author(s)
D Bharali, KC Deka, BC Deka, KC Nath, RK Biswas, LJ Dutta, BK Sarmah and BN Saikia

abstract
For the present study a total of twenty normal cyclic and twenty confirmed silent estrous cows yielding 8 – 20 liters of milk were selected at random. Blood samples were collected from each animal on day 0, 10, 17 and 20 (day 0 of the next cycle) and each sample was analyzed for estimation of calcium, inorganic phosphorus, magnesium, zinc, total protein, glucose and cholesterol by using quality kits. The analysis of variance revealed that mean level of serum calcium, zinc, total protein, and glucose differ highly significant (p< 0.01) between different days of estrous cycle in both silent and normal estrous cows. While serum inorganic phosphorus and cholesterol did not differ significantly while serum magnesium differed significantly (p< 0.05) between different days but all above differed highly significant (p< 0.01) among different days of estrous cycle in silent and normal estrus cows.