The Effects of Different Caffeine Concentration Levels and Warming Durations on the Quality of Boar Semen after 3 Days of Storage

The objective of this study was to investigate the effects of caffeine concentration and semen warming duration on semen quality in boar semen. Semen was collected from four boars, with three ejaculates per boar. The semen was diluted using Beltsville Thawing Solution (BTS) and stored at 17°C for three days. The experiment was designed as a factorial in a randomized complete block design (RCBD), with two factors: caffeine concentrations (0, 10, and 100 µg/mL) and semen warming durations at 37°C (5, 15, and 30 minutes). Semen quality was evaluated based on motility, abnormality, and kinematic parameters. The results revealed a significant interaction between caffeine concentration and warming duration on progressive motility and proximal droplet abnormalities (P<0.05). The highest percentages of progressive motility and proximal droplet abnormalities were observed in the group supplemented with 100 µg/mL of caffeine (P<0.05). Warming semen for 15 minutes significantly increased values of progressive motility, DMR, and proximal droplet abnormalities (P<0.05), whereas warming for 5 minutes yielded the highest motility (P<0.05). For kinematic parameters, warming duration had a significant effect on Straightness (STR), Linearity (LIN), Beat Cross Frequency (BCF), and Wobble (WOB) (P<0.05). Specifically, warming for 15 and 30 minutes resulted in higher STR and BCF values compared to 5 minutes, while LIN was highest at 15 minutes, and WOB was highest at 30 minutes (P<0.05). Regarding caffeine concentration alone, 100 µg/mL significantly increased proximal droplet abnormalities and Amplitude of Lateral Head Displacement (ALH), whereas 0 µg/mL resulted in the highest BCF value (P<0.05).