Comparison among three approaches for evaluation of sexual precocity in Nellore cattle
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....
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2007-01-01
|
| Series: | Animal |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S1751731107392732 |
| _version_ | 1818658367443304448 |
|---|---|
| author | E. Pereira H.N. Oliveira J.P. Eler J.A. Silva M.H. Van Melis |
| author_facet | E. Pereira H.N. Oliveira J.P. Eler J.A. Silva M.H. Van Melis |
| author_sort | E. Pereira |
| collection | DOAJ |
| description | 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. |
| first_indexed | 2024-12-17T03:56:15Z |
| format | Article |
| id | doaj.art-ddcddd3952cc4900bdb8efb0d143fd7d |
| institution | Directory Open Access Journal |
| issn | 1751-7311 |
| language | English |
| last_indexed | 2024-12-17T03:56:15Z |
| publishDate | 2007-01-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Animal |
| spelling | doaj.art-ddcddd3952cc4900bdb8efb0d143fd7d2022-12-21T22:04:37ZengElsevierAnimal1751-73112007-01-0113411418Comparison among three approaches for evaluation of sexual precocity in Nellore cattleE. Pereira0H.N. Oliveira1J.P. Eler2J.A. Silva3M.H. Van Melis4Departamento de Melhoramento e Nutrição Animal, FMVZ/UNESP, PO Box 560, 18618-000, Botucatu, SP, BrazilDepartamento de Melhoramento e Nutrição Animal, FMVZ/UNESP, PO Box 560, 18618-000, Botucatu, SP, BrazilDepartamento de Ciências Básicas, FZEA/USP, PO Box 23, 13635-900, Pirassununga, SP, BrazilEEZS-SP - IZ/APTA/SAA-SP, CP 63, 14460-000, Sertãozinho, SP, BrazilDepartamento de Ciências Básicas, FZEA/USP, PO Box 23, 13635-900, Pirassununga, SP, BrazilRestricted 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.http://www.sciencedirect.com/science/article/pii/S1751731107392732beef cattlelinear modelsprecocitypregnancymesurvival analysis |
| spellingShingle | E. Pereira H.N. Oliveira J.P. Eler J.A. Silva M.H. Van Melis Comparison among three approaches for evaluation of sexual precocity in Nellore cattle Animal beef cattle linear models precocity pregnancy mesurvival analysis |
| title | Comparison among three approaches for evaluation of sexual precocity in Nellore cattle |
| title_full | Comparison among three approaches for evaluation of sexual precocity in Nellore cattle |
| title_fullStr | Comparison among three approaches for evaluation of sexual precocity in Nellore cattle |
| title_full_unstemmed | Comparison among three approaches for evaluation of sexual precocity in Nellore cattle |
| title_short | Comparison among three approaches for evaluation of sexual precocity in Nellore cattle |
| title_sort | comparison among three approaches for evaluation of sexual precocity in nellore cattle |
| topic | beef cattle linear models precocity pregnancy mesurvival analysis |
| url | http://www.sciencedirect.com/science/article/pii/S1751731107392732 |
| work_keys_str_mv | AT epereira comparisonamongthreeapproachesforevaluationofsexualprecocityinnellorecattle AT hnoliveira comparisonamongthreeapproachesforevaluationofsexualprecocityinnellorecattle AT jpeler comparisonamongthreeapproachesforevaluationofsexualprecocityinnellorecattle AT jasilva comparisonamongthreeapproachesforevaluationofsexualprecocityinnellorecattle AT mhvanmelis comparisonamongthreeapproachesforevaluationofsexualprecocityinnellorecattle |