Infrared thermography as a noninvasive method to assess scrotal insulation on sperm production in beef bulls

This study evaluated the thermoregulation and spermatogenic changes by scrotal temperature gradient using infrared thermography in testicular compromised bulls. Bulls were insulated (n=6) for 72hr and control animals (n=3) remained without insulation during all the experimental period. Seminal evaluation was performed prior, at insult removal and once per week for 13 consecutive weeks. Mean temperature gradient in insulated animals was lower at the time of insulation removal compared to the week prior and after the insult (p<.05). Two weeks after insult, sperm motility was lower in insulated compared to control animals (p<.01) and spermatozoa total defects were higher in insulated compared to control animals (p<.05). Two and seven weeks after insult, the major defects were higher in insulated compared to control animals (p<.05). Scrotal temperature gradient showed a positive correlation with sperm mass motion (p<.01) and a negative correlation with ocular globe temperature (p<.01) in insulated animals. The infrared thermography can be used to evaluate ocular globe temperature in bulls; however, it is only effective to detect changes in scrotal temperature gradient at the insult removal.