Background: Infectious diarrhea of newborns calves is one of the biggest health problems in beef and dairy industries in Basrah, Iraq, Group A rotavirus considers major cause of gastroenteritis in newborn calve of buffalo in the world, leading to serious economic losses specifically in developing countries. The infection has short incubation period, non-viremic, and profuse diarrhea.Methods: Buffalo calves with diarrhea were carefully examined and a sample of their excrement was collected for this particular study. The calves ranged in age from one to thirty days and were equally split between males and females. We found out whether the calves were girls or boys. The calves' ages were considered throughout the sorting process; they originated from different regions of Iraq's Basrah governorate. Moreover, they were further separated into four separate age groups. Blood samples were collected from calves infected with rotavirus so that the objectives of this research could be fulfilled. Biochemical and hematological studies were the intended purposes of the blood sample collection. Finding out how these samples fared in comparison to the control samples in the group was the next stage. Laboratory diagnostics used real-time polymerase chain reaction (PCR), while field diagnostics used a rotavirus antigen fast test kit. Both techniques were used in tandem.Results: With the use of a field-based rotavirus antigen fast detection kit and real-time polymerase chain reaction, 19 out of 30 samples tested positive for rotavirus antigen. Nineteen out of one hundred samples came back positive. Along with it, the highest infection rates were recorded in January (30.7%) and among children aged five to fourteen (27.5%). The afflicted males and females did not vary significantly from one another statistically. The clinical signs of infected calves were also documented. Symptoms included anorexia with or without a loss of suckling ability, lose or somewhat solid stools, mucous, and a milky or light-yellow color. Some of the other symptoms included signs of dehydration, although to varying degrees. Nothing stood out while comparing the patients' vital indicators. In the infected group, sodium levels dropped significantly, and monocyte and lymphocyte production skyrocketed. If we look at potassium levels, we see that there was no statistically significant difference between the infected and control groups. Infected calves had substantially greater levels of red blood cell count, panel C viral load, hemoglobin B, and total lipid content (TLC) when compared with healthy calves.Conclusion: The study record and suggests the role of rotavirus group A as a serious cause of diarrhea in newborns buffalo calves in Basrah governorate, Iraq.Keywords: Rotavirus; Group A; Buffalo; Basrah Governorate