Single fixed-time artificial insemination in gilts and weaned sows using pLH at estrus onset administered through vulvar submucosal route

Abstract

This study evaluated the use of a single fixed-time artificial insemination (FTAI) in gilts and weaned sows using 2.5 mg of porcine luteinizing hormone (pLH) administered through vulvar submucosal route, at the onset of estrus. In experiment 1 (Exp.1), 318 pubertal gilts were assigned to two groups: control-G-no hormonal application and artificial inseminations (AIs) at 12, 36, and 60 hours after the onset of estrus if they were still in standing estrus; and FTAI-G-use of pLH at the onset of estrus and a single FTAI 12 hours later. In experiment 2 (Exp. 2), 309 weaned sows were assigned to three groups: Control-S-no hormone application and AIs at 0, 24, and 48 hours after the onset of estrus if they were still in standing estrus; FTAI-NH-no hormone application and a single FTAI at 24 hours after the onset of estrus, and FTAI-pLH-use of pLH at the onset of estrus and a single FTAI 24 hours later. Transabdominal real time B-mode ultrasonography was performed to determine whether the insemination had been performed within 24 hours before ovulation, considered as the optimal interval. In Exp. 1, ultrasound evaluation (12-hour intervals) was carried out to determine the interval between the onset of estrus and ovulation. In both experiments, 2 × 10(9) sperm cells in 80 mL were used to perform cervical and postcervical deposition of semen in gilts and sows, respectively. Compared with control-G, FTAI-G gilts had shorter (P < 0.05) duration of estrus (57.7 vs. 61.2 hours) and interval between the onset of estrus and ovulation (36.3 vs. 42.3 hours). The adjusted farrowing rate (AFR) was lower (P < 0.05) in FTAI-G (86.0%) compared with control-G (93.5%), but total piglets born (TPB) did not differ between these groups (12.3 vs. 12.5 piglets). Within the FTAI-G group, the AFR was lower (P < 0.05) in the presence (50.0%) than in the absence (94.9%) of semen backflow during AI. Also in the FTAI-G group, the insemination outside the optimal interval reduced (P < 0.05) the TPB (10.5 vs. 12.9 piglets) in comparison with gilts inseminated within the optimal interval. In Exp. 2, there were no differences in the AFR (Control-S: 94.1%; FTAI-NH: 86.1%; FTAI-pLH: 88.0%) and TPB (Control-S: 12.8; FTAI-NH: 12.7, and FTAI-pLH: 12.0 piglets) among treatments. The presence of semen backflow reduced (P < 0.05) the TPB in FTAI-pLH and FTAI-NH sows. In the FTAI-pLH, a single insemination performed too late relative to ovulation reduced the AFR (P < 0.05) compared with sows inseminated within the optimal interval. In conclusion, 2.5-mg pLH applied at the vulvar submucosa at the onset of estrus advances the ovulation in gilts, but a single FTAI performed 12 hours later reduces the farrowing rate. A single FTAI performed at 24 hours after the onset of estrus in weaned sows does not affect their reproductive performance, regardless of pLH application.

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

“…In these groups, the farrowing rate was low for both the too late (12.5%; 2/16 and 0%; 0/3) and too early (16.7%; 2/12 and 25%; 4/16) intervals relative to the ovulation. This is in contrast with the results of other studies in which the sows were single inseminated after receiving pLH at the oestrous onset and the farrowing rate was more affected when the insemination took place too late relative to the ovulation (Fontana et al., ; Ulguim, Fontana, Bernardi, Wentz, & Bortolozzo, ). In those studies, the onset of oestrus was taken as the starting point to inseminate the females, whereas the sows of the present study were inseminated at a pre‐established time after receiving the hormones, regardless of being in oestrus or not.…”

Comparison of Single, Fixed-Time Artificial Insemination in Gilts Using Two Different Protocols to Synchronize Ovulation

“…Both FTAI groups had older and heavier pigs at weaning compared to CON pigs, which is consistent with the number of breeding dates required for each treatment group. Batch farrowing is more acceptable to most producers if they can control and maintain uniformity in lactation length and weaning weights within the batch [5]. The impact of consistent age and size at weaning results in less variation in the weights of pigs through the subsequent growing phases and reduces the need to provide special care for the under-weight pigs at weaning [5].…”

“…Batch farrowing is more acceptable to most producers if they can control and maintain uniformity in lactation length and weaning weights within the batch [5]. The impact of consistent age and size at weaning results in less variation in the weights of pigs through the subsequent growing phases and reduces the need to provide special care for the under-weight pigs at weaning [5]. Using the weaning weight range from each treatment category, we can conclude that LUT gilts achieved a narrower range of weights among piglets compared to the conventional method of breeding (CON).…”

“…Producers may be able to control the timing of estrus and ovulation through synchronization protocols, allowing for the implementation of a single fixed-time artificial insemination (FTAI) program. These programs have been shown to be successful in sows [4,5], but there are few studies that have evaluated FTAI in gilts [4,6].…”

“…In mature sows, an injection of eCG at weaning followed 3 d later with an injection of porcine luteinizing hormone (pLH) can be used to induce ovulation within 35 to 40 h and, therefore, may possibly be used in an FTAI program for gilts [10,11]. Likewise, a gonadotropin-releasing hormone (GnRH) agonist, triptorelin acetate, has also been used to induce ovulation allowing FTAI in sows [5,8], although to date this product does not have a label claim for gilts in Canada. There is a need to investigate these two FTAI methods in gilts to determine whether the use of these techniques might improve estrus and ovulation synchronization in gilts.…”