Relationships between gilt development and herd production efficiency are revealed by simulation

The gilt development level is a critical factor for profitability in the pig industry. To evaluate the impact of different gilt development levels on the age structure and production efficiency of female herds we used the performance data of a pig farm that was simulated over a ten-year period, with current production statistics from the Chinese pig industry as a basis for the model. In a herd of 600 breeding sows, we compared age structure, number born alive (NBA), longevity and sow lifetime productivity in three scenarios with gilt culling rates of 10%, 20%, and 30%. The results show that the gilt development has no significant effects on the age structure. The gilt development had no significant effects either on sow reproductive performance or production efficiency. However, the annual replacement rate, longevity, and sow lifetime productivity varied significantly in the three levels of gilt development (P < 0.01). We conclude that the gilt development is closely related to herd turnover and reproductive performance, and ultimately affects the cost of pig production. Gilt development is, therefore, an extremely important factor in an integrated pig production system.