Anecdotal observations suggest that pigs get fatter at certain times of the year. Abattoir data from a major Western Australian genotype were investigated to determine whether there is seasonal variation in P2, and if so, what factors may contribute to this. In the data collected, it was found that pigs were fattest during spring and leanest during autumn. At initial observation, variation in carcass weight ( hence liveweight at slaughter) appeared to explain much of the variation in carcass fatness. However, fitting a linear mixed model to the P2 data, adjusted for carcass weight, indicated that there was also a significant effect of season on carcass quality.
Trezona, M., Mullan, B. P., Antuono, M. D., Wilson, R. H., & Williams, I. (2004). The causes of seasonal variation in backfat thickness of pigs in Western Australia. Australian Journal of Agricultural Research, 55(3), 273-277. https://doi.org/10.1071/AR03029