Artificial Reproductive technologies, such as artificial insemination (AI) are pivotal for advancing genetic improvement and productivity of the Australian sheep industry. Despite their potential, inconsistent pregnancy rates following AI, the cost involved, and welfare concerns have limited the full adoption of these technologies and remain significant obstacles. Focusing efforts on big data collection and investigating alternative methods of AI have begun to address some of these challenges faced by industry, with the ultimate goal of increasing the number of elite lambs born for industry.
In a large-scale study of over 30,000 Merino ewes and 380 sires, in-vitro semen parameters and female factors recorded during insemination were used to design a predictive model, capable of calculating the likelihood of a ewe conceiving following laparoscopic AI. The model demonstrated high precision (96%) and good accuracy (x%), now offering a practical method for screening both ewes and semen prior to AI, reducing variability and restoring confidence in the technology.
In an effort to investigate a cheaper more welfare-friendly alternative to laparoscopic AI, the limited fertility of frozen-thawed ram spermatozoa following cervical AI was investigated. Hypothesised to be related to immunological barriers, the project has unveiled a protective effect of seminal plasma proteins which could be used to supplement and restore fertility. Polymorphonuclear neutrophil assays, a cervical epithelial cell-culture assay and multiplex ELISA to quantify interleukin expression seeks to characterise the molecular interaction between ram sperm, seminal plasma and the female reproductive tract, improving sperm survival in the cervix.
These projects highlight the potential of applying advanced molecular techniques rarely seen in livestock, to overcome applied reproductive challenges faced by industry. Identifying the link between in-vitro semen assessment and fertility along with exploring ways to manipulate the female immune response with seminal plasma will help improve AI outcomes and the efficiency of reproductive technologies for the Australian sheep industry.