Title: Multi-level mixed-effects model analysis for reproductive performance of high prolific but low longevity sows
Authors: Yuzo Koketsu - Meiji University (Japan) [presenting]
Abstract: Prolificacy and longevity are critical on commercial pig farms. Our objective was to examine the impact of piglets born alive (PBA) in parity 1 on early removal of sows from farms. The PBA groups were categorized based on the upper and lower 10th percentiles of PBA in parity 1: High-prolific, ordinary, and Low-prolific sows. Also, early removal of sows were defined as culling and death of sows in parities 1-3. Data comprised 411,360 parity records of 153,523 sows farrowed between 2011 and 2017 on 155 Spanish farms. Three-level mixed-effects models were applied to the data by using a farm at level 3, a sow at level 2 and a parity record at level 3. Removal rates by parity 3 were 27.9, 28, and 39.2\% for High-prolific, ordinary, and Low-prolific sows respectively. There were 2-way interactions between PBA groups and removal groups in farrowed sows for PBA and piglets weaned in parity 1 ($P < 0.01$). Low-prolific sows that were removed had 0.8-1.6 fewer PBA and 0.3-0.8 fewer piglets weaned than survived sows ($P < 0.05$), but there were no such differences for High-prolific sows ($P > 0.05$). In conclusion, PBA in parity 1 affects early removal of farrowed sows.