Body weight development of weaned sows in relation to several feeding regimes under traditional pig keeping systems in West Papua, Indonesia, was quantified using a model. This model was developed using Simile version 4.7. Feeding diets investigated were based on local feeds as currently applied by pig farmers. Quantities of feed used were 1, 2 and 3 kg fresh matter. In the first feeding regime with 3 kg day-1 on offer, we obtained a balance of energy and quality, rich in energy rich and protein, depending on digestibility, i.e. 34.73, 32.63 and 36.39 MJ kg-1 DM and 0.62, 0.34 and 0.99 kg CP kg-1 DM. In the second feeding regime with 2 kg day-1 on offer, this was 22.69, 21.99 and 24.92 MJ kg-1 DM and 0.35, 0.26 and 0.72 kg CP kg -1 DM. The third feeding regime with 1 kg day-1 on offer contained 12.04, 11.34 and 12.46 MJ kg-1 DM energy and 0.27, 0.18 and 0.36 kg CP DM protein.
Initial body body weight at weaning was set at 87 kg. No environmental factors were incorporated in the model. Results indicated that body weight of the weaned sows’ increases when 3 kg of feeds was offered. With 2 kg, feed maintenance requirement can be met and with less than 2 kg body weight loss occured. One kg of feed on offer daily gives negative impact resulting in starvation and loss of body weight. The insufficient feed intake can induce a negative impact on stimulating production of reproduction hormones, i.e. LH and FSH which are needed to induce ovum shed in oviduct. This is at risk when weaned sows enter the mating season and gestating period and receiving this low feed diet. In conclusion, considering environmental factors can improve simulation of feed intake and deposited protein and fat. Simulation of the entire sow reproduction and production life cycle becomes priority.