An Exploration of Current and Perspective Semen Analysis and Sperm Selection for Livestock Artificial Insemination

Abstract

Artificial insemination of livestock has been a staple technology for producers worldwide for over sixty years. This reproductive technology has allowed for the rapid improvement of livestock genetics, most notably in dairy cattle and pigs. This field has experienced continuous improvements over the last six decades. Though much work has been carried out to improve the efficiency of AI, there are still many areas which continue to experience improvement, including semen analysis procedures, sperm selection techniques, sperm sexing technologies, and semen storage methods. Additionally, the use of AI continues to grow in beef cattle, horses, and small ruminants as the technology continues to become more efficient and yield higher pregnancy rates. In this review, AI trends in the various livestock species as well as cutting edge improvements in the aforementioned areas will be discussed at length. Future work will continue to refine the protocols which are used for AI and continue to increase pregnancy rates within all livestock species.

Keywords: artificial insemination; livestock andrology; semen analysis; semen storage; sperm selecting; sperm sexing.

Figure 1

Biomarker sperm neural network training example. Images reflecting the biomarker status such as plasma membrane integrity (detected by propidium iodide), acrosome integrity (detected by lectin PNA conjugated to Cy5), and the sperm zinc signature (detected by FluoZin™-3 AM, ThermoFisher Scientific, Waltham, MA, USA) could be used to train neural networks to detect the percent of fertile and infertile sperm in a sample.