From dam to neonate: microbial, metabolic, and functional pathways shaping early-life development in dogs.

Within minutes, the canine neonate transitions from placental support to respiration, thermoregulation, glucose homeostasis, feeding, and microbial colonization. These events are often considered separately, yet they form a connected developmental process that begins in the dam and continues through birth and lactation. This narrative review integrates evidence on maternal, microbial, metabolic, and functional determinants of early-life development in dogs. During gestation, maternal nutrition, metabolism, endocrine adaptation, and the maternal microbiota can influence fetal growth and maturation without requiring a viable fetal microbiota. At birth, loss of placental support coincides with physiological transition and rapid exposure to maternal and environmental microorganisms. Delivery mode, intrapartum care, antimicrobial exposure, and the interval to effective suckling can therefore affect several components of neonatal adaptation simultaneously. Colostrum and milk continue maternal support by supplying immunoglobulins, energy, growth-promoting factors, microorganisms, and a changing metabolite profile. The neonatal intestinal microbiota changes during the first weeks of life, in parallel with maturation of intestinal, immune, and metabolic functions. Low birth weight, inadequate early growth, hypothermia, hypoglycemia, impaired passive immune transfer, and altered intestinal microbial composition are associated with poor outcome, but their causal relationships remain incompletely resolved. Evidence supports careful management of the dam, prompt neonatal assessment, early colostrum intake, thermal and nutritional support, and longitudinal monitoring of weight and clinical activity. Microbiome-based risk prediction and targeted microbial interventions are plausible, but require prospective, multicenter validation before routine clinical use. An integrated dam-to-neonate framework may improve mechanistic research and early recognition of puppies at risk.