Summary
Canadian pigs are getting heavier. Average carcass weight rose from 86 kg in 1999 to over 103 kg in 2019. This creates a challenge: how do you fairly compare pigs that were measured at very different weights and ages? Researchers from the Canadian Centre for Swine Improvement (CCSI) and Quebec's swine development centre worked with nearly 2,000 purebred Duroc, Yorkshire, and Landrace pigs across 13 farm trials. They measured weight, backfat, muscle depth, and intramuscular fat repeatedly as pigs grew from 30 to 160 kg. The team tested several mathematical models to predict what a pig's measurements would look like at a standard weight. A curved growth model (the Gompertz equation) outperformed older, straight-line methods, especially for heavier pigs. They also introduced a machine learning approach that improves its predictions over time as more data is collected.