The Effects of Structured Lactation Nutrition Education and Dali ni Horbo Supplementation on Maternal Nutritional Intake, Breastfeeding Practices, Infant Growth, and Gut Microbiota: A Randomized Controlled Trial

Inclusion Criteria: * Lactating mothers aged 18-40 years. * Having a healthy, singleton infant aged 0-1 month at enrollment. * Residing within the service areas of the participating primary healthcare centers in Medan, Indonesia. * Currently breastfeeding and intending to continue breastfeeding throughout the study period. * Able to consume Dali ni Horbo and willing to follow the assigned intervention. * Willing to participate in all study assessments, including dietary assessment, anthropometric measurements, and infant stool collection. * Able to communicate effectively and complete the study questionnaires. * Willing to provide written informed consent. Exclusion Criteria: * Mothers or infants with medical conditions that may significantly affect breastfeeding, maternal nutritional status, nutrient metabolism, or infant growth. * Mothers with severe postpartum complications or conditions requiring hospitalization. * Infants with congenital abnormalities, gastrointestinal disorders, metabolic diseases, severe infections, or other conditions affecting feeding or growth. * Infants born preterm or with low birth weight, according to the study protocol. * Mothers with a known allergy or intolerance to buffalo milk, cow's milk, or dairy products. * Mothers following a medically prescribed restrictive diet that could affect the study outcomes. * Current participation in another nutritional or clinical intervention study. * Use of nutritional supplements, probiotics, antibiotics, or other treatments that may substantially affect maternal nutrient intake or infant gut microbiota, unless permitted by the study protocol. * Inability or unwillingness to comply with the intervention and follow-up procedures.