Abstract
Aim: This study aims to determine the effects of different physiological parameters of pregnancy, including trimester, parity number, milking status and level of milk yield on the biochemical status of serum calcium (Ca), phosphorus (P) and total protein (TP) in dairy cows to signify the importance of routine metabolic profiling in the dairy sector. Methods: This study involved 3 randomly selected farms of Sitakunda upazila, Chattogram, from which data from 40 randomly selected pregnant cows were collected. Data were collected through direct interviews and using a pre-tested questionnaire. Blood samples were collected from the tail vein, and laboratory tests were done to estimate serum Ca, P and TP levels. Data were analyzed to evaluate the effects of different trimesters, parity numbers, milking status and level of milk yield on serum levels of Ca, P and total protein. Results: The descriptive analysis of this study showed that a significant difference was found in the serum calcium level due to different levels of milk yield (P>0.05, but P<0.10), and calcium levels were high in low-yielding cows in comparison to medium-yielding cows, considering higher mobilization of calcium from bone to blood. However, no significant differences were found in the case of P and total protein due to milk yield (P>0.05). Also, serum levels of Ca, P and total protein were evaluated with no significant differences across trimesters (P>0.05), parity numbers (P>0.05) and milking status (P>0.05). Conclusion: This study found no significant variation in studied metabolites in relation to different stages of pregnancy, except in the case of calcium. Therefore, we suggest a more in-depth study to ensure the variation of metabolic profiles of pregnant cows at their different stages of pregnancy.

Key words: Calcium, Dairy, Management, Milk Yield, Serum