Use of Porcine Luteinizing Hormone at Oestrous Onset in a Protocol for Fixed‐Time Artificial Insemination in Gilts

Abstract

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.

Porcine luteinising hormone given at oestrus onset by intramuscular route does not advance ovulation in gilts

“…Considering that the onset of LH surge can start seven hours before oestrous detection in gilts submitted to hormonal induction with eCG and pLH (DEGENSTEIN et al, 2008) and that the natural LH surge in sows can start five hours before oestrus detection (SOEDE et al, 1994), the application of pLH at oestrous onset could be too late to advance ovulation. Studies that showed a reduction in the interval pLH application and ovulation did not observe any effect on oestrus duration (DEGENSTEIN et al , 2008;ULGUIM et al, 2014), similar to results observed in this study. In conclusion, the use of 2.5mg or 5mg of pLH given at oestrus onset in gilts does not advance and synchronise the interval between the onset of oestrus and ovulation.…”

“…route at oestrus onset in weaned sows submitted to oestrus detection once a day. However, ULGUIM et al (2014) showed that the use of 2.5mg of pLH by vulvar submucosal route at oestrous onset in pubertal gilts submitted to oestrus detection twice a day reduced the interval from pLH application to ovulation (32.3±1.4h) compared to gilts with no ovulation induction at oestrous onset (34.7±1.4h). In the same study, the application of 5mg of pLH by i.m.…”

“…According to ULGUIM et al (2014), the frequency of sows ovulated up to 24h after 5mg pLH by the i.m. route (31.4%) did not differ compared to gilts that did not receive any pLH application (25.5%).…”

Fixed‐time post‐cervical artificial insemination in weaned sows following buserelin use combined with/without eCG

“…Gonadotropin‐releasing hormone (GnRH) analogues or LH/hCG (luteinising hormone/human chorionic gonadotropin) have been efficiently used to induce ovulation in weaned sows (Kirkwood & Kauffold, ). FTAI protocols following the use of porcine LH (pLH), in combination with equine chorionic gonadotropin (eCG) at weaning (Bennet‐Steward, Aramini, Pelland, & Friendship, ; Cassar, Kirkwood, Poljik, Bennett‐Steward, & Friendship, ) or a single pLH application at the onset of oestrus, have been proposed for weaned sows (Fontana et al., ; Ulguim et al., ; Zak et al., ). Several GnRH agonists, such as goserelin (Brüssow et al., ), licerelin (Fries et al., ), buserelin (Driancourt et al., ; Martinat‐Botté, Venturi, Guillouet, Driancourt, & Terqui, ; Möller‐Holtkamp, Stickan, Parvizi, & Elsaesse, ) and triptorelin (Knox et al., ; Taibl, Breen, Webel, & Know, ) are effective for advancing the ovulation time.…”

Factors affecting estrus and ovulation time in weaned sows with induced ovulation by GnRH administration in different seasons

“…Earlier protocols induced both follicle development and ovulation time (e.g. using eCG after weaning and hCG 72–84 hr later) [5], but lately, protocols that use only GnRH [1, 10, 12] or LH agonist have been developed [6, 31]. These products are administered at a fixed time from weaning [1, 6] or from estrus [12, 31].…”