Effect of the first and second postpartum partial milking on blood serum calcium concentration in dairy cows

Parturient paresis and subclinical hypocalcemia are frequent metabolic disorders in dairy cows postpartum. The aim of this study was to determine the effect of postpartum partial milking in the first two milkings on blood serum calcium concentration in dairy cows. Twenty multiparous Holstein dairy cows were randomized into two groups. Cows of group 1 ( n = 10) were partially milked at the first and second milking postpartum. Cows of group 2 ( n = 10) were completely milked. Blood samples were collected from all animals 5- 7 days before calving, within 30 min after calving, and 4, 8, 12, 16, 20, 24, 28, and 32 h after calving for deter - mination of serum calcium (Ca), phosphorus (P), and magnesium (Mg) concentrations. Colostrum production was registered and sampled in the first and second milking. Concentration of Ca in colostrum was determined by atomic absorption spectrophotometry. Serum Ca and P concentrations decreased in both groups after par - turition (