Authors : S. D. Kharde, S. D. Ingole and S. V. Bharucha
Page Nos : 132-140
Description :
This study evaluated seasonal thermal stress impacts on thermoregulation and semen quality in 20 Holstein Friesian crossbred bulls in Mumbai. Environmental conditions shifted significantly from a comfortable winter temperature humidity index (THI) of 70.55 to a stressful summer THI of 80.40. Infrared thermography revealed that elevated summer heat load significantly increased systemic ocular temperatures from 97.66 to 99.33. Concurrently, localized scrotal surface temperatures rose across proximal, mid, and distal poles, while the scrotal thermal gradient narrowed from 5.14°C to 4.76°C, indicating compromised testicular thermoregulatory capacity. This thermal breakdown severely impaired summer spermatogenesis. Sperm concentration dropped from 1053.67 x 106 ml to 886.54 x 106 ml, initial motility decreased from 77.69% to 73.24%, and membrane integrity (HOST) declined from 66.76% to 56.14%. Morphological abnormalities also rose sharply from 10.96% to 16.28%. Monitoring ocular-scrotal thermal profiles provides vital insights for managing breeding bull fertility in tropical environments.
