Open Veterinary Journal, (2026), Vol. 16(4): 2440-2448

Research Article

10.5455/OVJ.2026.v16.i4.45

Effect of intravaginal probiotics and enrofloxacin on vaginal microbiota, pH, vaginitis, and fertility in black Iraqi goats synchronized with progesterone impregnated sponges

Mohammedali J. Ghafil¹, Mustafa A. K. Al-Taie² and Ansam K. Mohammed^3*

¹Department of Anatomy and Histology, College of Veterinary Medicine, University of Wasit, Kut, Iraq

²Department of Biology, College of Science, University of Baghdad, Baghdad, Iraq

³Department of Microbiology, College of Veterinary Medicine, University of Baghdad, Baghdad, Iraq

*Corresponding Author: Ansam K. Mohammed. Department of Microbiology, College of Veterinary Medicine, University of Baghdad, Baghdad, Iraq. Email: ansam [at] covm.uobaghdad.edu.iq

Submitted: 12/11/2025 Revised: 26/02/2026 Accepted: 09/03/2026 Published: 30/04/2026

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ABSTRACT

Background: The prolonged retention of progesterone-infused intravaginal sponges in estrous synchronization protocols, results in alteration of vaginal microflora, disturbance of vaginal pH, and increased vaginitis in goats. These changes lead to the growth of opportunistic pathogenic bacteria, such as Escherichia coli and Staphylococcus aureus, which need antibiotics to treat this condition. Probiotics have recently been suggested as an alternative method for the maintenance of vaginal health and improving animal fertility.

Aim: To investigate the effects of probiotics (Lactobacillus plantarum and L. acidophilus), in compared with enrofloxacin and a control group, on vaginal microflora, vaginal pH, vaginitis incidence, and fertility in Black Iraqi goats synchronized with the progesterone intravaginal sponges.

Methods: Thirty adult black Iraqi goats, aged (2–4) years, were randomly divided into three separate groups, each group (n=10). The first group received a progesterone sponge only (control). The second group received progesterone sponges combined with 50 mg of intravaginal enrofloxacin. The third group received progesterone sponges combined with probiotic suspension (2 × 10⁹ CFU/sponge L. plantarum and L. acidophilus). Vaginal swabs were collected prior to sponge insertion (Day 0) and immediately after sponge removal (Day 14), for bacterial isolation, pH measurement, and cytological evaluation of vaginitis. Pregnancy was diagnosed by ultrasound 28 ± 3 after mating. Statistical analysis was performed using analysis of variance and chi-square tests.

Results: The incidence of vaginitis was significantly increased (p < 0.05) in all groups, observed 80%, 60%, and 50% in the control, enrofloxacin, and probiotic groups, respectively. The mean vaginal pH increased significantly in all groups (p < 0.001), and was highest in the control group (8.1 ± 0.16) and lowest in the probiotic group (6.9 ± 0.12) (F₂, 27=9.73; p < 0.05) after sponge removal. Escherichia coli was most predominant in all groups; it increased 90% in the control group and declined to 30% (p < 0.05) and 40% (p < 0.05) in the enrofloxacin and probiotic groups, respectively. Lactobacillus spp. increased to 70% in the probiotic group, though not significantly (p > 0.05). The pregnancy rates were 50% in the control group and 80% in both treated groups, with a highly significant difference among groups (χ²=57.6; p < 0.01).

Conclusion: The application of the intravaginal probiotic modified vaginal microflora, maintained vaginal pH, decreased vaginitis, and improved animal fertility. The probiotic efficacy was comparable to enrofloxacin without destroying beneficial bacteria.

Keywords: Enrofloxacin, Fertility, Goats, Lactobacillus spp, Progesterone intravaginal sponges.

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Introduction

Goats and sheep are considered to be seasonal polyestrous animals; the enhancing fertility in these species can be achieved by estrous synchronization protocols such as progesterone impregnated sponges, medroxyprogesterone acetate and and progesterone-releasing intravaginal device (Souza et al., 2011; Zohara et al., 2014). The physiology of reproduction can be influenced by hormonal synchronization through endocrine modulation (Alwan, 2014). One of the most prevalent protocols of oestrus synchronization in small ruminants involved the use of an intravaginal sponge that contained synthetic progestogens such as flugestone acetate (Abecia et al., 2012).

Despite their effect in regulating the estrous cycle, these methods are associated with vaginal issues such as irritation, abnormal vaginal discharge, and vaginitis (Vasconcelos et al., 2016; Al-Zubaidi et al., 2017). Recently, many studies indicated that the retention of the intravaginal sponges for long periods may lead to alterations in the vaginal microflora due to the effects of progesterone itself that lead to local immunity suppression and promote the growth of opportunistic bacteria such as Staphylococcus spp. and E. coli, resulting in vaginal dysbiosis, which may increase the risk of ascending infections to the reproductive tract that subsequently need antibiotic treatment (Altınçekiç et al., 2021; Hashim et al., 2024). In small ruminants, the use of prostaglandin F₂α is reported to enhance uterine involution and restore the normal vaginal epithelium during the postpartum period, which helps in eliminating bacterial contamination (Zaid, 2006).

Previous study in bulls reported that the combination of penicillin and ciprofloxacin can inhibit the bacterial contamination; however, these antibiotics have adverse effects on sperm characteristics, resulting in reduced semen quality (Mohammed Ali et al., 2002). Some antibiotics, like penicillin and tetracycline, are shown to be ineffective when used locally due to microbial resistance (Martins et al., 2009; Viñoles et al., 2011). In order to control vaginal microorganisms in small ruminants, many studies have used antibiotic such as enrofloxacin, which is effective in controlling pathogenic bacteria; however, its use is associated with significant issues such as residues of antibiotics in milk and potentially affecting natural balance of microflora in the vagina (Ojeda-Hernández et al., 2019; Güner et al., 2022; Toquet et al., 2025). Therefore, there is interest in investigating alternative methods for administering antibiotics, such as intravaginal probiotics (Güner et al., 2022; Güner et al., 2024; Güner and Güner, 2025).

Probiotic bacteria, especially L. plantarum, Lactobacillus gasseri, and Lactobacillus brevis, are recognized for their contribution to the maintenance of health in the vagina. They provide protection effects by synthesizing antimicrobial compounds such as bacteriocins, competitively excluding pathogens, and regulating vaginal pH. Also, the administration of probiotic inoculation in sheep flocks has been associated with increased fertility and pregnancy rates, indicating a protective role and microflora-stabilizing function (Quereda et al., 2020; Güner and Güner, 2025).

Despite these positive findings in ovine, no published studies have investigated the effect of probiotic-loaded intravaginal sponges on caprine vaginal microflora. As a result of the differences between caprine and ovine in immune responses and vaginal microflora, it should be investigated if caprine have the same benefits from vaginal probiotics. This study aimed to evaluate the effects of intravaginal probiotics and enrofloxacin on vaginal microflora, pH, vaginitis, and fertility in goats treated with progesterone sponges.

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Materials and Methods

The investigation was conducted in Al-Asema private farm, Baghdad, Iraq, during the breeding season. A total of thirty adult black Iraqi goats, aged (2–4) years, were randomly divided into three separate groups, each group (n=10), and underwent vaginal inspection prior to sponge insertion. The experimental group size was determined by logistical and resource considerations associated with conducting a field trial. For estrous synchronization, commercial intravaginal sponges infused with 40 mg of flugestone acetate (Chronogest CR®, Intervet, Netherlands) were inserted into the vagina in each group that received them for 14 days.

The first group received sponges with flugestone acetate only (control group). The second group received flugestone acetate sponges combined with 50 mg of intravaginal enrofloxacin. The third group received flugestone acetate sponges combined with a commercial probiotic containing L. plantarum and L. acidophilus.

For probiotic preparation, a commercially lyophilized probiotic product, "Vitalactic B" (Vitane Pharma GmbH, Germany), contains two probiotic strains: Lactobacillus plantarum and L. acidophilus, with a concentration of 2 × 10⁹ CFU per capsule. The capsule was carefully opened, and its contents were transferred into a sterile 1.5 ml Eppendorf tube and suspended in 1 ml of lactic acid bacteria medium Man–Rogosa–Sharpe (MRS broth, formulated by Oxoid™, UK). Lyophilized Lactobacillus spp. remain in a dormant state after freeze-drying and are designed to survive storage without prior cultivation; upon rehydration in an appropriate nutrient medium, metabolic activity can be restored (Arellano-Ayala et al., 2021).

After suspension, the entire 1 ml of the probiotic bacteria suspension was aspirated with a sterile 1 ml insulin syringe (26 G) and injected onto the posterior surface of the sponge relative to applicator position (i.e., the surface facing vaginal mucosa upon insertion), after it was loaded into the vaginal applicator, followed by immediate intravaginal insertion. This allowed Lactobacillus spp. to be interfaced with the vaginal mucosa at the time of insertion and aimed to achieve uniform dosing among animals.

The reason for the selection dose (2 × 10⁹ CFU/sponge) was based on previous studies on ovine. Quereda et al. (2020) and Toquet et al. (2025) used lower doses (10⁴, 10⁶, and 10⁸ CFU), which resulted in improvements in vaginal inflammation and fertility without significant suppression of pathogenic bacteria after sponge removal. Therefore, a higher dose was selected to enhance the likelihood of observing a measurable effect on vaginal microflora.

From each group, vaginal swabs were collected prior to sponge insertion (Day 0) and immediately after sponge removal (Day 14). The swabs were placed in sterile Amies transport medium (Oxoid™, UK). Samples were maintained in refrigeration until processing occurred within a period not exceeding 12 hours.

For bacterial isolation and identification, swabs were inoculated onto blood agar (Oxoid™, UK) enriched with 5% defibrinated sheep blood, MacConkey agar (Oxoid™, UK), and de MRS agar (Oxoid™, UK). The plates were incubated at 37ºC for 24–48 hours under aerobic or microaerophilic conditions as appropriate. The different isolates were initially evaluated macroscopically for colony colour, consistency, and haemolysis on blood agar. Microscopically evaluation by using Gram staining (HiMedia, India) to determine Gram reaction and cellular morphology. Catalase, oxidase, and common biochemical tests were used for initial identification.

The confirmed identification of E. coli, Staphylococcus spp., and Streptococcus spp. was achieved by biochemical methods in the Vitek₂ system (bioMérieux, France), according to the manufacturer's instructions (Pincus, 2006; Fritsche et al., 2011). It used specific cards for Gram-negative (ID-GN) and Gram-positive (ID-GP) bacteria. Lactobacillus spp. was not subjected to Vitek₂ due to database limitations.

The vaginal pH was measured before sponge insertion (Day 0) and after sponge removal (Day 14) in all groups. A vaginal swab was rubbed on pH indicator strips (HiMedia, India; range 0–14: precision ± 0.5). This method was selected due to its practicality and suitability for use under field-based conditions involving multiple animals.

To evaluate the vaginitis, vaginal swabs were taken before and after sponge insertion, then rolled onto a clean glass slide, air-dried, and fixed with methanol for hematoxylin and eosin staining. Slides were examined under a light microscope at 400 × magnification. The mean count of inflammatory cells (neutrophils and macrophages) from 10 microscopic fields was recorded. This method was previously described by Quereda et al. (2020) and Toquet et al. (2025). A score of 0 (no vaginitis) was assigned for ≤3.9 neutrophils/field, and a score of 1 (vaginitis) for values >3.9 according to Quereda et al. (2020) and Toquet et al. (2025).

For fertility evaluation, 1 day after the sponge removal, fertile bucks with crayon marks were introduced for natural mating at a ratio of 1:5 (buck: does). The estrus detection was performed at 12-hour’ intervals for 5 days; oestrus was detected by observation of crayon mark points on the rumps of the does (Yong and Lee, 2014). A portable veterinary ultrasound machine (DP-10Vet, Mindray Animal Care, China) was used to determine the pregnancy rate 28 ± 3 days after mating (Suguna et al., 2008). Statistical analysis was performed using ANOVA and chi-square tests. This was performed using SAS (2010).

Ethical approval

Ethical approval was granted by the ethical review committee of Department of Microbiology, College of Veterinary Medicine, University of Baghdad, Iraq, under license number P.G./2733 in 2 /11 /2025.

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Results

The vaginitis was evaluated based on vaginal cytology and is presented in Table 1. The animal was classified as having vaginitis when the mean count of neutrophils was more than 3.9 cells per field, as previously described in the methodology. In the control group, 40% of animals were diagnosed with vaginitis before sponge insertion, which increased to 80% after sponge removal (χ²=13.3, p=0.01). In the enrofloxacin-treated group, prior to sponge insertion, 30% showed vaginitis, and after sponge removal, 60% of animals were diagnosed with vaginitis (χ²=10, p=0.01), whereas in the probiotic group, at day 0%, 30% of animals were diagnosed with vaginitis; following sponge removal, 50% of animals were diagnosed with vaginitis (χ²=5, p=0.05). Overall, the incidence of vaginitis was significantly increased (p < 0.05) in all groups, observed from 40% to 80%, 30% to 60%, and from 30% to 50% in the control, enrofloxacin, and probiotic groups, respectively.

Table 1. Vaginitis percentage (%) before vaginal sponge insertion and after sponge removal in Black Iraqi goats.

In all groups, the vaginal pH was obtained before insertion and after sponge removal (Table 2). Vaginal pH increased significantly in all groups post-treatment (p < 0.001). In the control group, pH rose from 6.6 ± 0.19 to 8.1 ± 0.16. In the enrofloxacin group, it increased from 6.8 ± 0.12 to 7.4 ± 0.09, and in the probiotic group, from 6.5 ± 0.11 to 6.9 ± 0.12. Post-treatment comparisons showed significant differences (F₂, 27=9.73; p < 0.05), with the highest pH in the control group and lowest in the probiotic group.

Table 2. Vaginal pH before sponge insertion and after sponge removal in Black Iraqi goats.

The results of microbiological culture (Table 3) indicate that the E. coli isolation was predominant in all groups. Presumptive E. coli isolation produced smooth, non-hemolytic colonies on blood agar and pink lactose-fermenting colonies on MacConkey agar. Microscopically, the isolations were identified as Gram-negative rods and catalase-positive. Staphylococcus aureus produced typical β-hemolytic colonies on blood agar, identified as Gram-positive cocci in clusters, and was catalase-positive. Streptococcus isolation exhibited small colonies on blood agar, which were observed as Gram-positive cocci arranged in chains, and catalase negative. Lactobacillus spp. were isolated on MRS agar, microscopically appeared as Gram-positive rod-shaped, and were catalase negative.

Table 3. Bacterial isolation percentages (%) before vaginal sponge insertion and after vaginal sponge removal in Black Iraqi goats.

In the control group, before sponge insertion, E. coli were observed in 6/10 animals (60%), followed by S. aureus in 2/10 animals (20%), Streptococcus spp. in 2/10 animals (20%), and Lactobacillus spp. in 3 animals (30%). After sponge removal, E. coli persisted in 9 out of 10 animals (90%), S. aureus was detected in 4 animals (40%), Staphylococcus spp. in 3 animals (30%), and Lactobacillus spp. in 4 animals (40%). One animal did not show bacterial growth at any time. Observed after sponge removal, there were statistically significant increases in E. coli and S. aureus (p < 0.05 and p < 0.01, respectively).

In the probiotic group, E. coli decreased from 60% to 40% (χ²=4; p < 0.05), S. aureus dropped from 40% to 20% (χ²=6.6; p < 0.01), and Streptococcus spp. appeared in only 10% (χ²=7.3; p < 0.01). Lactobacillus spp. Increased from 40% to 70%, though the change was not statistically significant (χ²=3.33; NS).

In the enrofloxacin group, before sponge insertion, E. coli was isolated in 5/10 animals (50%), S. aureus isolates in 4/10 animals (40%), Streptococcus spp. was only isolated from 1/10 animals (10%), and Lactobacillus spp. isolates in 3/10 animals (30%). After sponge removal, E. coli isolates in 3/10 animals (30%), S. aureus isolates in 2/10 animals (20%), Streptococcus spp. isolates in 1/10 animals (10%), and Lactobacillus spp. isolates in 2/10 animals (20%). The E. coli and S. aureus reduce significantly (p < 0.05 and p < 0.01, respectively).

All animals exhibited estrus after sponge removal. The pregnancy rates (Table 4) were 80% in both the probiotic and enrofloxacin groups, compared to 50% in the control. This difference was statistically significant (χ²=57.6; p < 0.01), suggesting both treatments improved fertility.

Table 4. Pregnancy rate percentages (%) after vaginal sponge removal in Black Iraqi goats.

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Discussion

This is the first study that investigated the effect of intravaginal Lactobacillus plantarum in goats. However, in ewes, two studies evaluate the effect of L. plantarum or its cell-free supernatant on vaginal health, Guner et al. (2022) reported that despite the use of L. plantarum cell-free supernatant not resulting in significant differences in the reduction of total vaginal bacterial count, it was effective in decreasing the number of Enterobacteriaceae counts, which are the most important opportunistic bacteria causing vaginal inflammation in ewes. Guner et al. (2024) used a concentration of 1 × 10⁸ CFU of L. plantarum per sponge, demonstrating the safety of L. plantarum and its supernatant, although it did not have a significant reduction in vaginal discharge or odour.

Quereda et al. (2020) investigated a lyophilized commercial probiotic that contains specific strains of Lactobacillus spp. (L. crispatus, L. brevis, and L. gasseri) in ewes. The study used two different concentrations (1 × 10⁶ CFU/ml and 1 × 10⁴ CFU/ml) that were administered intravaginally, and reported a decrease in neutrophilic inflammation from 80% in the control group to 36% in the treated group, which indicates the vaginal immune response. In ewes, Güner et al. (2022) reported that intravaginal enrofloxacin was more effective than Lactobacillus plantarum cell-free supernatant in reducing vaginitis severity, while L. plantarum treatments mainly reduced Enterobacteriaceae counts without markedly improving clinical vaginitis during intravaginal progesterone synchronization protocols.

Similarly, Toquet et al. (2025) investigated novel intravaginal probiotic inoculation using commercial probiotic Lactobacillus spp. (L. crispatus, L. brevis, and L. gasseri) in ewes. In their trial, a dose of 3.24 × 10⁸ CFU/ml was used intravaginally, and its effect on microbiota was characterized by using molecular analysis based on 16S rRNA gene sequencing, in addition to evaluation of vaginitis and fertility outcomes. The results demonstrated that the use of probiotics positively modulates the microbiota, and vaginal inflammation, derived from the use of intravaginal sponges, is also associated with improved conception rate.

These findings in ewes suggest the potential of Lactobacillus spp. as a safe alternative to antibiotics in vaginal health. This study used a 10–20-fold higher concentration (2 × 10⁹ CFU/sponge) of commercial probiotic strains (Lactobacillus plantarum and Lactobacillus acidophilus) compared to those used in previous studies. The high dose administered to goats explained the reduction of E. coli, and the marked increase in Lactobacillus spp. isolates suggested that pathogenic bacteria were reduced and normal vaginal flora was restored, compared to the lower doses used in ewe-based studies. It is thought to be related to the high dose of Lactobacillus spp., which may enhance Lactobacillus competitiveness and the secretion of bacteriocins.

Prolonged use of progesterone-impregnated sponges alters the vaginal environment, elevates pH, increases pathogen-colonization, and raises vaginitis incidence. This supports prior findings that long-term progesterone suppresses local immunity and promotes opportunistic bacterial growth.

In the control group, the percentage of E. coli isolation increased from 60% to 90% after sponge removal (χ²=6; p < 0.01), similarly, the S. aureus increased from 20% to 40% (χ²=6.6; p < 0.01). These findings agree with previous studies that reported increasing E. coli following estrous synchronization with sponge-loaded progesterone, the sponge inducing intravaginal irritation and accumulation of secretions, improving growth of these pathological bacteria (Güner et al., 2024). In enrofloxacin treated group, the percentage of E. coli isolation decline from 50% to 30% (χ²=5; p < 0.05) and S. aureus from 40% to 20% (χ²=6.6; p < 0.01), suggesting reduction in the growth of opportunistic pathogenic bacteria, these results agree with Hashim et al. (2024), who reported that E. coli isolation sensitive to enrofloxacin. However, the enrofloxacin treatment related with reducing of Lactobacillus spp. From 30% to 20% (χ²=2; NS), yet it may be a trend indicating that these antibiotics could disrupt the beneficial bacteria. In the probiotic-treated group, there is a significant reduction in the E. coli isolation from 60% to 40% (χ²=4; p < 0.05) and a highly significant decrease in S. aureus from 40% to 20% (χ²=6.6; p < 0.01), simultaneously increasing in the Lactobacillus spp. from 40% to 70%, in spite of these increasing was not statistically significant (χ²=3.33; NS). This upward trend of Lactobacillus spp. suggests a competitive inhibition of the growth of opportunistic pathogenic bacteria and restores vaginal microflora balance, throughout the production of bacteriocins and lactic acid, as previously demonstrated in vitro by Mohammed et al. (2022). Our findings agree with Güner and Güner (2025), who demonstrated the role of Lactobacillus plantarum in improving vaginal health and reproductive performance during progesterone-based synchronization in ewes.

The isolation of opportunistic bacteria across all groups supports the hypothesis reported by Al-Zubaidi et al. (2017) that intravaginal sponges act as foreign bodies that lead to inflammation and proliferation of microorganisms. On the other hand, the probiotic-treated group exhibited the lowest increases in these bacterial populations after sponge removal, suggesting modifications effect of Lactobacillus spp. on vaginal microflora balance.

The alterations of vaginal flora were accompanied by significant alterations in vaginal pH between different groups, which reveled to relation between increasing pH and vaginal flora. In all groups, the pH of the vagina elevated significantly after sponge removal (p < 0.001), which reveals that the progesterone-impregnated sponges changed the vaginal environment. Despite the limitations of the pH indicator strips, the shifting in the probiotic group toward near-physiological pH is biologically important when considered with microbial and inflammatory parameters in vaginal health.

In the control group, there was elevation in pH significantly from (6.6 ± 0.19) before insertion to (8.1 ± 0.16) after sponge removal (p=0.01), which means the intravaginal sponges may alter the vaginal environment. These results agree with the findings of a previous study in ovine, which demonstrates that the elevation in pH after removal of the intravaginal device is due to alteration in vaginal microflora (Martinez-Ros et al., 2018).

Sitaresmi et al. (2019) reports the vaginal pH in goats under normal conditions ranges from 6.1 to 6.8 through the proestrus, metestrus, and diestrus phases of the estrus cycle. These outcomes indicate, the vaginal pH near 6.5 serve as a state of healthy condition in the non-estrus phase of goats. The vaginal pH of nearly 6.5 provided an unfavorable environment for the growth of many pathogenic bacteria, which led to the improvement of vaginal health and the correction of dysbiosis (Gómez-Martín et al., 2015).

In the probiotic group, there was a slight elevation in the vaginal pH from (6.5 ± 0.11) to (6.9 ± 0.12) (p=0.01) after removal of sponges; this elevation reveals that the probiotics contribute to maintaining the normal health conditions of the vaginal environment. This outcome contrasts with those of Toquet et al. (2025), who reported a significant elevation in the vaginal pH in ewes treated with intravaginal probiotics after sponge removal. On the other hand, the variation suggested related different factors, such as the species of the animals or dose of probiotic. In the enrofloxacin group, there was a moderate increase in vaginal pH from (6.8 ± 0.12) to (7.4 ± 0.09) (p=0.01); these results though, may be related to the antimicrobial effect of enrofloxacin, that killing both pathogenic and beneficial bacteria.

The changes in vaginal bacteria and pH were related to different degrees of vaginitis. The results in (Table 1) Show varying degrees of vaginitis before insertion and after sponge removal. Before sponge insertion, the vaginitis was about 30%–40% in all groups. This inflammation is thought to be related to many environmental and microbial factors. After sponge removal, there are significant increases in inflammation (χ²=7.3, p < 0.05) with different degrees across the treated groups. In the control group, the vaginitis increased from (40%) before sponge insertion to (80%) after sponge removal (χ²=13.3, p=0.01). This increase indicated that the retention of the sponge for 14 days without antimicrobials may enhance the growth of opportunistic bacteria, as confirmed in bacterial isolation. Manes et al. (2018) reported a relationship between the intravaginal sponges and vaginal health problems such as vaginal inflammation and bacterial colonization.

In the enrofloxacin group, there was an elevation in the incidence of vaginitis that increased from 30% to 60% (χ²=10, p=0.01), indicating a moderate positive effect. On the other hand, the antibiotics are bactericidal against pathogenic bacteria and may have the same effect on beneficial bacteria, especially Lactobacillus spp., as suggested by Guner et al. (2024). These inflammations could be related to changes in the vaginal microflora balance or inadequate support for vaginal mucosal healing.

In the probiotic group, there were slightly lower increases in vaginitis incidence in all groups from (30% to 50%) (χ²=5, p=0.05). Although there was no statistical significance, it suggests a moderate effect of Lactobacillus spp. in the maintenance of vaginal health. These probiotics are known to secrete substances, such as bacteriocins, that inhibit the growth of many pathogenic bacteria and produce lactic acid that maintains pH (Mohammed et al., 2022). The moderate increase in vaginal inflammation is thought to be due to the sponge, which acts as a foreign body.

The retention of the sponge for many days leads to an immune response; lymphocytes and macrophages play a defensive role (Hussin and Zaid, 2011). The alteration in the vaginal bacterial population, pH, and vaginitis is associated with reproductive performance. The effect of these treatments on estrus expression and pregnancy rate was reported. After removal of sponges, all animals showed estrus expression, thus meaning the success of synchronization programmes in all groups. On the other hand, the pregnancy rate differs significantly between different groups (χ²=57.6, p < 0.01). The animals treated with probiotics or enrofloxacin recorded a high pregnancy rate (80%) compared with the control group (50%).

These results support the hypothesis that modulation of vaginal microbiota may improve vaginal health, in agreement with an in vitro study that demonstrated the antimicrobial activity of Lactobacillus spp. against pathogenic bacteria (Mohammed et al., 2022). Histomorphometric studies have revealed that goats exhibit a compensatory reproductive response after unilateral ovariectomy, indicating a high reproductive resilience in goats (Al-Khazraji et al., 2016). Similarly, in local Iraqi goats, the genetic variations in the melatonin receptor 1A gene influence reproductive efficiency, which means that the improvement of fertility can be achieved by hormonal and biological modulation (Ali and Ibrahim, 2019).

The limitation of this study involved the relatively low number of animals in each group (n=10 per group), which was determined by logistical considerations and field conditions. Despite the low number of samples, there are significant differences among the control and treated groups. The pH indicator strips have lower accuracy (± 0.5) compared to a digital pH meter. In addition, the bacterial identification is based on isolation without bacterial counting evaluation (CFU/ml). Molecular identification of Lactobacillus spp. and enrofloxacin residue analysis were not performed. We recommended further studies in the future to investigate the effect of Lactobacillus spp. on reproduction performed in black Iraqi goats, involving molecular approaches and quantitative bacterial evaluation.

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Conclusion

Administration of intravaginal probiotic bacteria (Lactobacillus plantarum and L. acidophilus) in progesterone-infused sponges resulted in a reduction of opportunistic pathogenic bacteria, maintained the vaginal pH and lowers vaginitis incidence compared with the control. The pregnancy rate also increased in the probiotic-treated group, showing comparable efficacy to enrofloxacin without destroying beneficial bacteria. The results of this study indicate that intravaginal probiotic bacteria are safer than antibiotics, and maintain vaginal health and improve fertility in Black Iraqi goats.

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Acknowledgment

The authors would like to thank the management and staff of Al-Asema privet farm, (Baghdad province, Iraq) for their contribution in facilitating the completion of this scientific research. Also, we extend our sincere thanks and gratitude to Prof. Dr. Talal K. Al-Zubaie, Chairman of the Legal Committee in the Iraqi Parliament, for his support of this project.

Conflict of interest

The authors assert that there are no conflicts of interest pertaining to the publishing of this paper.

Funding

This research did not obtain any specific financing from public, commercial, or non-profit entities.

Authors’ contributions

Mohammedali J. Ghafil and Mustafa A. K. Al-Taie performed the practical field work and supervised the experimental procedures at Al-Asema Farm. Ansam K. Mohammed conducted the bacterial isolation and laboratory analyses. Mohammedali J. Ghafil and Manal Hatem contributed to the data interpretation, manuscript writing, and final editing. All authors read and approved the final version of the manuscript.

Data availability

The datasets produced and/or examined in this investigation are accessible from the corresponding author upon reasonable request.

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