A cluster-randomized trial in Chad's pastoral regions found that supplementing livestock feed during dry season dramatically reduced child malnutrition rates. Among 821 children across 52 villages, global acute malnutrition dropped from 47.4% in control areas to 22.2% in intervention communities, while severe acute malnutrition fell from 19.4% to 4.4%. The intervention combined livestock feed supplementation, zoonotic risk mitigation, and nutrition counseling, resulting in 588ml more daily milk per household and 102ml additional milk consumption per child. This represents a paradigm shift from reactive treatment toward prevention by addressing root causes embedded in pastoral livelihoods. The approach targets the predictable dry-season malnutrition peak when declining pasture reduces milk availability and increases disease exposure. Children in intervention areas also showed substantially lower rates of diarrheal disease and respiratory infections. The findings suggest that strengthening livestock systems could prevent millions of malnutrition cases across Africa's drylands, where similar seasonal patterns persist. However, as this is a preprint awaiting peer review, these promising results require validation before widespread implementation.