This study aims to estimate the additive genetic correlations (RA) among days open (DO), milk (MY), fat (FY) and protein yield (PY) in lactations 1 to 3 of Holstein herds on pastures-based production systems. The database used had 546,659; 367,774 and 247,158 observations for 1st, 2nd, and 3rd lactation. Data were edited to set records to DO greater than 42 d. Traits for each lactation were considered different and they were analyzed using 6-variate models, with DO and a production trait. The fixed effects were the age at calving and the combined effect of the herd-year-season and the random additive genetic effect of the animal. Estimations were obtained via Gibbs sampling with Gib­bs2f90 program. Heritabilities obtained for each lactation of DO ranged from 0.04 to 0.06, for MY the range was 0.23 to 0.22, for PY from 0.09 to 0.28 and for FY from 0.06 to 0.28. The RA between DO ranged from 0.68 to 0.96, although they were different from 1, most of the values were very high to consider them as different traits. The RA between DO and production traits is presented in Table 1. Results suggest that DO can be considered as one trait, adjusting the model with a fixed effect accounting for different lactations. Unfavorable relationship between DO and production traits may be confirmed, thus is necessary the inclusion of fertility in selection programs, and further estimation of RA analyzing all traits together with a repeatability model. Table 1. Additive genetic correlations among days open (DO), milk (MY), fat (FY) and protein yield (PY) in lactations 1 to 3 of Holstein herds

		Days open
1	2	3
Milk	1	0.39 (0.0375)	0.56 (0.0338)	0.51 (0.0638)
	2	0.49 (0.0357)	0.58 (0.0314)	0.59 (0.0640)
	3	0.40 (0.0335)	0.54 (0.0393)	0.63 (0.0581)
Protein	1	0.43 (0.0456)	0.53 (0.0471)	0.78 (0.0282)
	2	0.44 (0.0425)	0.53 (0.0375)	0.69 (0.0372)
	3	0.46 (0.0601)	0.55 (0.0535)	0.67 (0.0543)
Fat	1	0.41 (0.0751)	0.51 (0.0907)	0.69 (0.0565)
	2	0.54 (0.0604)	0.66 (0.0434)	0.80 (0.0345)
	3	0.34 (0.0620)	0.46 (0.0520)	0.63 (0.0493)