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Gestating sows are often fed a single diet throughout their gestation cycle, leading to situations of nutrients deficiency or excess at the individual level. The purpose of this study was to characterize, over 3 consecutive cycles, the impact of a precision feeding (PF), i.e., dietary supplies adjusted at individual level in terms of quantity (energy intake) and quality (standardized ileal digestible (SID) lysine (Lys) intake), on gestating sows’ productive performance, feeding behavior, environmental outputs, and health status compared with sows fed a conventional feeding (CF, i.e., fixed SID Lys intake). At the start of the trial, 2 batches of 20 Landrace × Large White gestating sows were allocated to one of the 2 feeding strategies (PF vs. CF), based on their parity (1, 2, or 3 and more), body weight, and backfat thickness (BT) 3 days after insemination. The PF strategy consisted in mixing with automatic feeders 2 iso-energetic diets (9.8 MJ/kg of net energy with 3.3 and 8.5 g SID Lys/kg, respectively) in variable proportions at individual and daily levels, whereas for the CF strategy these proportions remained constant throughout gestation (73% and 27%, respectively, resulting in an SID Lys concentration of 4.7 g/kg). Sows were followed over 3 consecutive gestations and the sows remained allocated to the same strategy throughout the study. Some sows were culled before the end of the study and were replaced by other sows who therefore performed only 1 or 2 gestations during the study. Thus, 106 gestations and lactations from 51 sows were fully studied and their data analyzed. The PF strategy allowed the sows to reach more closely the expected BT values at farrowing across cycles than the CF strategy (P< 0.001). The PF sows consumed 16% less SID Lys per gestation than the CF sows (P< 0.001), resulting in a 4% improvement in N efficiency (P< 0.001), with no impact on performance at farrowing (P> 0.10). The sows consumed their daily ration in a single visit whatever the feeding strategy (P= 0.41), but CF sows spent more time in the feeder in cycles 2 and 3 (P< 0.001). Thus, compared to the CF strategy implemented by farmers, the individual and daily nutritional supplies implemented with the PF strategy were more efficient in enabling sows to achieve body condition objectives at farrowing over the long term, also with a reduced SID Lys intake and an improved N efficiency without negative impact on farrowing performances.Precision feeding of gestating sows over 3 consecutive cycles improved the body condition at farrowing (by a better adequacy of energy supplies) and improved nitrogen efficiency (by reducing excess standardized ileal digestible lysine intake), without negative impacts on sows’ performance, feeding behavior or health but with a better potential longevity.In commercial farms, sows are often fed a single diet throughout gestation. This results in a mismatch between feed intake and individual needs, which can lead to complications during farrowing. Precision feeding is a way of providing the sows an individual daily intake in terms of quantity and nutritional quality, by blending different diets using automatic feeders. We investigated the long-term effects of precision feeding of gestating sows, on their performance and feeding behavior. The results showed that precision feeding enabled farrowing body condition targets to be reached over time. Compared to a conventional feeding strategy, amino acid intake was reduced by 16% per gestation with precision feeding, enabling a 4% increase in nitrogen efficiency, with no impact either on the number or average birth weight of born alive piglets. Whatever the feeding strategy applied, sows consumed their daily ration in a single visit accounting for only 18% of the visits to the automatic feeders. In contrast, 92% of the visits to the drinking troughs were devoted to drinking. The economic and environmental long-term benefits of precision feeding are nuanced when compared to the conventional feeding, depending on how this latter strategy is applied.

The effect of ambient temperature (T; 12 to 22 °C) and body weight (BW; 37 to 95 kg) on metabolisable energy intake (ME) and the components of energy balance was studied in six individually-housed barrows kept in a respiratory chamber. Each animal was fed ad libitum and was exposed successively in a cyclic manner to variable T (three days per T). The O$_2$ and CO$_2$ concentrations, feed intake and physical activity were continuously recorded and used to calculate total heat production (HP), heat production due to physical activity (HP$_{{\rm act}}$) and the short-term thermic effect of feed (TEF$_{{\rm st}}$). The HP and its components were modelled using non-linear equations with T, BW and ME as predictors. The results were compared to predicted values from the equations obtained in a previous experiment performed on group-housed pigs. Data indicate that adaptations of individually-housed pigs under cold exposure are more extreme when compared to group-housed animals, especially with respect to the marked increase of energy intake and physical activity. The contribution of HP$_{{\rm act}}$ to HP was on average 17 and 23% at 22 and 12 °C, respectively. Over this temperature range, the apparent efficiency of ME utilisation increased from 0.65 to 0.81. Prediction equations obtained for group-housed pigs fitted the measured HP obtained for individually-housed pigs reasonably well, which indicates that the former can be used to model energy utilisation irrespective of housing conditions (individual vs. group) when differences in feed intake under cold exposure are considered.