Evaluation of two qualitative enzyme immunoassays for the rapid assessment of progesterone in equine plasma.

The research focuses on evaluating two types of qualitative enzyme immunoassays for swiftly assessing progesterone levels in equine plasma to determine the functionality of the corpus luteum during a mare’s estrous cycle.

Background and Importance of the Study

• The research is rooted in understanding the fluctuation of progesterone levels during a mare’s estrous cycle. Progesterone is low during estrus, increases rapidly after ovulation, and remains high during diestrus, later decreasing to reach basal levels by day 16 or 17.
• Progesterone level is significant in assessing the presence or absence of a functional corpus luteum. Rapid and precise progesterone assays can assist in determining ovulation, confirming estrus, and identifying erratic cycles, making this study important for equine reproductive management.

Current Practices and Limitations

• The operational procedures to check the corpus luteum include digital transrectal examination and ultrasonography, but they do not indicate the corpus luteum’s functionality. They often necessitate re-examinations or estrus inductions due to the absence of a rapid progesterone assay.
• Hitherto, most studies engaged radioimmunoassay (RIA) techniques to determine blood progesterone concentrations. Although precise and sensitive, these techniques are elaborate and necessitate a radioactive-material-handler laboratory.
• An alternative is the enzyme-linked immunosorbent assays (ELISA) that yield similar results to RIA. Although they are suitable for laboratory work, they are not practical for use on the farm due to the time and equipment needed, and the cost of evaluating small batches of samples.

Aim and Methodology

• The study’s objective is to evaluate two types of qualitative ELISA kits that can expediently distinguish between high and low progesterone content during early diestrus.
• The two kits under evaluation were selected for their accessibility and usage in current veterinary practices, with one being designed for progesterone determination in bitches, and the other for progesterone determination in cow’s milk.