379 Initial evaluation of floor cooling on lactating sows under acute heat stress. (1st March 2017)

• Record Type: Journal Article
• Authors: Smith, A. J.; Cabezon, F. A.; Schinckel, A. P.; Marchant-Forde, J. N.; Johnson, J. S.; Stwalley, R. M.
• Is Part Of: Journal of animal science. Volume 95(2017)Supplement 2
• Page Start: 183
• Page End: 184
• Publication Date: 2017-03-01
• Subjects: cooling pads -- lactation -- sow; Livestock -- Periodicals; Livestock; Electronic journals; Periodicals; 636.005
• DOI: 10.2527/asasmw.2017.379
• Languages: English
• ISSNs: 0021-8812

Abstract

Abstract: The objective was to evaluate the effects of floor cooling on lactating sows under severe summer heat stress. Twelve multiparous sows were provided with a cooling pad built with an aluminum plate surface, high-density polyethylene base, and copper pipes. Treatments were randomly allotted to sows to receive a constant cool water flow of 0.00 (CONTROL; n = 5), 0.25 (LOW; n = 3), 0.55 (MEDIUM; n = 2), or 0.85 L/min (HIGH; n = 2) for 90 min. The cooling was initiated 1 h after the room reached 35°C. Respiration rates (RR), rectal temperature (RT), and skin temperature (ST; 15 cm posterior to the ear) were recorded before the trial, prior to cooling, and after 90 min of cooling. Water flow rates and inlet and outlet water temperatures were recorded 6 times (every 15 min) to calculate the heat removal (watts) after cooling initiation. In all 3 replications, treatments were randomly switched between sows. Data were analyzed using the MIXED procedure in SAS (SAS Inst. Inc., Cary, NC). Respiration rate, RT, ST, and heat removal were analyzed using repeated measures with compound symmetry covariance structure with sow as a repeated random effect. For RR, RT, and ST measurements, the model included treatment and phase (before trial, prior to cooling, and at the end of the trial) and their interactions as fixed effects and replication as a random block. For the cooling phase, heat removal model included treatment and cooling time and their interactions as fixed effects and replication as a random block. The mean room temperature and relative humidity during the trial were 35.3 ± 0.7°C and 57.8 ± 3.1%, respectively. The treatments impacted RR, RT, and ST after 90 min of cooling. At the end, mean RR were 132, 89, 71, and 31 breaths/min for the CONTROL, LOW, MEDIUM, and HIGH treatments, respectively ( P < 0.001). The mean RT and ST were 39.9 and 39.8°C, respectively, for the CONTROL; 39.5 and 39.1°C, respectively, for the LOW; 39.2 and 38.8°C, respectively, for the MEDIUM; and 39.1 and 39.2°C, respectively, for the HIGH treatments ( P < 0.001 and P = 0.079, respectively). Overall heat removal during the trial was 196.2, 278.3, and 320.7 W for the LOW, MEDIUM, and HIGH treatments, respectively ( P < 0.001). Cooling pads with MEDIUM and HIGH water flow rates reduced RR and RT in lactating sows.