The Impact of Evaporative Pad Cooling on Finishing Pig Performance

The objective was to evaluate finishing pig performance between barns with either natural ventilation (NATURAL; n=4), tunnel ventilation (TUNNEL; n=3) or tunnel ventilation with cool cell pads (COOLCELL; n=2). located on the same farm in southeast North Carolina. Each barn was curtain sided, 12.5 m wide, 45.5 m long with fully slatted flooring. All TUNNEL and COOLCELL barns were equipped with four 1.2 m and one 0.9 m fans on the east end. Both COOLCELL barns contained two cool cell pads (each 1.2 m x 9.2 m) on the west end. Cool cell pads operated daily from 9am to 9pm when temperatures reached a set point (26.5 to 29.0 ^oC) that varied according to pig size. Pig performance was assessed from 2013 through 2016. Traits included ADG, feed efficiency (F:G), percent livability (LIVABILITY), percent culls (CULLS) and medication costs per pig (MEDS). Seasons were defined as pigs marketed during summer (SUMMER; n=31) or nonsummer months (NONSUMMER; n=41). Average pig start and end weight were 23.6±3.7 and 125.3±9.3 kg, respectively. Data was analyzed in SAS using PROC MIXED with fixed effects of year, season, barn type and barn type × season interaction and a random effect of pig source. Pig start weight was included as a covariate for F:G and MEDS. Barn was the experimental unit. Pigs in TUNNEL and COOLCELL barns had greater (P<0.05) ADG than those in NATURAL barns (820 and 817 vs. 793 g, respectively). Between seasons, ADG tended (P=0.09) to be reduced in SUMMER vs. NONSUMMER (820 vs. 800 g). Barn F:G was improved (P<0.01) in SUMMER when compared to NONSUMMER (2.60 vs. 2.71). Livability was greater (P<0.05) in SUMMER compared to NONSUMMER (93.8 vs. 92.0%). Similarly, CULLS were lower (P<0.05) during SUMMER vs. NONSUMMER (3.0 vs. 4.0%). There was a barn type by season interaction (P<0.05) for MEDS. Barn MEDS were similar (P>0.05) across barn types during NONSUMMER. Yet during SUMMER, MEDS were higher (P<0.05) for TUNNEL when compared to NATURAL or COOLCELL ($2.17 vs. $1.91 and $1.77 per pig, respectively). By season, MEDS were reduced (P<0.01) in SUMMER when compared to NONSUMMER ($1.95 vs. $2.42 per pig). An increase in pig start weight lowered (P<0.01) MEDS. Results suggest no pig performance differences between TUNNEL and COOLCELL. Yet pigs from both TUNNEL and COOLCELL grew faster than NATURAL.