Developmental programming in dogs.

Developmental programming in dogs, although less studied than in other species, encompasses both nutritional and behavioural influences during gestation and early life. The most critical window corresponds to the first 120 days (pregnancy followed but the first two months of dog's life), considered the canine equivalent of the human "first 1000 days of life." Low birth weight, result from the intra-uterine growth, is one of the most documented examples of developmental programming in this species. Its consequences extend long beyond the neonatal period: while early effects include disproportionate head development and increased mortality during the first three weeks, long-term effects include a greater predisposition to overweight in adulthood. Gestational programming is modulated by the dam's diet, which can affect birth weight, neonatal and paediatric health, and particularly inflammatory status. However, the postnatal period provides opportunities to counteract prenatal influences: the risk of neonatal mortality in low-birth-weight puppies that achieve adequate early growth during the first two days of life becomes similar to that of normal-birth-weight littermates. Conversely, excessive growth during the first weeks of life is suspected to increase the likelihood of adult overweight, highlighting the need for precise management of neonatal and paediatric growth to ensure healthy adult trajectories. Early-life behavioural programming, through maternal behaviour and environmental exposures, is also essential in shaping dogs for their future societal roles. Overall, developmental programming appears to be a key determinant of lifelong physical and mental health in dogs.