genetic and non-genetic correlations of the average somatic cell score (scs) at different stages oflactation (100, 150, 200, 305 and 365 days in milk) with lactation performance were estimated based on thefirst lactation records of iranian holstein calving during 2000 to 2009. (co) variance components wereestimated using derivative-free reml based on multiple traits animal models. the estimated...