PSI-9 Evaluation of an Electronically-controlled Floor Cooling Pad on Semen Quality in Boars During Moderate Heat Stress

Abstract

Abstract Heat stress (HS) decreases semen quality and production in boars. Therefore, the study objective was to evaluate the use of electronically-controlled cooling pads to reduce the negative effects of HS on semen quality. Boars (n=24) were randomly allotted to two treatment groups: boars housed on a non-functional cooling pad (CON) or pads flushing water every 8 minutes or when the pad reached 28.5°C (FLUSH). For 3 d, boars were subjected to cyclical HS (28 to 32°C; >50% relative humidity). Semen was collected for 7 weeks (2 weeks prior to determine baseline semen parameters, the day after HS, and weekly for 4 weeks post HS), and evaluated for volume, sperm concentration, motility, progressive motility, morphology, viability, and kinematic motion parameters. FLUSH boars had higher semen volumes compared to CON (P=0.011) without a corresponding increase in total sperm produced (P=0.852). Boars in FLUSH had higher motility in all weeks (87.0–90.8%) when compared to CON boars. FLUSH boars had higher motility starting in week 4 after HS compared to CON (P=0.017). No differences in progressive motility or kinematic motion parameters were found. There was a tendency for FLUSH boars to have a higher percent normal morphology compared to CON boars (83.1 vs 77.5%, P=0.083) resulting from decreased proximal and distal droplets in the FLUSH boars (P=0.029 and P=.0014, respectively). During week 2 post HS, there was a tendency for FLUSH boars to have a lower percentage of non-viable cells compared to all other weeks for FLUSH and CON boars (P=0.088). Cooling pads were effective at reducing the negative impacts of HS on semen volume, motility, and morphological abnormalities.