A comparative study on serum biochemical constituents was carried out in pregnant, estrus, anestrus and regular cyclic Jersey crossbred cattle. A total of 48 healthy Jersey crossbred cattle (n=48), aged 3-6 years with body condition score of 5-6 were selected and they were divided into four groups, each group comprised of twelve (n=12) animals (Group I: Pregnant, Group II: Estrus, Group III: Anestrus and Group IV: Regular cyclic). Experimental cows were properly vaccinated and dewormed as per the schedule of the farm. In morning, prior to concentrate feeding, the blood samples were collected in heparinized vacutainer and immediately transported to the laboratory. The blood samples were centrifuged at 3000 × g for 15 min. Serum samples were separated and kept at -20 °C until estimation of biochemical profiles. Concentration of serum total protein, albumin, globulin, glucose, total cholesterol was significantly (p<0.05) higher in pregnant as compared to anestrus animals which was recorded as the lowest among the four groups. Regular cyclic cows had non-significantly higher concentration of serum protein, glucose, total cholesterol and creatine as compared to anestrus cows. Similarly, concentration of serum blood urea nitrogen (BUN), creatinine and liver functional enzymes (aspartate aminotransferase; AST, alanine aminotransferase; ALT and alkaline phosphatase; ALP) was higher in pregnant as compared to anestrus cows. However, anestrus animals were had nonsignificantly higher concentration of BUN and liver enzymes as compared to regular cyclic cows. Therefore, these findings implied that day 45-60 postpartum, blood glucose, total protein and BUN and total cholesterol have significant impact on the cyclicity of Jersey crossbred cows. Further research on mechanism of these metabolites on cyclicity of postpartum cow is required to confirm these findings.