Energy requirements for lactating sow : determination by a factorial approach

Abstract

Determination of energy requirements by an empirical approach (field trials) has limits, especially when results have to be extrapolated to other situations. The data obtained from personal and literature studies on energy metabolism of the lactating sow have been used in order to estimate energy requirements according to a factorial approach. The approach is based on estimates of energy requirements for maintenance (110 kcal metabolizable energy : ME per kg^0.75 ) and the efficiencies of utilization of energy from feed (kl = 72 %) and from body reserves (krl = 88 %) for milk production. Energy excreted in milk is calculated from growth of the litter (R² > 0.90). Calculations indicate that ME requirements vary according to sow body weight and, to a large extent, to litterweight gain. On average, they are equivalent to 18 to 20 Mcal ME per day, these values being higher than the spontaneous food intake of lactating sows. The discrepancy between energy requirements and energy intake during lactation has to be considered for recommendation of energy requirements during subsequent pregnancy.