Post-cervical Artificial Insemination Research Articles

PSIII-9 Field fertility following the practice of post-cervical artificial insemination (PCAI) at multiple North American swine units

Abstract On a global scale, greater than 95% of sows are bred using artificial insemination (AI). As with most technologies, efficiencies improve over time and in the case of swine AI the industry is moving towards fewer sperm per dose in conjunction with a post-cervical deposition (PCAI). Nevertheless, little information is available stating the fertility of farms actively using PCAI. The objective of this research is to provide a retrospective report on the field fertility of multiple farms in North America utilizing PCAI. As a reference, information is provided for contemporary farms utilizing conventional AI (intra-cervical deposition in conjunction with a greater total sperm count per dose). Semen doses produced for PCAI (1.5 billion total cells in 40 mL volume) sourced from one boar stud located in Tennessee and are packaged as pooled semen in NUTRIXcell + extender. Semen was held overnight at 18°C and delivered to seven farms the next day. Semen doses produced for conventional AI (CONAI) also sourced from a single boar stud located in Michigan; packaged as pooled semen at 2.75 billion total cells in a 70 mL volume using the NUTRIXcell + extender and shipped to six farms the same day as semen production. Both PCAI and CONAI were used on 100% of gilts and multiparous sows in respective systems. Field fertility, reported as farrow rate (FAR) and mean total born (TB), is reported below for both PCAI (Table 1) and CONAI (Table 2) following use per individual farms during January 2022 to September 2023. Results suggest that PCAI can maintain acceptable levels of fertility and should enable cost savings in conjunction with increased dissemination of superior genetics.

26. The use of post-cervical artificial insemination to improve reproductive performance in sows

26. The use of post-cervical artificial insemination to improve reproductive performance in sows

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

Simple SummaryCurrent protocols for gilts recommend the deposit of two/three semen doses (2–4 × 109 sperm/dose) by cervical artificial insemination (CAI), 12–24 h after estrus detection. If ovulation were predictable, gilts could be bred only once using fixed-time artificial insemination (FTAI). Using a specific catheter makes the postcervical deposition of semen possible (PCAI). This work explored the use of combining FTAI-PCAI with buserelin in gilts. In the control group (C; n = 240), gilts were inseminated twice (8 and 12 h from estrus onset). Gilts in the treatment group (T; n = 226) received buserelin (10 μg, intramuscular) 120 h after altrenogest treatment (18 d) and one single PCAI 30–33 h after buserelin administration. No significant differences were found in reproductive and production performance between groups (p > 0.05). Piglets’ birth weight was greater in the T group (p < 0.001). Estrus duration was significantly shorter in the T group (p < 0.001). Delivery batch length significantly differed depending on the season (p < 0.05); both groups only differed significantly in spring (p = 0.018), with a shorter duration in the T group. This new FTAI-PCAI protocol with buserelin is recommended in gilts, helping with optimization of genetic diffusion, boars, and semen doses.Current protocols for gilts recommend the deposit of multiple semen doses in the cervix each 12–24 h after estrus detection. Our objectives were: (1) to determine the effect of buserelin and a single fixed-time artificial insemination using the new post-cervical artificial insemination technique (FTAI-PCAI) on reproductive and productive performance in gilts, and (2) to compare this protocol with conventional estrus detection and double PCAI without hormonal induction. In the control group (C; n = 240), gilts were inseminated twice (8 and 12 h from estrus onset). Gilts in the treatment group (T; n = 226) received buserelin (10 μg, intramuscular) 120 h after altrenogest treatment (18 d) and one single PCAI 30–33 h after buserelin administration. The groups did not differ in reproductive and production performance (p > 0.05). The T group showed greater piglet birth weight and shorter estrus duration (p < 0.001). Delivery batch length differed significantly depending on the season (p < 0.05); the shortest length corresponded to autumn. Both groups only differed significantly in spring (p = 0.018), with a shorter length in the T group. This new FTAI-PCAI protocol with buserelin is recommended in gilts, helping with optimization of genetic diffusion, boars, and semen doses.

Potential fertilizer of spermatozoa in porcine epididymal tail post-orchiectomy.

The aim of this study was to determine the potential fertilizing of spermatozoa from the epididymal tail in different periods of time post-orchiectomy (P-OQ). Therefore, the study was approached in two stages. In the first stage, the orchiectomy was performed in 30 adult pigs. The testicles were stored at 5.00 ˚C in physiological saline solution for 5, 24, 48, 72, 96 and 120 hr. The spermatozoa were obtained by backflushing the vas deferens. The spermogram and fluorometric study were performed for each sample to evaluate the exposure of phosphatidyl-serine (PS) and acrosome reaction (AR). The second stage included the fertilization test, 16 prepubertal sows were selected, after synchronizing the oestrous cycle and the post-cervical artificial insemination was performed with the refrigerated sperm samples from each P-OQ time. The percentage of live sperm remained without significant changes until 96 hr P-OQ. An increase in the percentage of spermatozoa that showed a PS exposure was observed. The premature AR was evident after 72 hr. Considering that the artificial insemination was performed ensuring a minimum number of live sperms, no significant differences were observed in the number of embryos and corpora lutea. The results indicated that pig sperm collected from the epididymal tail P-OQ and stored for 5 and up to 72 hr at 5.00 ˚C had viable characteristics and maintained their fertilization ability. However, there was an increase in the loss of phospholipid asymmetry of the plasma membrane as time increased (72 and 96 hr), therefore, sperm viability was decreased.

Reproductive performance in cervical and postcervical artificial insemination (PCAI) with liquid boar semen in Gunghroo × Hampshire crossbreed pig in Nagaland

Genetic advancement for the modern swine industry is primarily accomplished through the use of reproductive biotechnology, mainly artificial insemination (AI). The objective of the present study was to compare the fertility outcome by cervical and post-cervical artificial insemination (PCAI) using normal (three billion) and reduced (one billion) number of spermatozoa in pig. Pluriparous weaned sows were grouped into 4 groups, i.e. Group- 1, AI with three billion spermatozoa by intra-cervical insemination; Group-2, AI with one and half billion spermatozoa by intra-cervical insemination; Group-3, AI with three billion spermatozoa by PCAI and Group-4, AI with one and half billion spermatozoa by PCAI. Non-significantly higher farrowing rate was recorded in Group-3 compared to Group-1. Post-cervical AI with lower number of spermatozoa (Group-4) resulted into farrowing rate which was similar to cervical insemination with higher number of spermatozoa (Group-1). There was significant difference in litter size at birth and litter size at weaning between Group-1 and 2. Litter size at birth and litter size at weaning was significantly higher in Group-4 compared to Group-2. Also, litter size at birth and litter size at weaning was significantly higher in PCAI animals (Group-2 and 4) compared to cervical inseminated animals (Group-1 and 2). In conclusion, PCAI with liquid boar semen was found to have improved farrowing rate, litter size at birth and litter size at weaning compared to cervical insemination.

Seminal Plasma Induces Overexpression of Genes Associated with Embryo Development and Implantation in Day-6 Porcine Blastocysts.

The infusion of boar seminal plasma (SP) before artificial insemination (AI) positively alters the expression of endometrial genes and pathways involved in embryo development. This study aimed to determine which transcriptome changes occur in preimplantation embryos in response to SP infusions during estrus. Postweaning estrus sows received 40-mL intrauterine infusions of either SP (N = 6) or BTS extender (control group; N = 6) 30 min before each of two post-cervical AIs. On Day 6, embryos were surgically collected and analyzed for differential gene expression. Microarray analysis of embryos revealed 210 annotated genes, differentially expressed (p-value < 0.05 and fold change </> 2) in SP-blastocysts, compared to controls. Most of these genes were associated with biological, cellular, metabolic and developmental processes. The pathways enriched among the upregulated genes related to signal transduction, cellular processes and the endocrine system. Among altered genes involved in these pathways, the SP-group showed a conspicuous overexpression of ApoA-I, CDK1, MAPK1, SMAD2, PRKAA1 and RICTOR, with reported key roles in embryo development, implantation, or progression of pregnancy. In conclusion, the results demonstrate that SP infusions prior to AI upregulates the expression of embryo development related genes in Day 6 pig embryos.

Seminal Plasma Modifies the Transcriptional Pattern of the Endometrium and Advances Embryo Development in Pigs.

Background: Seminal plasma (SP) promotes sperm survival and fertilizing capacity, and potentially affects embryo development, presumably via specific signaling pathways to the internal female genital tract.Objectives: This study evaluated how heterologous SP, infused immediately before postcervical artificial insemination (AI) affected embryo development and the transcriptional pattern of the pig endometria containing embryos.Materials and Methods: Postweaning estrus sows (n = 34) received 40-mL intrauterine infusions of either heterologous pooled SP or Beltsville Thawing Solution (BTS; control) 30 min before AI of semen extended to 10% of homologous SP. Embryos (all sows) and endometrium samples (3 sows/group) were removed during laparotomy 6 days after the infusion of SP or BTS to morphologically evaluate the embryos to determine their developmental stage and to analyze the endometrial transcriptome using microarrays (PORGENE 1.0 ST GeneChip array, Affymetrix) followed by qPCR for further validation.Results: Embryo viability was equal between the groups (~93%), but embryo development was significantly (P < 0.05) more advanced in the SP-treated group compared to control. A total of 1,604 endometrium transcripts were differentially expressed in the SP group compared to the control group. An enrichment analysis showed an overrepresentation of genes and pathways associated with the immune response, cytokine signaling, cell cycle, cell adhesion, and hormone response, among others.Conclusions: SP infusions prior to AI positively impacted the preimplantation embryo development and altered the expression of the endometrial genes and pathways potentially involved in embryo development.

Effect of boar seminal dose type (cervical compared with post-cervical insemination) on cooling curve, sperm quality and storage time

Seminal doses used for cervical and post-cervical artificial insemination (CAI and PCAI, respectively) vary in volume, the number of spermatozoa and packaging. The aim was to evaluate the outcomes when there was use of routine processing procedures for CAI- and PCAI-doses. Two different types of seminal doses were processed: 1) CAI: 2.7 × 109 sperm/80 ml; 2) PCAI: 1.5 × 109 sperm/45 ml. In Experiment 1, the cooling curve of seminal doses during processing occurred in two phases: 1st) At room temperature (23.4 ± 0.5 °C) from 0 (just after packaging) to 120 min; 2nd) At refrigeration (15.7 ± 0.8 °C) from 121−240 min. For the PCAI-doses, the time required to reach room temperature was 47 min compared to 107 min for CAI-doses (decreasing velocity of 0.093 °C/min and 0.048 °C/min, respectively). During refrigeration, for the PCAI-doses the time required to reach the desired preservation temperature was 20 min less than for CAI-doses (PCAI: 90 min, 0.074 °C/min; CAI: 110 min, 0.066 °C/min). In Experiment 2, sperm motility, kinetic parameters and acrosome damage for both types of doses were evaluated at 0, 24, 48 and 72 h of refrigeration. Also, morphology, pH, and osmolality were assessed at 0 and 72 h. Values for all these did not differ between CAI- and PCAI-doses. In conclusion, PCAI-doses took less time than CAI-doses to reach the desired temperature, but sperm quality was similar for CAI- and PCAI-doses during storage. Nevertheless, the different cooling curves should be taken into consideration for further investigation.

Post-cervical compared with cervical insemination in gilts: Reproductive variable assessments

The aim with this study was to compare cervical (CAI; 3 × 109 spermatozoa/90 mL) and post-cervical (PCAI; 1.5 × 109 spermatozoa/45 mL) artificial insemination (AI) techniques for frequency of incidences (unsuccessful or difficult probe passage, backflow, metritis and bleeding), values for reproductive variables and duration of the procedure in gilts. There were 644 gilts (255–270 days old, weighing 150 ± 5 kg) randomly assigned to PCAI (n = 320) and CAI (n = 324) groups. In total, there were 957 and 958 artificial inseminations performed in the CAI and PCAI groups, respectively (2–4 AIs/gilt). The frequency of unsuccessful or difficult PCAI probe passage/AI was 14.6% (140/958), therefore, there was a 85.7% probe passage success/AI rate (818/958). The semen backflow frequency/AI was less with PCAI than CAI (4.3% compared with 8.2%, P < 0.001). With the PCAI group, there were only a few cases of bleeding (11/958: 1.1% /AI) with no difference between the CAI and PCAI groups (P = 0.224). In gilts (n = 72) where there was not passage of the PCAI probe (72/320; 22.5%) there was use of CAI, (M, mixed group). For the CAI, PCAI and M groups, there were similar values for positive pregnancy diagnosis, farrowing rates and prolificacy (P > 0.05). The average duration for AI was shorter in the PCAI (2.34 ± 0.809 min) than CAI (4.77 ± 1.059 min) group, and it was longer in the M group (7.48 ± 2.454 min; P < 0.050). The PCAI procedure, therefore, is recommended for AI of gilts.

354 The effect of OvuGel® administered to weaned sows at proestrus or estrus on reproductive performance

Abstract The use of single-fixed time insemination enhances leverage of genetically superior boars. It is prudent to elucidate the appropriate strategy for using OvuGel® by season and parity given the potential economic return. It was hypothesized that OvuGel® could be used to mitigate seasonal anestrus, in particular for parity 1 sows. The objective was to evaluate reproductive performance of weaned sows administered OvuGel® (OG; n = 1342) that expressed proestrus or estrus on d 4 post-weaning, followed by a single post-cervical artificial insemination (PCAI) 24 h later. This protocol was evaluated as an alternative to treating all weaned sows regardless of estrous behavior. The Control (CO; n = 1530) sows were inseminated via PCAI after they were identified in estrus and again 24 h later if still expressing estrus. Sows were inseminated from May through November 2017. Prior to weaning, within each replicate, sows were equally assigned to OG or CO treatment by parity, genetic line, litter size, nurse sow status and health treatment status. Farrowing rate for OG was not different than CO (86.2 ± 1.2 vs. 86.6 ± 1.2%; P &gt; 0.10, respectively). There was no effect on total born between OG and CO (13.2 ± 0.1 vs. 13.3 ± 0.1; P &gt; 0.10, respectively). However, there was a parity × treatment interaction. Parity 1 OG (86.6 ± 3.0%) sows had greater farrowing rates than CO (74.5 ± 3.0%) sows (P &lt; 0.01), whereas there were no differences (P &gt; 0.05) between treatments for the other parities. These data indicate that producers can administer OvuGel® to sows in proestrus or estrus on d 4 post-weaning, followed by a single insemination 24 h later, and achieve similar performance as sows inseminated multiple times upon detection of estrus.

A new device for deep cervical artificial insemination in gilts reduces the number of sperm per dose without impairing final reproductive performance

BackgroundThe aim of this study was to evaluate the reproductive performance of a new artificial insemination (AI) device specifically designed for gilts (Deep cervical AI, Dp-CAI) by means of which the sperm is deposited deeply in the cervix (8 cm more cranial than in traditional cervical insemination-CAI). New AI techniques have arisen in recent decades in the porcine industry, such as post-cervical artificial insemination (PCAI), which involves depositing the sperm in the body of the uterus [through a catheter (outer tube)-cannula (inner tube)] rather than by CAI. Although the PCAI method has been successfully applied in farm conditions to reduce sperm doses without impairing the reproductive performance, this technique has limitations in gilts mainly because of the difficulty involved in introducing the inner cannula through the cranial part of the cervix. For this reason, the Dp-CAI method described herein may be considered as an alternative to CAI and PCAI methods in gilts.ResultsGilts were divided in two experimental groups: 1) Dp-CAI: gilts (n = 1166) inseminated using 1.5 × 109 sperm/45 mL; 2) CAI (as a control group): gilts (n = 130) inseminated using 2.5 × 109 sperm/85 mL. The Dp-CAI method was successfully applied in 88.90% of the gilts, with no differences detected between gilts with 1 or 2 previous oestrus cycles, although the catheter could be introduced more deeply in 2 oestrus gilts (P < 0.05). As the length of the insemination device that could not be introduced increased (at the moment of insemination), so the success rate of the Dp-CAI device fell, as did the total number of piglets born. When the reproductive output in CAI and Dp-CAI was compared, none of the parameters analysed [pregnancy and farrowing rates (%), and number of piglets born (total and live)] showed significant differences.ConclusionsThe use of the Dp-CAI technique provides a new AI method as an alternative to CAI and PCAI for pigs. The device, especially designed for gilts, was used with a high degree of success reducing conventional sperm doses without impairing reproductive parameters.

Morphological changes in the porcine cervix: A comparison between nulliparous and multiparous sows with regard to post-cervical artificial insemination

In recent decades, new artificial insemination (AI) methods, such as post-cervical AI (PCAI), have been developed in pig. PCAI involves crossing the cervix to deposit the sperm in the uterine body. Although PCAI application in sows is frequent, its application in nulliparous (gilts) females it is still limited due to the difficulty of passing through the cranial part of the cervical lumen. We hypothesized that ageing and parity would modify the cervical canal, facilitating the introduction of AI devices through the cervix. The aim was to compare the morphology of the uterus at different levels between multiparous and nulliparous females. Morphological analysis of the uterus pointed to a longer cervix (25.9 ± 4.6 vs. 21.6 ± 3.3 cm, p < 0.001) and greater length of the part of the reproductive tract involved in PCAI (from rima vulvae to the last cervical cushion) (56.2 ± 6.0 vs. 50.3 ± 5.2 cm, p < 0.001) in multiparous sows compared with nulliparous animals. As regards the structure of the vaginal and uterine parts of the cervix (the part in contact with the vagina and uterine body, respectively), the cross-sectional area, perimeter and total thickness were greater in the uterine part of multiparous than of nulliparous animals (area: 4.07 ± 1.46 vs. 2.46 ± 0.56 cm2, p < 0.01; perimeter: 8.50 ± 1.44 cm vs. 6.28 ± 0.92 cm, p < 0.001; thickness: 10.79 ± 0.96 vs. 8.35 ± 0.62 mm, p < 0.05), but not in the vaginal part. The tissue content analysed in histological cross-sections also showed differences between female groups, a greater content of connective tissue (58.86 ± 10.78 vs. 67.60 ± 13.38%, p < 0.001) and a lower amount of muscle fibres (39.79 ± 10.24 vs. 30.66 ± 13.69%, p < 0.001) being observed in multiparous sows. Finally, silicone casts of the cervical lumen revealed differences between the two groups in the size and shape of the ridges in the lumen trajectory. Parity, which is also influenced by ageing, determines important changes in the size, structure and tissue content of the cervix wall, as well as in the morphology of the cervical canal, which may be responsible for the different levels of performance of PCAI in the female populations. Therefore, the future design of AI strategies and catheters should take into consideration the morphological variations of the cervix lumen, which will depend on age and parity of the females.

Insertion of an intrauterine catheter for post-cervical artificial insemination in gilts: a case report

The aim of this case report was to characterize the insertion of an intrauterine catheter (IC) in gilts to perform post-cervical artificial insemination (PCAI). Attempts to insert ICs through the cervixes of gilts were performed using either a standard sow foam tip catheter (SFC; n = 25) or a standard gilt foam tip catheter (GFC; n = 25). The percentage of passage, depth and degree of difficulty for insertion were evaluated. The average depth of IC insertion was 10.1 ± 1.3 cm for SFC and 10.0 ± 1.2 cm for GFC. For both catheters, insertion depths of greater than 10 cm were achieved in the first insemination in 44% of gilts. Insertion depths of greater than 6 cm were observed in 72% and 60% of attempts using SFC and GFC, respectively. A high level of difficulty for IC insertion was observed, mainly while using GFC. In conclusion, the routine application of PCAI in gilts on swine farms remains limited by the low success rate for intrauterine catheter insertion. In further studies, we suggest evaluating reproductive performance using low insertion depths for PCAI in gilts, and assessing the use of sow foam tip catheter as a guide to introduce the IC.

Effect of incidents associated to post-cervical artificial insemination on reproductive performance of sows

Effect of incidents associated to post-cervical artificial insemination on reproductive performance of sows

Ovulation and fertility responses for sows receiving once daily boar exposure after weaning and OvuGel® followed by a single fixed time post cervical artificial insemination

Boar exposure is used to stimulate follicle development and estrus in sows after weaning and also to improve semen uptake and sperm transport with insemination. However, the need and value of boar exposure is uncertain when ovulation induction is used. These studies were designed to determine the effect of daily boar exposure after weaning when used with ovulation induction and fixed time post-cervical artificial insemination (PCAI). In experiment 1, sows were weaned into stalls and assigned to receive 3 min of daily fenceline boar exposure (BE, n = 7) or no boar exposure (NBE, n = 8). All sows received OvuGel at 96 h after weaning and BE or NBE 30 min prior to a single PCAI 24 h after OvuGel. Ovaries were assessed daily for follicle size from weaning until ovulation. Cervical contractions were measured 30 min following BE or NBE and before PCAI, while uterine contractions were measured for 1 h following PCAI. In experiment 2, weaned sows (n = 244) were assigned by parity to receive once daily BE for 1.5 min each day or NBE. OvuGel, PCAI and ultrasound methods were performed similarly as in experiment 1. Results from experiment 1 indicated BE did not significantly influence follicle size or measures of fertility. However, BE did increase the frequency of cervical contractions (P < 0.05), but with no effect on the uterus. Results from experiment 2 indicated BE had no effect on catheter passage for PCAI but did increase the proportion of sows ovulating within 48 h after OvuGel (77.7 vs 67.5%, P = 0.05), and tended (P = 0.10) to increase the proportion of sows inseminated 24 h before ovulation (70.3 vs. 61.0%). However, BE had no effect on adjusted farrowing rate (84.4 vs. 77.4%) or total pigs born (13.2 vs. 12.5) for BE and NBE, respectively. There were treatment and parity interactions for follicle size at time of OvuGel and at time of PCAI (P < 0.05) with BE minimizing parity effects on follicle size. Parity effects were also evident on farrowing rate and litter size when inseminations occurred >24 h from ovulation but not when inseminations occurred ≤24 h before ovulation. The results indicate that boar exposure for only minutes each day after weaning had beneficial effects for improving follicle development, ovulation induction, and AI timing, most notably in parity 1 sows, but had no beneficial or detrimental effects on the ability to perform PCAI.

Comparison of post-cervical and cervical porcine artificial insemination in nulliparous and multiparous

Fil: Luchetti, Carolina Griselda. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Parque Centenario; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Instituto de Investigacion y Tecnologia en Reproduccion Animal; Argentina

Optimization of post-cervical artificial insemination in gilts: Effect of cervical relaxation procedures and catheter type

Post-cervical (pC) artificial insemination (AI) has been successfully developed for application in multiparous sows, although it has proved problematic in gilts. This study analyzes the use of pC-AI in gilts by two experiments. In the first experiment, the efficiency of pC-AI in gilts was evaluated using a multi-ring multiparous catheter (MpC), which led to 23.1% of the gilts being successfully inseminated. In gilts where insemination was not possible using an MpC, two alternatives were applied before a second attempt at insemination: 1) Vetrabutin Chlorhydrate (VC) was intramuscularly injected in order to relax the cervix; or 2) Warm extender (WE) was deposited in the cervix to modify the cervical muscle dynamics. After the application of these treatments, the success rates achieved with the MpC were 34.2% and 23.8% for VC and WE, respectively. No statistically significant differences were found in the reproductive parameters measured [farrowing (%), litter size and fecundity index] between the use of MpC, or the MpC combined with VC or WE, compared with gilts inseminated by cervical AI (control group). In the second experiment, new catheters based on the anatomical characteristics of gilts (GpC) were used, and the rate of successful pC-AI application were compared (experiment 2a): a) MpC: control; b) GpC1: multi-ring catheter of Ø 16 mm and inner cannula of Ø 3.5 mm; c) GpC2: a multi-ring catheter of Ø with an inner cannula of Ø 2.5 mm. The highest rate of successful cannula penetration was reached in the GpC2 group (60.3%) followed by GpC1 (37.0%) and MpC (19.6%) (p < 0.05). There were no differences in the above mentioned reproductive parameters using the three catheters compared with cervical AI method (control group). Moreover, prior cervical AI did not improve subsequent pC-AI application 24 h later (experiment 2b). In conclusion, Vetrabutin Chlorhydrate, warm extender or the new catheters can be considered as useful tools for improving the success rate of pC-AI technique in gilts.

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

Fixed-time post-cervical artificial insemination (FTAI) drastically reduces labour requirements and increases the use of boars with higher genetic merit. This study evaluated the efficiency of eCG administration combined with/without the GnRH agonist buserelin for the induction and synchronization of ovulation in weaned sows submitted to FTAI. The sows were allocated into three groups. In the control group, the first artificial insemination was performed at the onset of oestrus and repeated every 24hr. In the eCG+GnRH group, sows received 600IU eCG at weaning and buserelin (10μg) after 86-89hr of eCG, and in the GnRH group, sows received only buserelin after 86-89hr of weaning. The hormone-treated sows received a single FTAI after 30-33hr of buserelin application. All the sows were inseminated with homospermic doses (1.5×109 sperm cells/50ml). The interval between weaning and ovulation was shorter (p<.05) in the eCG+GnRH (133.3hr) and GnRH (135.9hr) groups than the control (141.5hr) group. In the eCG+GnRH group, the sows ovulated earlier (p<.05) than those in the GnRH group (44.5 vs. 48.2hr after buserelin administration). The reproductive performance of GnRH sows was not compromised when only sows exhibiting oestrus at the time of insemination were considered, but lower farrowing rate and smaller litter size were observed in eCG+GnRH sows. The reproductive performance of eCG+GnRH sows was primarily compromised because the insemination was performed outside the optimal time relative to ovulation; therefore, it is advisable to inseminate them before 116-122hr after weaning.

New Artificial Insemination Technologies for Swine.

Better efficiency in swine artificial insemination (AI) is accomplished by reducing the necessary number of sperm cells and achieving high reproductive performance. Some strategies have been developed for use under field conditions, such as the site of sperm deposition (post-cervical AI), a single AI with control of oestrus and ovulation (fixed-time AI), and the better use of high genetic merit boars, to spread their genes as much as possible. To apply these technologies, it is important to understand some anatomical limits, physiological aspects and farm requirements. In this review, we point out some strategies to achieve higher efficiency on the use of sperm for AI technology application in swine species.

Fixed-time post-cervical artificial insemination in sows receiving porcine luteinising hormone at oestrus onset

Fixed-time post-cervical artificial insemination (FTPCAI) allows a wider use of high indexing boars and a considerable reduction in labour requirements in swine production. The aim of this study was to evaluate fixed-time artificial insemination (FTAI) efficiency using different artificial insemination protocols and porcine luteinising hormone (pLH) to induce ovulation. A total of 597 weaned sows in which oestrus detection was performed once daily (08:00 am) was allocated to three groups: FTPCAI1 (n=199) – sows received a 5-mg (4ml) intramuscular injection of pLH at oestrus onset, and were inseminated 24h later; FTPCAI2 (n=199) – sows received 5mg of pLH and were inseminated at oestrus onset (0h) and 24h after; and MultPCAI (n=199) – sows did not receive pLH, and the first AI was performed at oestrus onset (0h) and repeated every 24h during oestrus. Homospermic doses (1.5×109 total sperm cells/50ml) were used in post-cervical artificial insemination (PCAI) in all the treatments. Hormonal treatment did not affect (P>0.05) the interval between oestrus onset and ovulation (overall 32.4h) and there were no differences (P>0.05) in farrowing rate (overall 91.6%) or litter size (overall 12.6 piglets born) among treatments. In sows treated with pLH at oestrus onset, a single PCAI with 1.5 billion sperm cells did not compromise reproductive performance compared with a double PCAI at 24h intervals.