Mineral precision feeding for gestating sows
Résumé
Precision feeding strategy (PF), with the individual and daily mixing of two diets with different lysine content (high
or low), was previously reported to reduce protein intake and N excretion by 25% compared to a conventional single diet feeding (CF). The effect of PF on minerals utilization has not been reported yet, even if it seems relevant to maintain sow’s productivity and health, as well as for economic and environmental reasons. The objective of this study, realized within the Horizon 2020 EU Feed-a-Gene program (grant agreement n°633531), was to report the variations of digestible P (dP) and total Ca requirements among sows and during gestation and to test if PF based on lysine requirement could also be relevant for P and Ca. A dataset of 2,511 gestations reporting sows’ characteristics at insemination and farrowing performance was used as an input for a Python model, based on InraPorc®, predicting nutrients requirements over gestation. Simulations were ran for PF (low: 3.0 g SID lysine/kg, 2.0 g dP/kg; high: 6.5 g SID lysine/kg, 3.3 g dP/kg) and CF (4.8 g SID lysine/kg, 2.5 g dP/kg). The influence of parity (P1, P2, P3+), litter size, and week of gestation on dP and Ca requirements was analysed applying a mixed model. Requirements ranged from 0.88 to 4.14 g/kg for dP and from 2.53 to 13.6 g/kg for Ca. They markedly increased after week 9, increased with litter size and decreased with parity. Compared to CF, average dietary SID lysine and dP content for PF were lower by 27 and 12%, respectively. Over the first 80 days of gestation, all PF and CF sows were fed more than their dP requirement in both strategies. Most of the dP deficits occurred during the last 3 weeks of gestation with 2.9% P deficient sows with PF against 10% with CF. Similar results were obtained for Ca. Mineral PF based on lysine requirements appear less efficient to reduce excessive supplies of P and Ca than for lysine. This is related to differences between P and lysine dynamic of evolution of requirements with time. Nevertheless, the results clearly indicate that precision feeding with the individual and daily mixing of two diets with different P and Ca contents reduced dP intake and consequently P excretion as well as the risk of P deficient sows at the end of the gestation.