genetic evaluation of survival trait in baluchi sheep using gibbs sampling method

the aim of this study was to estimate the genetic trend and genetic parameters of survival traits in baluchi sheep using survival records from 27978 baluchi sheep, which were collected by the animal breeding center of iran during1979 to 2009. genetic parameters of lamb survival from 1 to 400 days of age and from 1 to the last recording date. traits were estimated using animal model (with or without permanent environment of dam) for right censored data assuming an exponential distribution via gibbs sampling. effect of year and month of birth, sex, litter size and herd were assumed as fixed. the posterior mean of direct heritability for survival from 1 to 400 days of age and from 1 to the last recording date in first and second model ranged from 0.135- 0.158 and 0.085- 0.168, respectively. posterior mean permanent variance ratio was 0.076 for survival from 1 to 400 days of age and 0.144 for survival from1 to last recording date. the genetic trend for these traits was −0.0005 and −0.001, respectively. heritability for survival trait suggested that genetic selection for this trait would be effective in the breeding programs.