WINTER BONUS MAGAZINE 2026

Nardus Mostert – Technical Advisor: Monogastric Step-up and step-down feeding strategies in swine: Nutritional andmanagement implications for gilts and sows Increased genetic potential and improvedmanagement havemarkedly enhanced sow productivity worldwide, but these gains have intensified nutritional andmetabolic challenges for breeding females. Step-up and step-down feeding strategies are widely applied to align nutrient supply with the dynamic physiological demands of gilts and sows during development, gestation, and lactation. Over the past few decades, sow productivity has increased substantially, with multiple production systems achieving more than 29 piglets weaned per sow per year. While this improvement enhances efficiency, it also places considerable pressure on the breeding female, particularly during critical periods such as gilt development, gestation, and lactation. Nutritional mismanagement during these stages can result in excessive body reserve mobilisation, impaired fertility, and premature culling. Step-up and step-down feeding strategies are designed to synchronise nutrient intake with physiological requirements across the reproductive cycle. Step-up feeding increases nutrient supply during periods of elevated demand, whereas step-down feeding restricts intake during phases of lower requirement to prevent excessive fat deposition. When integrated with objective body condition monitoring, these strategies form the foundation of precision sow feeding. Physiological basis for feeding curve adjustment Parity-related differences First-parity sows differ fundamentally from older sows in nutrient requirements. Young sows are still growing toward mature body size, typically weighing up to 100 kg less than multiparous sows. Consequently, they require additional nutrients for growth while simultaneously supporting pregnancy and subsequent lactation. Older sows, in contrast, have higher maintenance requirements due to greater body mass and often require an additional 400–500 g of feed per day toward the end of gestation simply to maintain body condition. These parity-related differences necessitate differentiated feeding curves. Uniform feeding strategies across parities increase the risk of underfeeding young sows and over conditioning older sows, both of which negatively affect lifetime productivity. Winter 2026 BONUS www.agribonus.co.za 38