Mean ( SEM) numbers of transferable embryos were higher when the P4 device was removed at 36 h and pLH was administered at 60 h after the first PGF (P36LH60 6.3 1.4) compared to other treatments (P24LH60 3.7 1.1; P24LH48 2.4 0.8; or P36LH48 2.2 0.7).