Comparison among three approaches for evaluation of sexual precocity in Nellore cattle

Pereira, Eric; Oliveira, Henrique Nunes de; Eler, Joanir Pereira; Silva, Josineudson Augusto Ii Vasconcelos; Melis, M. H. Van

doi:10.1017/s1751731107392732

Cited by 11 publications

(11 citation statements)

References 16 publications

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“…The heritability estimate of 0.53 ± 0.03 obtained in this study for HP on the liability scale indicates the importance of genetic variance for this trait as well. Similar heritability values in Nellore cattle (0.57 ± 0.11, 0.61 ± 0.10, and 0.58 ± 0.13) were reported by Eler et al (2002Eler et al ( , 2004 and Pereira et al (2007), respectively. Pereira et al (2006), using survival analysis for Nellore cattle, estimated a value of 0.51 for heritability, on the logarithmic scale, of age at first conception for females exposed to sires for the first time at about 14 mo of age.…”

Section: Estimates Of Heritabilitiessupporting

confidence: 79%

“…On average, puberty in Nellore breed (Bos indicus) is expressed at a later age, and the genetic variability of HP seems to be much greater (Eler et al, 2004). Eler et al (2004) and Pereira et al (2007) suggested the use of HP as a selection criterion, with the aim of indicating early puberty in the Nellore breed.…”

Section: Estimates Of Heritabilitiesmentioning

confidence: 99%

“…The only exception is the scrotal circumference (SC), included in the indexes as an indicator trait for age to puberty and fertility. More recently, however, some authors have evaluated economically relevant traits that can be measured directly on females, such as heifer pregnancy (HP;Evans et al, 1999;Eler et al, 2002Eler et al, , 2004Silva et al, 2003;Pereira et al, 2007) and stayability (STAY;Snelling et al, 1995;Doyle et al, 2000;Silva et al, 2003Silva et al, , 2006Van Melis et al, 2007). Heifer pregnancy and STAY traits have several properties that confirm them as candidates for inclusion in selection objectives; first, recording HP data presents no additional costs because they are routinely collected by producers.…”

Section: Introductionmentioning

confidence: 99%

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Additive genetic relationships between scrotal circumference, heifer pregnancy, and stayability in Nellore cattle

Melis

Eler

Rosa

et al. 2010

Journal of Animal Science

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Scrotal circumference data from 47,605 Nellore young bulls, measured at around 18 mo of age (SC18), were analyzed simultaneously with 27,924 heifer pregnancy (HP) and 80,831 stayability (STAY) records to estimate their additive genetic relationships. Additionally, the possibility that economically relevant traits measured directly in females could replace SC18 as a selection criterion was verified. Heifer pregnancy was defined as the observation that a heifer conceived and remained pregnant, which was assessed by rectal palpation at 60 d. Females were exposed to sires for the first time at about 14 mo of age (between 11 and 16 mo). Stayability was defined as whether or not a cow calved every year up to 5 yr of age, when the opportunity to breed was provided. A Bayesian linear-threshold-threshold analysis via Gibbs sampler was used to estimate the variance and covariance components of the multitrait model. Heritability estimates were 0.42 ± 0.01, 0.53 ± 0.03, and 0.10 ± 0.01, for SC18, HP, and STAY, respectively. The genetic correlation estimates were 0.29 ± 0.05, 0.19 ± 0.05, and 0.64 ± 0.07 between SC18 and HP, SC18 and STAY, and HP and STAY, respectively. The residual correlation estimate between HP and STAY was -0.08 ± 0.03. The heritability values indicate the existence of considerable genetic variance for SC18 and HP traits. However, genetic correlations between SC18 and the female reproductive traits analyzed in the present study can only be considered moderate. The small residual correlation between HP and STAY suggests that environmental effects common to both traits are not major. The large heritability estimate for HP and the high genetic correlation between HP and STAY obtained in the present study confirm that EPD for HP can be used to select bulls for the production of precocious, fertile, and long-lived daughters. Moreover, SC18 could be incorporated in multitrait analysis to improve the prediction accuracy for HP genetic merit of young bulls.

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Section: Estimates Of Heritabilitiessupporting

confidence: 79%

Section: Estimates Of Heritabilitiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Additive genetic relationships between scrotal circumference, heifer pregnancy, and stayability in Nellore cattle

Melis

Eler

Rosa

et al. 2010

Journal of Animal Science

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“…Finally, the heritability estimate of 0.54 ± 0.03 obtained in this study for HP confirms the existence of significant genetic variance for this trait as well. Similar heritability values in Nellore cattle (0.57 ± 0.11, 0.61 ± 0.10, and 0.58 ± 0.13) were reported by Eler et al (2002Eler et al ( , 2004 and Pereira et al (2007). However, in Bos taurus populations, Evans et al (1999) and Doyle et al (2000) found lower heritability estimates for Hereford and Angus breeds (0.14 ± 0.18, and 0.21 ± 0.12, respectively).…”

Section: Heritabilitiessupporting

confidence: 69%

Additive genetic relationship of longevity with fertility and production traits in Nellore cattle based on bivariate models

Melis¹,

Oliveira²,

Eler³

et al. 2010

Genet. Mol. Res.

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ABSTRACT. Survival or longevity is an economically important trait in beef cattle. The main inconvenience for its inclusion in selection criteria is delayed recording of phenotypic data and the high computational demand for including survival in proportional hazard models. Thus, identification of a longevity-correlated trait that could be recorded early in life would be very useful for selection purposes. We estimated the genetic relationship of survival with productive and reproductive traits in Nellore cattle, including weaning weight (WW), post-weaning growth (PWG), muscularity (MUSC), scrotal circumference at 18 177 ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 9 (1): 176-187 (2010) Genetic relationship of longevity with fertility traits in Nellore cattle months (SC18), and heifer pregnancy (HP). Survival was measured in discrete time intervals and modeled through a sequential threshold model. Five independent bivariate Bayesian analyses were performed, accounting for cow survival and the five productive and reproductive traits. Posterior mean estimates for heritability (standard deviation in parentheses) were 0.55 (0.01) for WW, 0.25 (0.01) for PWG, 0.23 (0.01) for MUSC, and 0.48 (0.01) for SC18. The posterior mean estimates (95% confidence interval in parentheses) for the genetic correlation with survival were 0. 16 (0.13-0.19), 0.30 (0.25-0.34), 0.31 (0.25-0.36), 0.07 (0.02-0.12), and 0.82 (0.78-0.86) for WW, PWG, MUSC, SC18, and HP, respectively. Based on the high genetic correlation and heritability (0.54) posterior mean estimates for HP, the expected progeny difference for HP can be used to select bulls for longevity, as well as for post-weaning gain and muscle score.

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“…Table 2. Spearman correlation of all animals (above diagonal) and sires (below diagonal) between predicted breeding values of AFC trait and percentage of sires in common between models at 1% (above diagonal) and 10% (below diagonal) selection percentages Pereira et al (2007) studying age at first conception in Nellore cattle population. These authors reported that when considering just the sires the correlation was even lower; and lower the number of animals, more sensitive is the Spearman correlation to slight changes in classification.…”

Section: Methods Comparisonmentioning

confidence: 99%

Genetic evaluation of age at first calving for Guzerá beef cattle using linear, threshold, and survival Bayesian models

Brito

Casellas

Varona

et al. 2018

Journal of Animal Science

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Age at first calving (AFC) is characterized as a censored trait due to missing values provided by recording mistakes and nonoccurrence or delay in calving communication. In this context, we aimed to compare several statistical methods for genetic evaluation of AFC in Guzerá beef cattle under a Bayesian approach. Seven different methods were used for this purpose. The traditional linear mixed model (LM), which considers only uncensored records; the LM with simulated records (SM), which is based on data augmentation framework; the penalty method, in which a constant of 21 d was added to censored records; the bivariate threshold-linear method considering (TLcens) or not (TLmiss) censored information; and the piecewise Weibull proportional hazards model considering (PWPHcens) or not (PWPH) censored records. Heritability estimates ranged from 0.19 (TLcens) to 0.28 (SM) in nonsurvival approaches; and 0.40 and 0.46 to PWPH and PWPHcens methods, respectively. In general, breeding values correlations between different methods and the percentage of selected bulls in common indicated reranking, with these correlation ranging from -0.28 (between SM and PWPH) to 0.99 (between TLmiss and LM). The traditional LM, which considers only uncensored records, should be preferred due to its robustness and simplicity. Based on cross-validation analyses, we conclude that the TLmiss could be also a suitable alternative for breeding value prediction, and censored methods did not improve the analysis.

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Comparison among three approaches for evaluation of sexual precocity in Nellore cattle

Cited by 11 publications

References 16 publications

Additive genetic relationships between scrotal circumference, heifer pregnancy, and stayability in Nellore cattle

Additive genetic relationships between scrotal circumference, heifer pregnancy, and stayability in Nellore cattle

Additive genetic relationship of longevity with fertility and production traits in Nellore cattle based on bivariate models

Genetic evaluation of age at first calving for Guzerá beef cattle using linear, threshold, and survival Bayesian models

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