Neonatal puppies and kittens face a critical period after birth, during which their health depends heavily on the microorganisms they acquire from their mothers and environment. These microorganisms, known as the gut microbiota, help newborns develop their immune systems, digest nutrients, and protect against disease. This review explores how these microorganisms are transferred from the mother to her offspring before, during, and after birth, including the process of delivery, nursing, and mate