It was used 10,238 weekly milk production records on the control day from the first 388 lactations of Saanen goats on the evalution of six lactation persistency measures in order to find out which was the best fitted for using in genetic evaluations on this trait. These six evaluated measures are adaptations from those used on dairy cattle, obtained by replacing, in the formula, bovine reference values by the goat ones. The values used in the calculations were obtained from random regression models. Heritability estimates for persistency measures ranged from 0.03 to 0.09. Genetic correlations between persistency measures and milk production until 268 days ranged from -0.64 to 0.67. Because it presented the lowest genetic correlation with production at 268 days (0.14), the persistency measure PS4 obtained by the sum of the genetic values from the 41st to the 240th day of lactation as deviations of production at 40 days of lactation, is the best recommended for genetic evaluations of lactation persistence on Saanen goats. Thus, the selection of the goats with the best persistency of lactation does not change the production at 268 days. Due to the low heritability of this measure (0.03), few responses to selection are expected on this herd.
genetic correlation; lactation peak; milk; selection
