VS2.5FTAI – 2.5 mg pLH by the vulvar submucosal route at oestrous onset and a single FTAI 16 h
later; IM5FTAI – 5 mg pLH by the intramuscular route at oestrous onset and a single FTAI 16 h later. More VS2.5FTAI
gilts (47.1%; p < 0.05) ovulated within 24 h after oestrous
onset than control gilts (25.5%) whereas IM5FTAI gilts had
an intermediate percentage (31.4%; p > 0.05). The IOEO
tended to be shorter (p = 0.06) in VS2.5FTAI (30.2 1.4 h)
than in control (34.7 1.4 h) gilts, but there was no difference
(p > 0.05) between control and IM5FTAI (32.8 1.4 h) gilts.
Farrowing rate was not different (p > 0.05) among treatments.
Total born piglets (TB) was lower (p < 0.05) in VS2.5FTAI
(12.3 0.4) than in control gilts (14.1 0.4), whereas intermediate
TB was observed in IM5FTAI gilts (13.3 0.4). Due
to the advancement of ovulation, reduction of the hormonal
dose and the ease of application, the vulvar submucosal route
would be the best option for FTAI protocols, but their
negative impact on litter size remains to be elucidated. Taking
into account the good fertility results obtained in IM5FTAI
gilts whose ovulation was not advanced, the possibility of a
single FTAI without any hormonal treatment should be
further investigated, to establish reliable FTAI protocols for
gilts.