Faculty of Veterinary Medicine, Urmia University Veterinary Research Forum 2008-8140 17 7 2026 07 01 Hematological, biochemical, and oxidative stress changes in lambs with atresia ani 505 510 737477 10.30466/vrf.2025.2065164.4822 EN Seyed Amir Hossein Hafezian DVM Graduate, Department of Veterinary Clinical Sciences, Faculty of Veterinary Medicine, Lorestan University, Khorramabad, Iran Abbas Raisi Department of Clinical Sciences, Faculty of Veterinary Medicine, Lorestan University, Khorramabad, Iran 0000-0001-8769-4284 Meysam Tehrani-Sharif Department of Clinical Science, Faculty of Veterinary Medicine, Islamic Azad University, Garmsar Branch, Garmsar, Iran Khosro Safari Nikroo Resident of Veterinary Surgery and Anesthesia, Department of Clinical Science, Faculty of Veterinary Medicine, Ferdowsi University, Mashhad, Iran Amir Zakian Department of Clinical Sciences, Faculty of Veterinary Medicine, Lorestan University, Khorramabad, Iran Journal Article 2025 07 08 Anal atresia (AA) is a congenital anorectal malformation in neonatal lambs characterized by failure of the anal membrane to perforate, resulting in the absence of an anal opening. Early diagnosis and surgical correction are essential for improving survival and outcomes. This study evaluated hematobiochemical and oxidative stress parameters in neonatal lambs with non-segmental AA undergoing surgical intervention. Forty-five male lambs diagnosed with non-segmental AA were enrolled and stratified by time of presentation: within 24 hours of birth or 24-72 hours. An additional 45 healthy male lambs served as controls. Hematological and biochemical parameters, including white blood cell count, red blood cell count, hemoglobin, packed cell volume, total protein, C-reactive protein, superoxide dismutase, malondialdehyde, globulin, fibrinogen, and urea were measured at presentation and 3 days post-operatively. All AA lambs underwent surgical correction, with clinical follow-up for 30 days. Significant differences in hematobiochemical indices and oxidative stress markers were observed between AA lambs and healthy controls. Early surgical intervention (within 24 hours) was associated with significantly reduced levels of urea, fibrinogen, and C-reactive protein. It also resulted in lower malondialdehyde concentrations and higher superoxide dismutase activity, indicating decreased oxidative stress and inflammation compared with later intervention. These findings highlight the critical importance of early surgical intervention in neonatal lambs with anal atresia. Timely surgery improves hematological stability, mitigates oxidative damage, and supports better overall recovery. https://vrf.iranjournals.ir/article_737477_36835e144d1485488c41a4e119ac55b2.pdf