Omics approaches to understand impact of heat stress on semen quality and fertility in bovines

Abstract

Recent surge in global climate change poses unprecedented challenges to traditional livestock breeding methods. In tropical countries, where large bovines are vital source of meat and milk, the escalating global warming significantly impact their productivity. Central to this challenge is the resilient ability of the animals, which directly influences the productivity. Artificial insemination (AI) programs, a cornerstone in modern livestock production, have also been severely hampered by climate change-induced heat stress, affecting the quality semen production. This stress not only affects the blood biochemical profiles of the animals but also their testicular physiology, leading to the issues such as low-quality semen with compromised freezability and fertility. Researchers have identified specific markers, including single nucleotide polymorphisms (SNPs), copy number variations (CNV), and epigenetic signatures like histone modifications, DNA methylation, and noncoding RNAs, influencing the semen quality in livestock species. Furthermore, the issue of heat stress has been addressed in a very precise way, and biomarkers have been identified, which can be integrated into the breeding programme to keep up the sire summary. Transcriptomic studies have further illuminated the temporal expression patterns of genes related to sperm quality during heat stress, pinpointing candidate genes for further exploration. This review comprehensively summarizes the progress made in understanding the intricacies of sperm biology in bovines, with a specific focus on cattle and buffalo delving into a spectrum of changes, from biochemical shifts to profound cellular alterations, including genomic, transcriptomic, and epigenetic modifications.