Estimation of genetic parameters for longevity considering the cow’s age at last calving

• Published in: Journal of applied genetics Vol. 58; no. 1; pp. 103 - 109
• Main Authors: Caetano, Sabrina L., Rosa, Guilherme J. M., Savegnago, Rodrigo P., Ramos, Salvador B., Bernardes, Priscila A., Bezerra, Luiz A. F., Lôbo, Raysildo B., de Paz, Claudia C. P., Munari, Danísio Prado
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-02-2017; Springer; Springer Nature B.V
• Subjects: Age Factors; Analysis; Animal Genetics and Genomics; Animal Genetics • Original Paper; Animals; Beef cattle; Biomedical and Life Sciences; Breeding; Cattle; Cattle - genetics; Criteria; Farms; Female; Fertility - genetics; Hazards; Heritability; Human Genetics; Life Sciences; Longevity; Longevity - genetics; Male; Microbial Genetics and Genomics; Parameter estimation; Parturition; Plant Genetics and Genomics; Pregnancy; Pregnancy, Animal - genetics; Proportional Hazards Models; Survival; Survival analysis; Weibull distribution; Brazil; Beef cattle; Survival analysis; Heritability; Weibull model
• ISSN: 1234-1983; 2190-3883
• DOI: 10.1007/s13353-016-0353-6

The aim of this study was to estimate heritability and predict breeding values for longevity among cows in herds of Nellore breed, considering the trait cow’s age at last calving (ALC), by means of survival analysis methodology. The records of 11,791 animals from 22 farms were used. The variable ALC has been used by a criterion that made it possible to include cows not only at their first calving but also at their ninth calving. The criterion used was the difference between the date of each cow’s last calving and the date of the last calving on each farm. If this difference was greater than 36 months, the cow was considered to have failed and uncensored. If not, this cow was censored, thus indicating that future calving remained possible for this cow. The survival model used for the analyses was the proportional hazards model, and the base risk was given by a Weibull distribution. The heritability estimate obtained was equal to 0.25. It was found that the ALC variable had the capacity to respond to selection for the purpose of increasing the longevity of the cows in the herds.