance environments, respectively). High correlation (0.97±0.01) between the intercept and the slope of RN shows that animals with higher genetic values respond better to environment improvement. In the evaluation of breeding sires with higher genetic values in the various environments using Spearman's correlation, values between 0 and 0.98 were observed, pointing to high reclassification, especially among genetic values obtained by the animal model in comparison with those obtained via RNHM 1S Hm. The existence of GEI is confirmed, and so is the need for specific evaluations for low, medium and high level production environments.

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Section: Resultsmentioning

confidence: 99%

Reaction norms models in the adjusted weight at 550 days of age for Polled Nellore cattle in Northeast Brazil

et al. 2014

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“…1 (Faria et al, 2001) e Tabapuã e para a raça Sahiwal australiana (Herron, 1978), os quais foram acima de seis anos. Malhado et al (2008) obtiveram os seguintes resultados para a raça Mediterrâneo: 11,2±3,7 (pai-filho), 12,1±3,9 (pai-filha), 9,6±4,8 (mãe-filho) e 10,6±4,6 (mãe-filha). Além dos argumentos utilizados pelos autores quanto ao longo período entre gerações, como a longa vida produtiva e a necessidade de crescimento do rebanho, os valores refletiriam, também, a baixa oferta de touros melhoradores e o pouco estímulo ao uso de touros jovens, o que levaria ao incremento do ganho genético intrarrebanho, e aos programas de melhoramento, ainda incipientes, no país.…”

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“…Um estudo como este permitirá que sejam relacionadas características produtivas dos ancestrais e seus descendentes. Marcondes et al (2007) observaram que, dentre os touros melhor classificados quanto à característica stayability, dos sete ancestrais que aportaram o maior percentual de genes, cinco eram da variedade mocha. Outra aplicação é a identificação de linhas para direcionamento da seleção de pais de touros ou mães de touros, como relatado por Magnabosco et al (1997) sobre a utilização do acasalamento em linha na formação de diferentes linhagens na raça Nelore.…”

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Variabilidade genética de búfalos em rebanho-núcleo com base na análise de pedigree

Marcondes

Vozzi²,

Cunha

et al. 2010

Arq. Bras. Med. Vet. Zootec.

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RESUMOParâmetros baseados na probabilidade de origem do gene foram usados para descrever a variabilidade em uma população de búfalos da Embrapa Amazônia Oriental. A magnitude dos resultados foi de média a baixa (por volta de 20 animais), sugerindo que poucos fundadores contribuiriam para a formação da população. Dentre os 20 ancestrais que mais aportam genes aos machos -representando ao todo 71% dos alelos -, 39%, 26% e 5%, respectivamente, são as contribuições marginais das raças Murrah e Mediterrâneo e seus mestiços. Para as fêmeas, em que os 20 ancestrais aportam 67,5% dos genes, 42% e 26%, respectivamente, são as contribuições marginais das raças Murrah e Mediterrâneo. Palavras-chave: Bubalus bubalis, contribuição marginal, estratégia de acasalamento, estrutura da população ABSTRACT Parameters based on the probability of gene origin were used to describe genetic variability in a buffalo

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“…Furthermore, Nellore-sired cows have been shown to maintain udder integrity and to have increased survivability and overall lifetime productivity than other B. indicus-or B. taurus-sired females (Riley et al, 2001). In a Brazilian study estimating the influence of popular Nellore founders on the current top 1% of Nellore sires for stayability EPD, the bull Karvadi was the most influential bull and contributed an estimated 8.2% of the genetics in the population subset, mainly through his son Chummak (Marcondes et al, 2007). Karvadi is the great great grand-sire of two of the F 1 donor cows through his son Chummak, and an F 1 bull that contributed to four ET families and an NS family through his son Chakkar.…”

Section: Figurementioning

confidence: 99%

Genome-wide association study for stayability measures in Nellore–Angus crossbred cows1

Engle

Herring

Sawyer

et al. 2018

Journal of Animal Science

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Beef cow stayability is a complex, economically important trait often used as an indicator of a cow's potential lifetime productivity. Stayability is defined as capability of a cow to maintain a perfect record up to 6 yr of age. This age is commonly cited as a financial break-even point, where initial costs of cow development and maintenance are recovered by her cumulative net income from yearly calf receipts. Later-maturing Bos indicus-Bos taurus crossbred cows may experience reproductive difficulty early in life but have a high potential for a long reproductive life span. It was the objective of this study to identify genetic variants associated with measures of beef cow stayability. A population of B. indicus-B. taurus crossbred cows (n = 305) from central Texas was used. Phenotypes for various measures of stayability to 6 yr of age were produced by artificially imposing five different culling criteria on data from the population. Cows were scored either as a 1 (indicating a perfect record through 6 yr) or a 0 (indicating failure at or before 6 yr), under each criterion. Genome-wide association studies (GWAS) were conducted for each criterion using univariate procedures and prefitting the fixed effect of cow contemporary group. SNP associations for two criteria surpassed the false discovery threshold of 0.15, when a cow was scored as 0 upon her first failure to wean a calf, regardless of reason, through 6 yr (criterion 2), and when a cow was scored as 0 upon her first failure to give birth to a calf, through 6 yr (criterion 3). Associated SNP were found on bovine chromosomes (BTA) 1, 2, 5, 9, 18, and 21 for criterion 2 and on BTA 1, 5, 11, 15, and 24 for criterion 3. A critical region on BTA 5: 43-50 Mb was identified for each criterion. Due to the similarities to prior work, the tendency for B. indicus cattle to experience reproductive difficulties early in life, and due to the large proportion of cows that left the herd at an early age under these criteria, these results suggest that the associations are likely driven by an early life trait such as age at puberty or rate of heifer development.

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Contribuição dos efeitos de genearcas e de famílias sobre a probabilidade de permanência em rebanhos da raça Nelore

Cited by 6 publications

References 5 publications

Reaction norms models in the adjusted weight at 550 days of age for Polled Nellore cattle in Northeast Brazil

Reaction norms models in the adjusted weight at 550 days of age for Polled Nellore cattle in Northeast Brazil

Variabilidade genética de búfalos em rebanho-núcleo com base na análise de pedigree

Genome-wide association study for stayability measures in Nellore–Angus crossbred cows1

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