Additive genetic relationships between heifer pregnancy and scrotal circumference in Nellore cattle1

Jm, Evans; Golden, Bruce L.; Bourdon, R. M.; Long, K L

doi:10.2527/2004.8292519x

Cited by 101 publications

(90 citation statements)

References 15 publications

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“…Bos indicus breeds have on average later ages at puberty than Bos taurus breeds. Eler et al (2004) argues that because puberty is later, genetic variability for fertility traits like heifer pregnancy rate seems to be much higher than that in Bos taurus breeds These findings correspond with the results of this study. The Afrikaner is an indigenous breed to South Africa and classified as Bos taurus africanus (Frisch et al, 1997;Hanotte et al, 2002); animals that have similar characteristics to both Bos indicus and Bos taurus breeds.…”

Section: Discussionsupporting

confidence: 91%

“…Also, the contemporary groups were small due to the exclusion of homogenous groups. When Eler et al (2004) used the weaning management of heifers as contemporary groups, they found that it led to the exclusion of 23% of the data (due to homogenous groups) but concluded that heifer pregnancy is highly heritable, regardless of the contemporary group definition.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Non-linear model analysis of categorical traits related to female reproduction efficiency in beef cattle

Rust¹,

Schoeman

Westhuizen

et al. 2010

SA J. An. Sci.

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________________________________________________________________________________ AbstractThe utilization of non-linear threshold models and linear animal models to estimate variance components for categorical reproductive traits in beef cattle was investigated. Three traits, retention (RET), stayability (STAY) and calf tempo (CT) were defined. The data set consisted of 36 880 Afrikaner beef cattle measurements recorded over a period of 10 years. After editing, the records of 7 746 females from 473 sires were available for the genetic parameter estimation for RET. The corresponding number of records for STAY and CT were 3 018 (243 sires) and 7 653 (465 sires), respectively. Using GFCAT, sire variances for RET, STAY and CT were estimated as 0.202, 0.072 and 0.114, respectively. With error variances pre-set to one, the heritability estimates on the underlying scale were calculated as 0.67, 0.27 and 0.41 for RET, STAY and CT, respectively. From the three traits analyzed in this study CT probably reflects the true fertility of the bull's female progeny best.________________________________________________________________________________

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Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 99%

Non-linear model analysis of categorical traits related to female reproduction efficiency in beef cattle

Rust¹,

Schoeman

Westhuizen

et al. 2010

SA J. An. Sci.

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show abstract

“…Using 986 Hereford heifers, they obtained a heritability estimate of 0.14 with a standard error of 0.09. In a larger data set, Eler et al (2004) used a categorical animal model and method R to obtain heritability estimates (standard error) of 0.61 (0.10) and 0.68 (0.09) for heifer pregnancy. These estimates are unusually large, and may reflect the pitfalls of using an animal threshold model jointly with a heuristic approach to estimation.…”

Section: Resultsmentioning

confidence: 99%

“…In beef cattle, focus has been on calving date (Bourdon and Brinks, 1983;Buddenberg et al, 1990), or the related calving day (Ponzoni, 1992) or days to calving (Meyer et al, 1990;Johnston and Bunter, 1996;Donoghue et al, 2004a). Recently, heifer pregnancy status and the outcome of subsequent rebreeding have attracted interest (Evans et al, 1999;Doyle et al, 2000;Eler et al, 2004). Calving success (CS) has been studied as well (Meyer et al, 1990;Mercadante et al, 2003;Donoghue et al, 2004d).…”

Section: Introductionmentioning

confidence: 99%

Genetic variability in calving success in Aberdeen Angus cows under extensive recording

Urioste

Chang

Naya

et al. 2007

Animal

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Data from 2032 Uruguayan Aberdeen Angus cows under extensive management and recording practices were analysed with Bayesian threshold-liability sire models, to assess genetic variability in calving success (CS), defined as a different binary trait for each of the second (CS2), third (CS3) and fourth (CS4) calving opportunities. Sire (herd) variances ranged from 0.08 to 0.11 (0.10 to 0.20) and heritability from 0.27 to 0.35, with large credibility intervals. Correlations between herd effects on CS at different calving opportunities were positive. Genetic correlation between CS2 and CS4 was positive (0.68), whereas those involving adjacent calving opportunities (CS2-CS3 and CS3-CS4) were negative, at 20.39 and 20.54, respectively. The residual correlation CS2-CS3 was negative (20.32). The extent of uncertainty associated with the posterior estimates of the parameters was further evaluated through simulation, assuming different true values (20.4, 20.2, 10.2 and 10.4) for the genetic correlations and changes in the degree of belief parameters of the inverse Wishart priors for the sire covariance matrix. Although inferences were not sharp enough, CS appears to be moderately heritable. The quality of data recording should be improved, in order to effect genetic improvement in female fertility.

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“…Nevertheless, in a recent study, Eler et al (2004) also found high heritability for HP14 even with the animal model (0.68).…”

Section: Genetic Parametersmentioning

confidence: 89%

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

Pereira

Oliveira

Eler³

et al. 2007

Animal

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Restricted breeding seasons used in beef cattle produce censored data for reproduction traits measured in regard to these seasons. To analyze these data, adequate methods must be used. The objective of this paper was to compare three approaches aiming to evaluate sexual precocity in Nellore cattle. The final data set contained 6699 records of age at first conception (AFC14) (in days) and of heifer pregnancy (HP14) (binary) obtained from females exposed to the bulls for the first time at about 14 months of age. Records of females that did not calve in the following year after being exposed to a sire were considered censored (77.5% of total). The models used to obtain genetic parameters and expected progeny differences (EPDs) were a Weibull mixed and a censored linear model for AFC14 and threshold model for HP14. The mean heritabilities obtained were 0.76 and 0.44, respectively, for survival and censored linear models (for AFC14), and 0.58 for HP14. Ranking and Pearson correlations varied (in absolute values) from 0.54 to 0.99 (considering different percentages of sires selected), indicating moderate changes in the classification. Considering survival analysis as the best selection criterion (that would result in the best response to selection), it was observed that selection for HP14 would lead to a more significant decrease in selection response if compared with selection for AFC14 analysed by censored linear model, from which results were very similar to the survival analysis.

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Additive genetic relationships between heifer pregnancy and scrotal circumference in Nellore cattle1

Cited by 101 publications

References 15 publications

Non-linear model analysis of categorical traits related to female reproduction efficiency in beef cattle

Non-linear model analysis of categorical traits related to female reproduction efficiency in beef cattle

Genetic variability in calving success in Aberdeen Angus cows under extensive recording

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

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