Contents
The aim of this study was to evaluate the effect of porcine
luteinizing hormone (pLH) given at oestrous onset in gilts, by
different routes and doses, on the interval between onset of
oestrus and ovulation (IOEO) and reproductive performance
using a single fixed-time artificial insemination (FTAI). A total
of 153 gilts were submitted to oestrous detection at 8-h
intervals and assigned to three groups: control – without
hormone application and inseminated at 0, 24 and 48 h after
oestrous onset; 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
ContentsThe aim of this study was to evaluate the effect of porcineluteinizing hormone (pLH) given at oestrous onset in gilts, bydifferent routes and doses, on the interval between onset ofoestrus and ovulation (IOEO) and reproductive performanceusing a single fixed-time artificial insemination (FTAI). A totalof 153 gilts were submitted to oestrous detection at 8-hintervals and assigned to three groups: control – withouthormone application and inseminated at 0, 24 and 48 h afteroestrous onset; VS2.5FTAI – 2.5 mg pLH by the vulvarsubmucosal route at oestrous onset and a single FTAI 16 hlater; IM5FTAI – 5 mg pLH by the intramuscular route atoestrous onset and a single FTAI 16 h later. More VS2.5FTAIgilts (47.1%; p < 0.05) ovulated within 24 h after oestrousonset than control gilts (25.5%) whereas IM5FTAI gilts hadan intermediate percentage (31.4%; p > 0.05). The IOEOtended 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). Dueto the advancement of ovulation, reduction of the hormonaldose and the ease of application, the vulvar submucosal routewould be the best option for FTAI protocols, but theirnegative impact on litter size remains to be elucidated. Takinginto account the good fertility results obtained in IM5FTAIgilts whose ovulation was not advanced, the possibility of asingle FTAI without any hormonal treatment should befurther investigated, to establish reliable FTAI protocols forgilts
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