Effect of calcium supplementation at calving on postpartum performance and milk composition of dairy cows

The aim of the study was to evaluate the effect of calcium supplementation after calving on performance and milk composition of dairy cows during the first 28 days of lactation and lactational performance (days open, lactation length, cumulative lactation milk yield, and 305-d mature equivalent milk). Twenty multiparous Holstein cows were randomly assigned to 1 of 2 treatments: (1) oral supplement of Ca bolus (CAB; n= 9) containing calcium formate and lithothamnion calcareum (red coral alga) immediately and 12 - 18 h post-calving and (2) Control (CON; n = 11) that did not receive oral Ca. Milk yield was recorded daily and data of body weights and milk composition were collected weekly from calving to postpartum 28 days. Ca supplementation at calving tended to increase daily milk yield (P= 0.062) and increase total milk yield (P= 0.049) for postpartum 28 days. However, body weights and milk composition, and lactational performance did not differ by the treatment. In conclusion, supplementing dairy cows with oral Ca boluses at parturition improves milk yield during early lactation, but not entire lactation. Key Words: Ca-Bolus, dairy cow, calving, milk yield, milk composition