Researchers from Western Sydney University in Australia have found a new non-invasive way to detect pregnancy in Merino sheep through the analysis of reproductive hormones in wool.
The study, supervised by Edward Narayan from the university’s School of Science & Health and Stress Lab, tested wool steroid hormone levels of cortisol and progesterone in a sample of 46 maiden Merino ewes throughout 2017 and compared their levels during pregnancy to determine how wool-derived hormones vary.
“The study represents the first long-term assessment of cortisol and progesterone levels in Merino ewes using wool as a non-invasive hormone assessment tool,” Narayan said.
The results of this study correlated with steroid hormone measurements from traditional testing using blood plasma, supporting wool as a non-invasive alternative assessment tool for reproductive hormone measurement, the university said.
“Pregnancy in Merino ewes elicited significant increases in wool progesterone and cortisol levels. While the progesterone levels decreased significantly after birth, cortisol levels did not. This was an interesting finding as analyses of long-term changes in cortisol levels in sheep have been difficult to obtain through blood samples, as they change at a minute scale,” Narayan explained.
“This field of research is very new and works off the basis that blood-borne steroid hormones are slowly incorporated into the emerging wool shaft and slowly grow out with it, reflecting the steroid level over the growth period for that sample,” he added.
The findings of the study are a positive step toward the introduction of wool-based reproductive testing in ewes on the farm, potentially replacing other currently used invasive and expensive techniques that provide only a snapshot of hormone levels at the time of sampling.
“We see potential in this new measurement tool for better research, where the measurement of reproduction hormones stored in the wool fiber has less impact on the sheep being studied, can reduce the cost of research and can reduce the complexity of the research,” said Dr. Jane Littlejohn, general manager of research for Australian Wool Innovation, Australia's research and marketing body for its wool industry.
The research was published in PLOS ONE.