Genetic and Non-Genetic Factors Affecting Longevity of Mehraban Sheep

Longevity records of 26991 Mehraban lambs born from 405 sires and 8114 dams which collected by the Agricultural Organization of Hamedan Province during 1981 to 2011 were used in this study. To determine the fixed effects fitted in statistical model (birth year, birth month, type of birth, age of dam, flock, lamb sex and lamb birth weight and their interactions), the GLM procedure of SAS software was used. Interaction between birth year-lamb sex and all fixed effects except for birth type, dam age and linear covariate variable of lamb birth weight was significant on longevity (P