National Air Emissions Monitoring Study (NAEMS) Sow Site NC4B: Observations of Farm Operation and Management.

The NAEMS provides a unique opportunity to continuously observe individual animal confined feeding operations over long periods. Information is presented on operation and management of a representative sow gestation and farrowing farm in eastern North Carolina. Approximately 2200 pigs are on site in three barns: breeding/gestation (~900), gestation (~900), and farrowing (~320; 16 rooms; 20 sows/room). Sows weigh ~140 to 230 kg and farrow an average of 10 piglets/sow. Piglets grow to 6.4 kg from a birth weight of 1.2 kg in 21 days; 800 to 1000 piglets are shipped weekly. A single feed formulation (~ 2.2% N) is provided once daily to pregnant sows. Lactating sows are fed a 3.3% N diet 4x daily. All three barns are force ventilated. Default duty cycle is 10 min. for stage 1 fans, till overridden by the difference between internal and exterior temperature. Air is pulled into the farrowing rooms via controlled baffles distributed along the sidewalls (2 46-cm and 1 61-cm variable-speed fans). The breeding/gestation barn uses endwall exhaust fans (122-cm dia., 12 total) that draw air through evaporative cooling pads in the center. The gestation barn uses conventional tunnel-ventilation (8 122-cm dia. fans) with adjustable endwall curtain. Waste is handled through shallow pits (3 pits per breeding and gestation barns, 2 per farrowing room; ~48 cm from animal floor to bottom of the pit). The pit is drained (pull-plug) every 7 – 10 days, then flushed and filled with liquid from the anaerobic lagoon. Pit sludge depth varies along the length of the barn and undoubtedly with age. Presence of sludge in the pits over half the length of the breeding and gestation barns represents a potential source of ammonia and hydrogen sulfide emissions in excess of that from fresh urine and fecal matter and weekly renewal of lagoon liquid.