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Identifying the reproductive status of replacement gilts at the appropriate age can improve mating efficiency and reduce non-productive days.
Objective: This study aimed to evaluate the reproductive status of gilts and assess the accuracy of a serum progesterone strip test.
Methods: A total of 112 Landrace × Yorkshire gilts, aged 196–238 days, were enrolled. Estrus detection was performed daily from 189 days of age using the back-pressure test with fence-line boar exposure. Blood samples were collected from all gilts, and serum progesterone levels were determined using both ELISA and a progesterone lateral flow assays (LFAs) strip test. Puberty was defined by an ELISA-based serum progesterone concentration ≥5.0 ng/ml. The LFAs employed a competitive assay using a monoclonal antibody against progesterone. A single test line indicated a ‘positive’ result (pubertal), while two lines indicated ‘negative’ (prepubertal). To perform the test, 2–3 drops of serum were applied to the strip, with results read after 15 min.
Results: Based on ELISA, 51.8 % of gilts were pubertal and 48.2 % were prepubertal. Pubertal gilts had significantly higher serum progesterone levels than prepubertal gilts (30.8 ± 11.4 vs. 0.8 ± 0.8 ng/ml). The LFAs correctly identified 98.2 % of pubertal gilts and 94.4 % of prepubertal gilts, yielding a sensitivity of 98.2 % and specificity of 94.4 %.
Conclusion: The progesterone strip test demonstrated high accuracy and shows strong potential for on-farm use in identifying pubertal gilts based on serum progesterone concentration.
Taechamaeteekul P, Pimpitak u, Suwimonteerabutr J, Poonlapdecha W, Khun-arwut N, Komolpis K, Rengpipat S, Sang-Gassanee K, Lin H, Collell M, Knox RV, Tummaruk P. The use of the serum progesterone strip test as a clinical tool for assessing reproductive status in replacement gilts. Theriogenology, Volume 248, 2025, 117627, ISSN 0093-691X. https://doi.org/10.1016/j.theriogenology.2025.117627
