Abstract in English:

Abstract Considering the clinical importance and the frequent occurrence of several testicular pathologies, this study aimed to assess the prevalence of testicular disorders in dogs and cats and examine their association with species, breed, and age. In order to achieve this, ultrasound reports from the hospital’s system were utilized. The odds ratio was calculated for species and breed, while Pearson’s correlation test was used for age. A total of 1,282 dogs and 728 cats were examined. Of these, only the intact animals were considered susceptible to testicular conditions — 1,047 dogs (81.6%) and 218 cats (29.9%). Among dogs, 33.05% presented at least one testicular disorder, compared to 10.55% of cats. The most prevalent conditions were ectopia and degeneration, with neoplasia being frequently observed in canines. Other conditions identified included orchitis, fibrosis/microcalcification, cysts, hydrocele, monorchidism, torsion, and traumatic rupture. Canine species had a higher risk of testicular disorder and cryptorchidism. In dogs, age was strongly and positively related (p<0.001) to a higher prevalence of disorders. For general testicular disorders, poodle and pinscher breeds showed higher risks, while rottweilers had a lower risk compared to mixed-breed dogs. For ectopia, pinscher, shih-tzu, and poodle breeds had higher risks. Thus, it is evident that testicular , while less prevalent conditions deserve greater attention . In felines, the occurrence is less frequent and congenital conditions like ectopia and monorchidism are more common.

Abstract in English:

Abstract The reproduction of some fish species in captivity is only possible by imposing artificial reproductive procedures, and the manipulation of fish for these purposes is a stressor. Thus, anesthesia can reduce stress during handling. However, it is necessary to investigate the possible side effects on breeding and the general health of the animal. Therefore, we aimed to investigate the impact of tricaine methanesulfonate (MS-222) and eugenol (EUG) at concentrations of 300 mg L-1 and 40 mg L-1, respectively, on several stress- and reproductive-related parameters in Rhamdia quelen anesthetized before semen collection. After hormonal induction, 24 sexually mature males (534.4 ± 259 g) were randomly assigned to treatment groups and semen and blood samples were collected. Anesthesia recovery and induction time were extended in fish anesthetized with EUG; however, plasma cortisol concentrations did not differ among the treatment groups. EUG caused higher DNA fragmentation in blood cells than in the control group (without anesthesia). EUG increased the monocyte count compared to the other experimental groups. MS-222 showed a lower sulfhydryl group (SH) quantitation than the other experimental groups. The anesthetics used before semen collection in this study had no adverse effects on the fertilization or hatching capacity of anesthetized R. quelen. MS-222 (300 mg L-1) and EUG (40 mg L-1), despite being related to hematological and semen changes, did not negatively affect the reproductive capacity of R. quelen males. Thus, anesthesia is recommended for R. quelen during semen collection, considering reproductive parameters and animal welfare.

Abstract in English:

Abstract Bees are essential pollinators with species differing morphologically and physiologically. Understanding the variations in reproductive parameters between phenotypes is crucial. This study compares the sperm characteristics of Italian (Apis mellifera ligustica) and Africanized drones (Apis mellifera L.) raised in the Caatinga biome. Nine sexually mature Italian drones and sixteen Africanized drones from different colonies were used. Semen was collected using the endophallus eversion technique and diluted in saline solution (1:20). The parameters analyzed included: motility (optical microscopy), sperm viability (Hoechst 33342; propidium iodide), functional integrity of the plasma membrane (hypo-osmotic test), morphology and morphometry (Rose Bengal), and scanning electron microscopy. The results were expressed as mean ± standard error. Statistical analyses included the Shapiro-Wilk test to the normality of residuals and the Bartlett test to verify homoscedasticity. Comparisons between groups were performed using the Mann-Whitney and Student's t-tests (P < 0.05). Both phenotypes presented 90% sperm motility with viability of 82.4 ± 2.5% for Italians and 81.1 ± 2.4% for Africanized ones; the functional integrity of the plasma membrane was 93.4 ± 1.8% and 91.6 ± 1.5%, respectively. Regarding morphology, the percentage of normal sperm was 10.89 ± 1.66% for Italian and 12.06 ± 1.01% for Africanized, with the curled tail being the most predominant feature of sperm morphology. No statistically significant differences (P > 0.05) were observed for the above-mentioned parameters. Sperm head morphometry was significantly larger (P < 0.05) in Italian (10.04 ± 0.03 µm) compared to Africanized (9.33 ± 0.04 µm). Scanning electron microscopy analysis revealed no ultrastructural differences between phenotypes. In conclusion, there is a high degree of similarity in sperm parameters of both phenotypes under the same environmental conditions, indicating the feasibility of applying similar reproductive strategies.

Abstract in English:

Abstract Approximately 85% of embryos produced in Brazil are in vitro (IVP). However, the success of IVP is still quite diverse, and several factors need to be coordinated to obtain a live calf from an oocyte. This study aims to evaluate the influence of the donor breed (Nellore vs. Senepol) and the seasons of year (Dry vs. Rainy) at the time of follicular aspiration (OPU) on the number of viable oocytes and embryos produced, and the recipients pregnancy rate per embryo transfer (P/ET). Data from 368 donors was evaluated, 198 Senepol and 170 Nellore, resulting in a total of 21,758 oocytes collected by OPU. During the period a total of 4,740 embryos were produced (2,135 Senepol and 2,605 Nellore) and 2,124 fresh embryo transfers were analyzed. A negative effect of dry season was observed on number of total and viable oocytes for Nellore. The embryo production rate was lower for Senepol in both periods. Nellore breed had lower embryo production rate in the rainy period. The P/TE was lower for embryos from Senepol donors during dry season, while the P/TE of embryos from Nellore donors was not affected by season. In conclusion, the dry season negatively influences total and viable oocyte collection in Nellore donors, while in Senepol donors remained constant throughout the year. The embryo production of Nellore donors is negatively influenced by rainy season, although it remains higher than the Senepol donors throughout the year, and P/TE of the embryos of Senepol donors is reduced during the dry season.

Abstract in English:

Abstract We aimed to evaluate puberty induction, follicular dynamics, and hormonal profiles of progesterone (P4) and estradiol (E2) in prepubertal Nelore and Murrah heifers subjected to synchronization for fixed-time artificial insemination (FTAI). Six Nelore heifers (14 to 17 months old; 320 to 350 kg) and six Murrah heifers (14 to 17 months old; 422 to 523 kg) confirmed as prepubertal by ultrasonography due to the absence of a corpus luteum were used. The protocol included an intravaginal P4 device (0.5 mg) on D0, along with the administration of estradiol benzoate (EB) and prostaglandin F2α. In Nelore, the device was removed on D7, followed by the administration of estradiol cypionate, prostaglandin F2α, and eCG, with insemination occurring 48–56 hours after intravaginal device removal (D9). In Murrah, the device was removed on D9, followed by prostaglandin F2α and Ecg administration, with insemination on D12 after GnRH administration (D11). Blood samples were collected (Nelore: D7 and D9; Murrah: D9 and D12) to measure hormone levels, and ultrasonography monitored follicular dynamics and ovulation. The ovulatory follicle diameter was 7.83 ± 2.25 mm (Nelore) and 7.7 ± 1.63 mm (Murrah), with no significant differences (P > 0.05). The dominant follicle diameter at P4 device removal was 6.5 ± 1.59 mm (Nelore) and 6.9 ± 4.97 mm (Murrah). The mean P4 levels were 0.76 ng/mL (Nelore) and 1.42 ng/mL (Murrah) at P4 device removal, and 1.00 ng/mL and 0.52 ng/mL at the moment of FTAI. The mean E2 levels were 9.28 pg/mL (Nelore) and 26.75 pg/mL (Murrah) at the P4 device removal, and 11.20 pg/mL and 11.59 pg/mL at the moment of FTAI. Ovulation rates were 100% in Nelore and 50% in Murrah. These results highlight the importance of tailoring FTAI protocols to the specific reproductive characteristics of each breed.

Abstract in English:

Abstract Capybaras (Hydrochoerus hydrochaeris) are increasingly synanthropic throughout South America, where their rapid population growth in human-altered landscapes heightens conflicts and, critically, elevates the public health risk of Brazilian Spotted Fever (BSF), a lethal Rickettsia rickettsii zoonosis transmitted by Amblyomma sculptum ticks. Since capybara density is tightly coupled with pathogen circulation, non-lethal, scalable management strategies are essential. We evaluated the long-term efficacy and safety of the single-dose GonaCon™ immunocontraceptive vaccine in free-living, sexually mature female capybaras (n=6 treated, n=3 control) ~ 33 months. All treated females demonstrated sustained reproductive suppression (absence of parturition or estrus behavior; p < 0.01). Efficacy was confirmed by multi-modal evidence: plasma progesterone (P4) and estradiol (E2) concentrations were significantly suppressed, showing reductions of 41% and 36% by Day 27 post-vaccination, respectively (p < 0.005; Cohen’s d > 1.5). Histological analysis validated HPG axis disruption, revealing significantly lower ovarian weights (p=0.002) and suppressed folliculogenesis, with treated ovaries possessing drastically fewer antral follicles (mean 2.3 ± 0.5 vs. 12.7 ± 1.2 in controls; p<0.001). The treatment was safe, with the only adverse effect being a transient, localized swelling in 4/6 animals that resolved within two weeks. Importantly, treated females maintained critical social behaviors, including alloparental care. These findings provide strong evidence for the sustained, multi-year efficacy of GonaCon in a large wild rodent, supporting its use as a humane, non-surgical tool for density management and BSF risk mitigation under the One Conservation Paradigm.

Abstract in English:

Abstract This study evaluated the toxicity of cryoprotectants and the performance of low-rate freezing protocols for oocytes and embryos of Piaractus brachypomus, a Neotropical fish of increasing relevant for Brazilian aquaculture and genetic conservation. Eight cryoprotectant solutions based on methanol (MeOH) or dimethyl sulfoxide (Me2SO), combined with 0.25 M sucrose in L-15 or HBSS media, were tested for oocytes toxicity at 28 °C and post-freezing viability. In spite of histological and scanning electron microscopy (SEM) analyses indicated preservation of gross morphological features, none of the cryopreserved oocytes supported embryonic development, indicating loss of functional viability following cryoprotectant exposure and freezing. For embryos, two low-rate freezing protocols were evaluated: Protocol 1 (P1E), based on gradual cooling to −13 °C, and Protocol 2 (P2E), involving linear cooling to −60 °C followed by storage in liquid nitrogen. In P1E, eight treatments using 3.1 M MeOH combined with different concentrations of polyvinylpyrrolidone (PVP) or sucrose were tested. The highest proportion of morphologically viable embryos (15.3%) was obtained with MeOT + 0.45 M sucrose (SC5), which different significantly from the other treatments. In contrast, no morphologically viable embryos were recovered after P2E, likely due to inadequate dehydration and intracellular ice formation. Overall, high concentrations of permeant cryoprotectants and prolonged equilibration times were detrimental to oocyte and embryo viability, while sucrose showed better cryoprotective performance than PVP. Even though protocols tested were insufficient to ensure consistent post-thaw viability, the partial success observed in P1E under MeOH and sucrose combinations provides a relevant experimental basis for future refinement of conservation strategies and contributes to development of ex situ germoplasm conservation approaches for P. brachypomus and other Neotropical species.

Abstract in English:

Abstract This study investigated the effects of lauric acid (LA) supplementation during in vitro maturation (IVM) of bovine oocytes on nuclear maturation and subsequent embryonic development. Cumulus–oocyte complexes (COCs) were matured in medium containing LA at concentrations of 50, 100, 150, 200, or 300 µM, or without LA (control). Embryo development following in vitro fertilization (IVF) and culture (IVC) was assessed. Based on optimal outcomes in the first experiment (A total of 1,558 oocytes were used across 6 - 8 replicates per treatment group),200 µM LA was selected to evaluate its protective role under cellular stress. Oocytes (n = 1,255; five replicates) were matured with or without 200 µM LA and exposed to heat stress (41 °C) or oxidative stress (1 mM H2O2). LA supplementation significantly improved blastocyst rates, with 100 - 200 µM groups showing higher formation rates (≥ 37.1%) compared to control (21.3%) (p < 0.05). Blastocyst quality, based on A–B grade embryos, was also enhanced in the 200 µM (51.1%) and 300 µM (56.5%) groups versus control (19.2%) and 50 µM (16.9%) (p < 0.05). Stress exposure reduced maturation and blastocyst rates. Oxidative stress significantly decreased maturation (OS: 44.9%) and blastocyst development (18.6%) compared to control (72.3% and 28.4%, respectively), while LA treatment improved these outcomes (OS-LA: 51.5% and 31.5%) (p < 0.05). Under heat stress, LA showed a non-significant trend toward higher blastocyst rates (24.8%) compared to stress alone (16.2%). Under normal conditions, 200 µM LA significantly enhanced blastocyst yield (44.2%) versus control (28.4%) (p < 0.05). Data were analyzed using ANOVA with post-hoc tests, and differences were considered significant at p < 0.05. These results indicate that LA supplementation during IVM enhances bovine embryo developmental competence and partially mitigates oxidative stress-induced impairment.

Abstract in English:

Abstract This study aimed to evaluate the applicability of fetal heart rate variability (FHRvar%), umbilical artery resistivity index (RI-UmbArt), and maternal body temperature (Temp, °C) for predicting parturition in bitches. Fifteen bitches (1-6 years old) were included. Gestational age was estimated using fetal biometry (inner chorionic cavity or biparietal diameter), and during the last week of pregnancy the animals were evaluated twice daily until parturition. Data were retrospectively grouped according to the hours before parturition (HBP). The evaluated parameters were FHRvar% (measured over 5-10 minutes using pulsed Doppler abdominal ultrasonography), RI-UmbArt (assessed by triplex Doppler in three fetuses per session), and Temp (rectal thermometry). Data were statistically compared and correlated with HBP. FHRvar% showed a gradual increase (P = 0.010) beginning at 84 HBP, reaching a peak between 24 and 12 HBP, whereas Temp significantly decreased during the last 24 HBP (P < 0.001). Both FHRvar% and Temp were significantly correlated with HBP (P < 0.001); however, these correlations were weak (Pearson’s r = −0.338 and −0.491, respectively). RI-UmbArt showed no significant variation across HBP (P = 0.711). An FHRvar% > 31.5% predicted parturition within 24 hours with a sensitivity of 65% and a specificity of 67%, whereas a Temp < 37.5°C predicted parturition with 69.6% sensitivity and 77.8% specificity. In conclusion, although FHRvar% and maternal body temperature are influenced by the proximity of parturition, they may not be reliable predictors of parturition timing, while RI-UmbArt appears to remain unchanged close to delivery.

Abstract in English:

Abstract During equine semen cryopreservation, most of the seminal plasma is removed, making sperm more susceptible to oxidative stress. This study evaluated the effect of resveratrol supplementation on the quality of frozen-thawed equine sperm. Semen from ten stallions was frozen using a control INRA 96 extender and extenders supplemented with 5-, 10-, 100-, and 150- µM resveratrol. Post-thaw evaluations included motility, kinematic parameters, morphology, plasma and acrosomal membrane integrity, mitochondrial potential, lipid peroxidation, nitrite, hydrogen peroxide, malondialdehyde levels, total reactive oxygen species (ROS), chromatin protamine deficiency, chromatin condensation, sperm binding to bovine oviduct explants, and gene expression of apoptosis-related genes such as B cell lymphoma 2 (BCL2) and BCL2-associated X (BAX), mitochondrial ROS modulator 1 associated with mitochondrial ROS production (ROMO1), sperm acrosome-associated 3 related with sperm binding capacity to the zona pellucida (SPACA3), and DNA damage repair gene 8-oxoguanine DNA glycosylase 1 (OGG1). Data were analyzed by ANOVA and Tukey test (P < 0.05). The 10 µM resveratrol treatment significantly increased sperm motility, mitochondrial activity, SPACA3 expression, and the number of sperm bound to oviduct explants compared to the control. Additionally, 10 µM resveratrol reduced total ROS, ROMO1, and BAX gene expression, indicating reduced oxidative stress and apoptosis. In conclusion, 10 µM resveratrol supplementation improved sperm metabolic activity, enhanced oviduct binding capacity, and demonstrated antioxidant and anti-apoptotic effects. Thus, incorporating resveratrol into freezing extenders could be a promising strategy to improve the fertilizing capacity of equine sperm in artificial insemination programs.

Abstract in English:

Abstract This study aimed to investigate one- year- old male rat sensitivity to fetal programming effects of subnutrition during gestation and lactation. Thirty primiparous female 3 month old Wistar rats were all mated by the same male. Pregnant females were organised in two experimental groups: control (CG n= 15; ad libitum food access) and restricted group (RG n= 15; food intake 50% of the control group). Morphometric and immunohistochemical techniques were employed to determine the number of Sertoli cells and both the distribution and relative abundance of androgen receptor in Sertoli, Leydig, and myoid cells. Additionally, the proportions of proliferating and apoptotic cells were analyzed. Testosterone concentration was also measured in blood serum and determined by a direct solid-phase radioimmunoassay. Our findings indicate that nutritionally restricted animals at early developmental stages exhibited reduced body weight (CG 592,9±33,4*** vs RG 527,5±23,5), testicular weight (CG 1,82±0,05*** vs RG 1,69±0,06), and body length (CG 47,2±0,7*** vs RG 45,1±1,6). We also observed in the same experimental group a lower number of Sertoli cells both per cross section of the seminiferous tubule (CG 23,4±0,32*** vs RG 21,8±0,34) and total per testicle (CG 134,6±24,9 x 104* vs RG 111,4±14,4 x 104). We found no treatment effect on the volume density of the testicular interstitium. No differences were observed between the groups in the proportion of proliferating and apoptotic cells. Finally, undernourished animals exhibited higher concentrations of testosterone in blood serum (CG 2,90 ± 1,51* vs RG 5,25 ± 3,53), and their myoid cells demonstrated increased expression of androgen receptors. In conclusion, our findings suggest that undernutrition during early life stages fetally programs the rat, negatively affecting its body development, altering testosterone production and testicular histophysiology in adults older than one year of age.

Abstract in English:

Abstract Understanding diseases that affect the male reproductive system of dogs and cats is important for improving their health and quality of life. Imaging techniques, such as ultrasound and X-rays, play a fundamental role in the evaluation of this system. They help veterinarians detect problems in the testicles, prostate, and other reproductive organs of dogs and cats. In recent years, advanced ultrasound methods, such as Doppler, elastography, and contrast-enhanced ultrasound, have become more accessible and allow earlier and more accurate diagnosis. Although definitive diagnosis of neoplastic lesions depends on cytological or histopathological examinations, radiography and advanced ultrasonography contribute significantly to early detection and malignancy characterization. This literature review explores the main imaging techniques used in the investigation of malignant lesions in the male reproductive tract of dogs and cats, namely radiography, B-mode and Doppler ultrasonography, elastography, and contrast-enhanced ultrasonography (CEUS). The goal is to help veterinarians make better decisions and improve care for their patients. The integration of these modalities has become well established in human medicine and shows growing applicability in veterinary practice, allowing for real-time, non-invasive assessment of the testes, prostate, penis, and scrotal structures. The compiled data highlight the potential of combining different imaging modalities to improve diagnostic accuracy and provide clinical and surgical support in the management of malignant lesions affecting the male reproductive tract in dogs and cats.

Abstract in English:

Abstract Pregnancy losses represent one of the main economic problems in cattle farming, where up to half of these losses can be associated with infectious diseases. Early identification of risk factors is essential to prevent reproductive and improve productivity in both beef and dairy systems. However, there are still a few studies in literature that relate etiological agents and the moment of gestation in which these reproductive failures occur. Embryonic and fetal losses vary widely across studies due to differences in diagnostic methods, herd management, pathogen exposure, and environmental conditions. This review summarizes the current scientific evidence on the intensity of pregnancy loss in cattle caused by infectious agents, relating to the most affected gestational stages and the most relevant pathogens. The main etiological agents identified were Neospora caninum, bovine viral diarrhea virus (BVDV), bovine herpesvirus type 1 (BoHV-1), Leptospira spp. and Campylobacter fetus. These infections compromise the reproductive efficiency of herds, causing infertility, embryonic mortality and abortions. Neospora caninum was the main agent associated with pregnancy losses, with abortions reported between the third and ninth months of gestation. BVDV was the second most frequently associated agent. Most pregnancy losses occurred between the second and third thirds of gestation, which makes early diagnosis of reproductive failures and the adoption of effective preventive measures difficult. The intensity and frequency of losses varied according to the agent involved, the geographic region and the type of production system. The findings of this review reinforce the need for continuous reproductive monitoring, especially with the use of pregnancy diagnostics at the end of the breeding season, in addition to the implementation of efficient biosecurity programs on properties.

Abstract in English:

Abstract This study assessed the histopathological and functional consequences of single bilateral intratesticular (InT; 200, 20, and 10 mg) and intraepididymal (InE; 50, 5, and 2.5 mg) eugenol administration in Wistar rats. Animals were monitored for up to 60 days, and testicular and epididymal tissues were examined for morphological alterations and sperm motility impairment. Both administration routes induced marked structural damage to the male reproductive tract. InT application led to progressive degeneration of the seminiferous epithelium, tubular atrophy, interstitial fibrosis, and focal mineralization, accompanied by reductions in both Leydig cell volumetric proportion and nuclear volume, hallmarks of impaired spermatogenesis and disrupted lumicrine signaling. In contrast, InE administration caused epithelial necrosis, intraluminal cellular debris accumulation, fibrotic remodeling, and ductal occlusion, ultimately leading to complete loss of sperm motility due to impaired maturation and obstructed transport. Although no overt systemic toxicity was observed, the findings indicate that local eugenol delivery exerts direct cytotoxic effects and promotes irreversible tissue remodeling. These results highlight eugenol’s potential as a chemical sterilant and reinforce the need for further studies to evaluate the reversibility of reproductive damage, inflammatory sequelae, and interspecies variability in toxicological responses.

Abstract in English:

Abstract This study evaluated reproductive performance of gilts classified as in anestrus in a batch farrowing system. Thirty-three gilts not expressing estrus within 40 days post-arrival were treated with chorionic gonadotropins, with blood collected for progesterone (P4) analysis on the same day. Thirteen gilts expressed estrus within 7 days, and 12 were inseminated (232.8 ± 2.1 days old), with 11 farrowing (91.7%; 14.2 ± 0.83 total piglets). Nineteen gilts had P4 ≤ 2.6 ng/mL at treatment; among the 20 non-responders, 10 had P4 > 2.6 ng/mL. A strong association was observed between P4 levels (≤ 2.6; > 2.6 and < 19; ≥ 19 ng/mL) and the responsiveness of gilts to gonadotropin treatment (P < 0.01; Cramér’s V = 0.63), with greater responsiveness in gilts with P4 levels ≤ 2.6 ng/mL. Non-responsive gilts (n = 20) received Altrenogest for 10 – 11 days, with 17 showing estrus within 10 days and 15 farrowing (88.2%; 14.3 ± 0.84 total piglets). Estrus detection failures and silent heat likely caused misdiagnosis. Gonadotropin, with or without Altrenogest, reduced culling ~8-fold, allowing 41–58% of gilts to reach at least the 3rd farrowing.