Gets the dates of birth for each individual in antibody_data
get_DOBs(antibody_data)the data frame of antibody data. See example_antibody_data
a data frame with individual and birth
Other get_summary:
get_n_alive(),
get_n_alive_group()
if (FALSE) { # \dontrun{
data(example_antibody_data)
get_DOBs(antibody_data)
} # }