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

Abstract

In order to efficiently have a consistent supply of service-ready gilts available to incorporate into each batch of breeding sows, it is necessary to manipulate the timing of estrus and possibly the timing of ovulation of gilts. Estrus can be synchronized by the withdrawal of altrenogest after at least 14 days of treatment. It is possible that protocols developed to induce ovulation, and therefore allow fixed-time artificial insemination (FTAI), can improve the predictability of gilt breeding. This study investigated the effect of two FTAI protocols in gilts on reproductive performance and timing of farrowing and piglet weaning weight compared to gilts bred based on signs of estrus after cessation of altrenogest. Puberty was induced in gilts, followed by treatment with altrenogest. Following altrenogest withdrawal, 180 gilts were assigned to one of three treatment groups. Group 1 gilts (LUT, n = 62) were treated with 600 IU equine chorionic gonadotropin 24 h after altrenogest withdrawal and 5 mg porcine luteinizing hormone (pLH) 80 h later, followed by a single FTAI 36 h after pLH. Group 2 gilts (TRI, n= 61) received 2 mL of a gonadotropin-releasing hormone agonist, triptorelin acetate, intravaginally 6 d after altrenogest withdrawal and were bred by a single FTAI 24 h later. Group 3 gilts (CON, n = 57) were observed for estrus and bred twice by AI, 24 h apart. LUT and TRI gilts farrowed closer together (2.4 ± 1.6 and 2.9 ± 1.2 d(days), respectively) compared to CON gilts (4.5 ± 3.3 d). Piglets in LUT were 80 g (p < 0.001) heavier and piglets in TRI were 64 g (p < 0.05) heavier at weaning than CON piglets, when controlling for birth weight. Results indicate that FTAI might be useful as a means of minimizing the time from the first to the last gilt farrowing in a breeding batch of gilts. However, modifications of the protocols may be required to ensure optimum farrowing rates and litter size.

Single Fixed-Time Post-Cervical Insemination in Gilts with Buserelin

“…Therefore, farrowing would be expected to be grouped in a short period. The advantages of all sows farrowing close together includes improved labour efficiency in the farrowing room due to easier cross-fostering, better supervision of farrowing, and efficient processing of litters [15,24]. Our results showed a significant effect of season on delivery batch duration, with shorter values in autumn.…”

“…The use of 100-400 µg triptorelin with FTAI in gilts at 120 h after Regumate treatment obtained great results for ovulation induction, but the optimal timing of triptorelin administration after Regumate protocol might not yet have been identified in gilts [22]. In contrast, a single FTAI-CAI triptorelin protocol applied 120 h after Regumate treatment in gilts showed a farrowing rate lower than in the control group (80.3% versus 89.5%) [24]. Future research must be conducted using FTAI triptorelin protocols in gilts.…”

“…This reduction in cost and labour of hormonal protocols could ease single FTAI use in routine AI protocols in gilts. Rodrigues [24] compared two different protocols to synchronize ovulation before FTAI-CAI (eCG vs. Triptorelin acetate) in gilts from an experimental farm; these protocols were based on procedures previously used in multiparous sows, and farrowing rates and litter sizes were lower than those obtained with the current AI technique. Therefore, more research is needed for the establishment of new protocols to improve reproductive performance in gilts, considering the differences between farms.…”

Erratum: Rodrigues, L.; Amezcua, R.; Cassar, G.; O’Sullivan, T.; Friendship, R. Comparison of Single, Fixed-Time Artificial Insemination in Gilts Using Two Different Protocols to Synchronize Ovulation. Animals 2020, 10, 306

“…The authors wish to make the following corrections to their paper [1]: The heading "Conclusions" should be inserted before the final paragraph of the Discussion. The following citations in the 'Discussion' should be changed: In the Discussion, in the paragraph which begins with 'Ultrasound assessment', a new citation, [10], should be inserted after the following sentence: The ovulation results of the present study are similar to those of other studies.…”

PMSG Pretreatment Before Fixed-Time Artificial Insemination Improves the Reproductive Performance in Replacement Gilts

“…Vangroenweghe found that the estrus rate and birth weight of piglets signi cantly improved after treatment of gilts with ALT and GnRH analogs; however, the litter size was not affected [8] . In a recent study, after discontinuation of ALT treatment, eCG and Porcine luteinizing hormone (pLH) intramuscular injection in gilts resulted in shorter delivery time; however, it resulted in a lower litter size than that of the control group [9] .…”