Animal Reproduction最新文献

{"title":"Influence of age range of dairy Gir cows on the composition of colostrum and milk, and on calves' passive immunity transfer.","authors":"João Vitor Menezes Lopes, Maria Claudia Pereda Francischini, Beatriz Melo Justo, Viviani Gomes, Camila Infantosi Vannucchi","doi":"10.1590/1984-3143-AR2025-0133","DOIUrl":"10.1590/1984-3143-AR2025-0133","url":null,"abstract":"<p><p>Colostrogenesis and lactogenesis influenced by age require further understanding in Zebu herds, due to the longevity of breeding cows. Thus, we aimed to compare colostrum and milk physicochemical and proteinogram of Dairy Gir cows and calves' passive immunity transfer by grouping 28 cows and their calves by maternal age: Young (n=6; aged 24-36 months), Adult (n=15; 37-91 months) and Senior (n=7; 96-137 months) groups. Colostrum and milk were collected at first milking (immediately after calving), transition milk (3^rd milking, after 24h of calving) and full milk (10^th milking, after 5 days of calving) for analysis of density, total solids, pH, immunoglobulin (IgG) and proteinogram (lactoferrin, albumin, heavy and light chain IgG, β-lactoglobulin and α-lactalbumin). Calves' blood was collected after 3 days of birth to evaluate serum total solids, total protein, liver profile, light and heavy chain IgG. Data were statistically analyzed by LSD Test at P<0.05. Young Group had higher (<i>P</i><0.05) colostrum total solid and density compared to Senior Group. Transition milk of young cows had lower (<i>P</i><0.05) pH than seniors. Calves of senior cows presented higher (<i>P</i><0.05) serum albumin than young and adult. Young cows had IgG decrease from colostrum to transition milk, whereas adult cows presented fall (<i>P</i><0.05) of IgG throughout milking. In conclusion, age of Dairy Gir cows does not affect colostrum and milk immunological quality, nor calves' immunity transfer. However, it determines protein composition and dynamic changes, especially in young and senior cows.</p>","PeriodicalId":7889,"journal":{"name":"Animal Reproduction","volume":"23 3","pages":"e20250133"},"PeriodicalIF":2.3,"publicationDate":"2026-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13286537/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148306540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reproductive performance of a semi-automated insemination system technology in sows.","authors":"Kebb Borstnez, Janine Camargo, Maiko Giorgi Philippe, Jean Carlo Volpato Faccin, Vanessa Peripolli, Ivan Bianchi, Ricardo Zanella, Mariana Groke Marques","doi":"10.1590/1984-3143-AR2025-0146","DOIUrl":"10.1590/1984-3143-AR2025-0146","url":null,"abstract":"<p><p>Artificial insemination (AI) is a key biotechnology applied to disseminate superior genetics; however, its success depends on skilled labor to ensure accurate and consistent execution. A semi-automated insemination system (SAIS), capable of controlling semen deposition and reproducing the pressure of natural mating, can align AI procedures more closely with the sow's physiological responses. The objective of this study was to evaluate whether the use of SAIS in post-cervical AI can improve reproductive efficiency in sows. A total of 449 females were inseminated, with 228 sows assigned to SAIS and 221 to the conventional method (CONV). Groups were balanced for parity, body condition, inseminator, and boar distribution. Sperm quality during storage did not differ between treatments. However, significant differences emerged during AI procedures: the SAIS group required less time to perform AI (18.60 ± 5.65 vs. 22.52 ± 12.38 seconds; P < 0.0001) and presented a lower incidence of semen backflow after AI (43.28% vs. 66.15%; P < 0.0001). The backflow negatively affected conception rate (P = 0.0342), although it did not influence total or live-born piglet numbers. Regarding reproductive performance, conception and farrowing rates were similar between groups. Nevertheless, females inseminated with SAIS have a higher total number of piglets born (16.97 ± 3.38 vs. 15.70 ± 3.91; P = 0.0027) and more live-born piglets (15.79 ± 3.3 vs. 14.46 ± 3.6; P = 0.0016) compared with CONV. Since backflow was not associated with litter size, this improvement cannot be attributed solely to reduced reflux. Instead, factors such as more standardized semen deposition and lower variability between inseminations may have contributed to this improvement. In conclusion, SAIS proved to be a practical and advantageous tool for AI in sows. Its use reduced time, decreased backflow, and increased litter size, representing a promising strategy to enhance efficiency in commercial herds.</p>","PeriodicalId":7889,"journal":{"name":"Animal Reproduction","volume":"23 3","pages":"e20250146"},"PeriodicalIF":2.3,"publicationDate":"2026-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13411999/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148617993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of resveratrol supplementation to equine sperm during semen cryopreservation.","authors":"Natália de Castro Alves, Marina Morra Freitas, Jade Raquel Dias Farias, Cesar Lopes Horta, José de Oliveira Carvalho, Olindo Assis Martins-Filho, Márcio Sobreira Silva Araújo, Ângela Quintão Lana, Guilherme Mattos Jardim Costa, Fernanda Radicchi Lobato de Almeida, Erica Azevedo Costa, Monique de Albuquerque Lagares","doi":"10.1590/1984-3143-AR2025-0107","DOIUrl":"10.1590/1984-3143-AR2025-0107","url":null,"abstract":"<p><p>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 (<i>P</i> < 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.</p>","PeriodicalId":7889,"journal":{"name":"Animal Reproduction","volume":"23 2","pages":"e20250107"},"PeriodicalIF":2.3,"publicationDate":"2026-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13286545/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148306577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Subnutrition during gestation and lactation affects testicular development, serum testosterone concentration and androgen receptor expression in myoid cells of mature rats.","authors":"Patricia Genovese, Emiliano Herrera, Martín Duque, Andrea Fernandez, Alejandro Bielli","doi":"10.1590/1984-3143-AR2025-0119","DOIUrl":"10.1590/1984-3143-AR2025-0119","url":null,"abstract":"<p><p>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; <i>ad libitum</i> 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.</p>","PeriodicalId":7889,"journal":{"name":"Animal Reproduction","volume":"23 2","pages":"e20250119"},"PeriodicalIF":2.3,"publicationDate":"2026-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13286544/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148306556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Applicability of fetal heart rate variation, umbilical artery resistivity index and maternal body temperature for predicting imminent parturition in bitches.","authors":"Diego Rodrigues Gomes, Diana Villa Verde Salazar, Denise Jaques Ramos, Camila Silveira Stanquini, Tamiris Disselli, Luiz Paulo Nogueira Aires, Stéfany Tagliatela Tinto, Mariana Ambroso Adib Donato Henriques, Alois Foltran Müller, Ricardo Andres Ramirez Uscategui, Adriano Bonfim Carregaro, Marcus Antônio Rossi Feliciano","doi":"10.1590/1984-3143-AR2025-0103","DOIUrl":"10.1590/1984-3143-AR2025-0103","url":null,"abstract":"<p><p>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.</p>","PeriodicalId":7889,"journal":{"name":"Animal Reproduction","volume":"23 2","pages":"e20250103"},"PeriodicalIF":2.3,"publicationDate":"2026-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13286526/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148306734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of lauric acid supplementation on bovine oocyte maturation, IVF embryo development, and stress protection during IVM.","authors":"Nguyen Duc Truong, Do Thi Kim Lanh, Nguyen Thi Ngoc Anh, Nguyen Hoai Nam, Bui Van Dung, Nguyen Van Thanh","doi":"10.1590/1984-3143-AR2025-0095","DOIUrl":"10.1590/1984-3143-AR2025-0095","url":null,"abstract":"<p><p>This study investigated the effects of lauric acid (LA) supplementation during <i>in vitro</i> 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 <i>in vitro</i> 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.</p>","PeriodicalId":7889,"journal":{"name":"Animal Reproduction","volume":"23 2","pages":"e20250095"},"PeriodicalIF":2.3,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13142084/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147832384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Infectious causes of pregnancy loss in cattle: a review of loss intensity and major reproductive pathogens involved.","authors":"Rodrigo de Morais, Giovanna Meireles Borges, Moyses Dos Santos Miranda, Luiz Francisco Machado Pfeifer, Rinaldo Batista Viana, Bruno Moura Monteiro","doi":"10.1590/1984-3143-AR2025-0064","DOIUrl":"10.1590/1984-3143-AR2025-0064","url":null,"abstract":"<p><p>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 <i>Neospora caninum</i>, bovine viral diarrhea virus (BVDV), bovine herpesvirus type 1 (BoHV-1), <i>Leptospira</i> spp. and <i>Campylobacter fetus</i>. These infections compromise the reproductive efficiency of herds, causing infertility, embryonic mortality and abortions. <i>Neospora caninum</i> 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.</p>","PeriodicalId":7889,"journal":{"name":"Animal Reproduction","volume":"23 2","pages":"e20250064"},"PeriodicalIF":2.3,"publicationDate":"2026-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13142087/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147832400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sustained multi-year contraceptive efficacy of single-dose GonaCon in synanthropic female capybaras.","authors":"Derek Andrew Rosenfield, Cristiane Schilbach Pizzutto","doi":"10.1590/1984-3143-AR2025-0142","DOIUrl":"10.1590/1984-3143-AR2025-0142","url":null,"abstract":"<p><p>Capybaras (<i>Hydrochoerus hydrochaeris</i>) 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 <i>Rickettsia rickettsii</i> zoonosis transmitted by <i>Amblyomma sculptum</i> 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; <i>p</i> < 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 (<i>p</i> < 0.005; Cohen's <i>d</i> > 1.5). Histological analysis validated HPG axis disruption, revealing significantly lower ovarian weights (<i>p</i>=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; <i>p</i><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.</p>","PeriodicalId":7889,"journal":{"name":"Animal Reproduction","volume":"23 2","pages":"e20250142"},"PeriodicalIF":2.3,"publicationDate":"2026-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13142086/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147832423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cryopreservation toxicity and morphological outcomes in <i>Piaractus brachypomus</i> oocytes and embryos.","authors":"Melanie Digmayer, Darci Carlos Fornari, Lis Santos Marques, Jayme Aparecido Povh, Ricardo Pereira Ribeiro, Eduardo Thomé Nicoleti, Leonardo Queiroz Alencar, Louise Nex Spica, Tiantian Zhang, Danilo Pedro Streit","doi":"10.1590/1984-3143-AR2025-0080","DOIUrl":"10.1590/1984-3143-AR2025-0080","url":null,"abstract":"<p><p>This study evaluated the toxicity of cryoprotectants and the performance of low-rate freezing protocols for oocytes and embryos of <i>Piaractus brachypomus</i>, 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 <i>ex situ</i> germoplasm conservation approaches for <i>P. brachypomus</i> and other Neotropical species.</p>","PeriodicalId":7889,"journal":{"name":"Animal Reproduction","volume":"23 2","pages":"e20250080"},"PeriodicalIF":2.3,"publicationDate":"2026-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13142085/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147832775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of donor breed and season of year on <i>in vitro</i> beef embryo production and recipient pregnancy rate.","authors":"Brenda Matos Fernandes, Gustavo Pereira Cadima, Natani Silva Reis, Ricarda Maria Dos Santos","doi":"10.1590/1984-3143-AR2025-0042","DOIUrl":"10.1590/1984-3143-AR2025-0042","url":null,"abstract":"<p><p>Approximately 85% of embryos produced in Brazil are <i>in vitro</i> (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 <i>vs</i>. Senepol) and the seasons of year (Dry <i>vs</i>. 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.</p>","PeriodicalId":7889,"journal":{"name":"Animal Reproduction","volume":"23 2","pages":"e20250042"},"PeriodicalIF":2.3,"publicationDate":"2026-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13075774/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147687888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}