Impact of Climate Change on Semen Quality and Fertility of Bull

Abstract

Male fertility is impacted by heat stress in a complicated and multifaceted pathway. Unfavourable climatic conditions can modify the complex regulatory systems that the testes and scrotum can protect developing sperm during their most vulnerable stages. Testicular heat stress has a negative correlation with sperm quality and fertility. It can alter morphology, viability, motility, and the ability of spermatozoa to fertilise. High temperature interferes with the oxidative metabolism of glucose in spermatic cells which resulting in mitochondrial dysfunctions. This adverse effect produces reactive oxygen species on sperm DNA and also affects antioxidant production, which generally protects sperm from oxidative attacks, resulting in derangement of the spermatogenesis process and epididymal dysfunction. This dysfunction leads to the development of abnormal and dead spermatozoa, which adversely affects the fertility of the bull. This review aimed to assess the early sequential effects of heat stress and impacts of climate change on semen quality and on the mechanisms leading to defective sperm production.