The present investigation was carried out on 36 Crossbred cows from Research Cum Development Project cattle farm, Mahatma Phule Krishi Vidyapeeth, Rahuri and Dept. of Animal Reproduction, Gynaecology and Obstetrics, K.N.P. college of Veterinary Science, Shirwal, Maharashtra. Group I (n= 12, Treatment Group I), Group II (n= 12, Treatment Group II) and Group III (n=12, Control Group). Group I were given orally 50 gm of mineral + vitamin feed supplement 20 days before and 40 days after parturition. Group II were given orally 50 gm of mineral + vitamin feed supplement 20 days before and 40 days after parturition and 100 gm of vitamin supplement 10 days prior to calving. All 3 groups included those animals which were advance pregnant (8 month).

The serum calcium (mg/dl) level before 20 days of parturition, at the time of parturition and after 40 days of parturition were (10.65+0.11, 9.68±0.15, 10.92±0.14), (10.74±0.01, 10.51±0.12, 10.71±0.15), and (11.08+0.01, 11.48±0.16, 10.41±0.1) from Group-I, Group-II and control group, respectively.

The serum magnesium (mg/dl) levels before 20 days of parturition, at the time of parturition and after 40 days of parturition were (2.26±0.09, 2.15±0.32, 2.24±0.11), (2.84±0.02, 2.81±0.04, 2.73±0.04) and (2.70±0.05, 2.46±0.05, 2.38±0.04) from Group-I, Group-II and control group, respectively.

The serum phosphorus (mg/dl) levels before 20 days, at the time of parturition and after 20 days of parturition were (5.60+0.08, 5.47+0.10, 5.60±0.08), (5.78+0.15, 5.86±0.14, 5.72±0.014) and (6.02+0.07, 6.22+0.06, 5.83± 0.13) from group-I, group-II and control group respectively.

The results revealed that serum calcium levels were increased after 40 days of parturition than previous values in both Treatment groups, but in Treatment group II it was higher than Treatment group I. While in Control group serum calcium levels were decreased after 40 days of parturition.