Survival analysis on calving interval and gestation length in Simmental x South Anatolian Red F1XB1 crossbred cows B
Abstract
The objective of this study was to compare the survival analysis for calving interval and gestation length in 1Simmental x South Anatolian Red crossbred F1XBBBOctober 1991, of which 3.10% were censored. The mean calving interval was 382.26 days (15.39 S.D) for young cow group while it was 386.27 days (8.90 S.D) for old cow group. The mean calving interval in young cow group is shorter than old cow group (p<0.01). The mean gestation length was 276.04 days (10.55 S.D) for young cow group while it was 278.89 days (9.63 S.D) for old cow group. The mean gestation length in young cow group was 2 days shorter than old cow group (p<0.001). The distribution of longevity data is extremely skewed. The methods based on assumptions of normality may give biased parameter estimates. Survival analysis to estimate breeding values for longevity should be able to cope with censored data and time dependent variables
References
- Boichard D (1990): Estimation of the economic value of conception rate in dairy cattle. Livestock Prod Sci, 24, 187 – 204.
- Breslow NE (1970): A generalized Kruskal – Wallis test for comparing k samples subject to unequal patterns of censorship. Biometrika, 57, 579 – 594.
- Brown CC (1983): The statistical comparison of relative survival rates. Biometrics, 39, 941 -948.
- Buckley JD (1984): Additive and multiplicative models for relative survival rates. Biometrics, 40, 51 – 62.
- Cox DR (1975): Partial likelihood. Biometrika, 62, 269 – 276.
- Çilek S, Tekin ME (2005): Environmental factors affecting milk yield and fertility traits of Simmental cows raised at the Kozova state farm and phenotypic correlations between these traits. Turk J Vet Anim Sci, 29, 987-993.
- Ducrocq V (1997): Survival analysis, a statistical tool for longevity data. 48 th. Annual Meeting of the EAAP, Vien, Austria.
- Ducrocq V (1994): Statistical analysis of length of productive life for dairy cows of the Normande breed. J Dairy Sci, 77, 855-866.
- Famula TR (1981): Exponential stayability model with censoring and covariates. J Dairy Sci, 64, 538.
- Gehan EA (1965): A generalized Wilcoxon test for comparing arbitrarily singly censored samples. Biometrika, 52, 203 – 223.
- Kaplan EL, Meier P (1958): Nonparametric estimation from incomplete observations. J Amer Stat Assoc, 53, 457 – 481.
- Kumlu S, Akman N (1999): Türkiye damızlık siyah alaca sürülerinde süt ve döl verimi. Lalahan Hay Araşt Enst Derg, 39, 1-15.
- Miller RG (1981): Survial Analysis. John Wiley and Sons, NY.
- Smith SP (1983): The Extension of Failure Time Analysis to Problems of Animal Breeding. PhD Diss, Cornell Univ, Ithaca, NY.
- Smith SP, Quass RL (1984): Productive lifespan of bull progeny groups: failure time analysis. J Dairy Sci, 67, 2999-3007.
- SPSS ver. 11.5, Statistical Packet for Social Sciences, SN: 902 4147, Chicago, IL.
Simental x Güneydoğu Anadolu Kırmızısı F1XBB1 melezi ineklerin buzağılama aralığı ve gebeliksüresinin yaşam analizi ile incelenmesi
Abstract
Bu çalışmada, Simmental x Güneydoğu Anadolu F1XBBmelezi genç ve ergin çağdaki ineklerde, buzağılama aralığı ve gebelik süreleri, yaşam analizi metodu ile incelenmiştir. Çalışmanın verileri, Ceylanpınar tarım işletmesinde Ocak 1987 ile Ekim 1999 tarihleri arasında yer alan 1775 laktasyon kayıdından elde edilmiştir. Verilerin %3.1’i sensörlüdür. Genç ineklerin ortalama buzağılama aralığının, (382.26 ± 15.39 Gün) ergin yaştakilerden (386.27 ± 8.9 Gün) daha kısa olduğu (p<0.01), ergin yaştakilerin gebelik süresinin (278.89 ± 9.63 S) gençlerden (276.04 ±10.55 S) 2 gün daha fazla olduğu görülmüştür (p<0.001). Yaşam verilerine ait damızlık değerlerinin tahmin edildiği çalışmalarda normallik varsayımı üzerine kurulu metotlar yanlı tahminler vermektedir. Zamana bağımlı ve sansürlü verilerin analizinde yaşam analizi metodu kullanılmalıdır
References
- Boichard D (1990): Estimation of the economic value of conception rate in dairy cattle. Livestock Prod Sci, 24, 187 – 204.
- Breslow NE (1970): A generalized Kruskal – Wallis test for comparing k samples subject to unequal patterns of censorship. Biometrika, 57, 579 – 594.
- Brown CC (1983): The statistical comparison of relative survival rates. Biometrics, 39, 941 -948.
- Buckley JD (1984): Additive and multiplicative models for relative survival rates. Biometrics, 40, 51 – 62.
- Cox DR (1975): Partial likelihood. Biometrika, 62, 269 – 276.
- Çilek S, Tekin ME (2005): Environmental factors affecting milk yield and fertility traits of Simmental cows raised at the Kozova state farm and phenotypic correlations between these traits. Turk J Vet Anim Sci, 29, 987-993.
- Ducrocq V (1997): Survival analysis, a statistical tool for longevity data. 48 th. Annual Meeting of the EAAP, Vien, Austria.
- Ducrocq V (1994): Statistical analysis of length of productive life for dairy cows of the Normande breed. J Dairy Sci, 77, 855-866.
- Famula TR (1981): Exponential stayability model with censoring and covariates. J Dairy Sci, 64, 538.
- Gehan EA (1965): A generalized Wilcoxon test for comparing arbitrarily singly censored samples. Biometrika, 52, 203 – 223.
- Kaplan EL, Meier P (1958): Nonparametric estimation from incomplete observations. J Amer Stat Assoc, 53, 457 – 481.
- Kumlu S, Akman N (1999): Türkiye damızlık siyah alaca sürülerinde süt ve döl verimi. Lalahan Hay Araşt Enst Derg, 39, 1-15.
- Miller RG (1981): Survial Analysis. John Wiley and Sons, NY.
- Smith SP (1983): The Extension of Failure Time Analysis to Problems of Animal Breeding. PhD Diss, Cornell Univ, Ithaca, NY.
- Smith SP, Quass RL (1984): Productive lifespan of bull progeny groups: failure time analysis. J Dairy Sci, 67, 2999-3007.
- SPSS ver. 11.5, Statistical Packet for Social Sciences, SN: 902 4147, Chicago, IL.
Details
| Primary Language | English |
|---|---|
| Subjects | Veterinary Surgery |
| Journal Section | Research Article |
| Authors | |
| Publication Date | September 1, 2007 |
| Published in Issue | Year 2007 |