Anion supply in prepartum rations affects the mineral metabolism in primiparous cows. The objective of this study was to evaluate the effect of calcium chloride and dietary calcium sulfate in prepartum heifers’ rations on the composition of colostrum, fat and protein milk content, and total milk production during 305 days of lactation. Forty five Holstein heifers were assigned to three groups (15 per group) 21 days before calving. The heifers received a partially mixed ration (PMR) plus 2.5 kg/cow/day of wheat middlings (CP= 18.5%, neutral detergent fiber= 36.7%). Mineral salts with a dietary cation-anion difference (DCAD) of +200 mEq/kg of dry matter (DM) were added in the control group (TCon); calcium chloride was added in one of the experimental groups (TCICa), and calcium sulfate was added in the other experimental group (TSoCa), both with DCAD= +30 mEq/kg of DM. After calving, they were fed on commercial feed, corn silage, and alfalfa grazing. The content of fat, protein, calcium, phosphorus, and magnesium in the colostrum was not different among the treatments (p0.05). TClCa cows produced a greater average of milk (kg/day), fat and protein corrected milk (kg/day), fat (kg/day), and net energy of lactation (Mcal/day). The TClCa group had higher milk production, and fat (kg) and protein (kg) content than TCon (p0.05), with intermediate values for TSoCa. The supply of calcium chloride in the prepartum of heifers produced differences in milk production and composition during the 305 days of lactation.