Progesterone level can be used to determine precise moment of the reproductive cycle in gilts/ sows. Reproductive cycle has a folicular and luteal phase (high levels of progesterone). During luteal phase, progesterone level increases until day 12-14 when the luteal corpus (LC) become sensitive to PGF2α and progesterone level decreases in 48h just until the next estrus. Prepuberty gilts just around heat, have very low progesterone levels; 24-48h post-heat progesterone levels are high and remain high for at least 15-18 days indicating LC presence; finally 24-48h prior to heat progesterone levels drop very quickly again. The objective of this study is to demonstrate under field conditions how a commercial kit Ovu-check® can help establish whether a group of gilts that have not manifested consistent heat symptoms had cycled or not.
