NAICS 11221 includes farrow-to-finish operations, feeder pig producers, and breeding stock farms. Contract production arrangements — where a packer or integrator owns the animals and a farmer provides housing and labor — are also counted here, reflecting the vertically integrated structure of the modern US pork industry.

When domestic herd inventories are high and processing capacity is fully utilized, import demand for live swine and pork products tends to be lower. Conversely, disease outbreaks or feed cost shocks that reduce domestic production can create openings for import substitution, making subsector production data a useful leading indicator for trade flow analysis.