This article highlights that successful calf rearing depends on far more than feeding alone. Environmental conditions, hygiene, thermal comfort, water availability, and low-stress handling play a critical role in calf health, immune function, and long-term performance. Deviations from the thermal neutral zone increase energy demands and can impair rumen development and growth. The key message is clear: a holistic management approach is essential to maximize calf survival, vitality, and future productivity in modern dairy systems. With comments on a "Hoard´s Dairyman"-article (January 25th, 2026) by AI Kertz: https://hoards.com