In the breeding building, oestrous detection was carried out three times a day (7 a.m., 3 p.m. and 11 p.m.)
through fenceline boar contact and back pressure test. At breeding oestrus, trios of gilts were formed according
to age, weight and number of oestrous cycles and were assigned to the following groups: control – without
hormonal application and inseminations at 0, 24 and 48 h after oestrous onset; VS2.5FTAI – use of 2.5 mg
pLH (Lutropin-V, Bioniche Animal Health, Belleville, ON, Canada) by the vulvar submucosal route at oestrous onset and a single FTAI 16 h later; IM5FTAI – use of 5 mg pLH by the intramuscular route at
oestrous onset and a single FTAI 16 h later. Trios were formed with gilts that showed oestrus in the same shift or no more than 8 h later. The time of insemination was
based on results of a previous pilot study in which 80%
of the gilts ovulated between 16 and 40 h after receiving
5 mg pLH at oestrous onset, by the intramuscular route
(R.R. Ulguim, unpublished data).