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Background: Studying how the bull sharks aggregate and how they can be driven by life history traits such as reproduction, prey availability, predator avoidance and social interaction in a National Park such as Cabo Pulmo, is key to understand and protect the species. Methods: The occurrence variability of 32 bull sharks tracked with passive acoustic telemetry were investigated via a hierarchical logistic regression model, with inference conducted in a Bayesian framework, comparing sex, and their response to temperature and chlorophyll. Results: Based on the fitted model, occurrence probability varied by sex and length. Juvenile females had the highest values, whereas adult males the lowest. A strong seasonality or day of the year was recorded, where sharks were generally absent during September-November. However, some sharks did not show the common pattern, being detected just for a short period. This is one of the first studies where the Bayesian framework is used to study passive acoustic telemetry proving the potential to be used in further studies.

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Up to now, the definitive conclusion of the positive effects of rapid transient thawing at higher temperatures for shorter durations has not been obtained yet and is still under discussion due to some contradictory findings and limited assessment of post-thawed parameters. The purpose of the current study was to evaluate the effectiveness of rapid thawing in water at 70 °C by using various post-thawed parameters of frozen bull spermatozoa. Experiment 1, monitoring the change of temperature inside frozen bull straw thawed in water at different temperatures. Experiment 2, evaluation of various post-thawed characteristics of frozen bull spermatozoa thawed in water at different temperatures by using a computer-assisted sperm analysis, flow cytometry and immunocytochemistry. The time it took for the temperature inside the straw to warm up to 15 °C was nearly twice as faster when the straw was thawed in 70 °C water compared with 39 °C. Although there were differences among bulls, viability, motility, and mitochondrial membrane potential of spermatozoa thawed at 70 °C for 8 seconds and stabilized at 39 °C for 52 seconds were significantly higher than those of controls (thawed at 39 °C for 60 seconds) at 0 and 3 h after thawing. Just after thawing, however, there were no differences in acrosome integrity and distribution of phospholipase C zeta1, whereas mitochondrial reactive oxygen species production was significantly lower in spermatozoa thawed at 70 °C. From these results, we conclude that rapid thawing at 70 °C and then stabilization at 39 °C significantly improves viability, motility and mitochondrial health of bull spermatozoa rather than conventional thawing at 39 °C. The beneficial effect of rapid transient thawing could be due to shorter exposure to temperatures outside the physiological range, consequently maintaining mitochondrial health.

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The aim of this study was to investigate the relationship between age, scrotal circumference, postweaning weight and semen quality in Nellore and Caracu bulls selected for postweaning weight. Data from the andrological evaluation of 836 bulls born between 2000 and 2019, including 583 Nellore animals (Bos indicus) and 253 Caracu animals (Bos taurus), were used. The bulls were divided into categories of age at the time of assessment: category 1 consisted of animals aged 20 to 23 months (22 ± 0.76 months, 518 ± 94.17 kg), category 2 consisted of animals aged 24 to 35 months (30 ± 4.42 months, 679 ± 137.19 kg), and category 3 consisted of animals ≥ 36 months (60 ± 14.12 months, 907 ± 161.73 kg). The statistical model included the effects of breed, age category, date of semen collection, and breed x age category interaction. Heritability estimates for scrotal circumference at 13 months of age (SC1year) and semen quality traits were obtained for the sample of Nellore animals. Most semen quality traits improved with increasing age in both Nellore and Caracu animals. High heritability was observed for SC1year (0.45), while sperm motility, vigor, turbulence, and major, minor and total sperm defects exhibited low heritability (0.11, 0.019, 0.047, 0.017, 0.017 and 0.019, respectively). Spearman correlations of breeding values for postweaning weight (W378) and SC1year with the semen quality traits were low. Nellore and Caracu bulls have similar semen quality that improves with increasing age. In the Nellore breed, the heritability of SC is high, while semen quality traits exhibit low heritability. Selection for higher postweaning weight does not phenotypically affect the semen quality of bulls at breeding age.

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ABSTRACT This study aimed to evaluate the addition of different concentrations of IGF-I and insulin to egg yolk-based extender to improve bovine semen cryopreservation. Two experiments were developed to evaluate the effects of the additives in two commercial extenders, Botubov® (Experiment 1) and Triladyl® (Experiment 2), both with the same design. Three ejaculates from four bulls (n = 12) were used. Each ejaculate was divided into seven equal fractions for dilution (60x106 spermatozoa/mL) in the following treatments: CON: extender only; IGF100: IGF-I 100ng/mL; IGF200: IGF-I 200ng/mL; INS150: insulin 150µUI/mL; INS200: insulin 200µUI/mL; ASS1: IGF-I 100ng/mL + insulin 150µUI/mL; ASS2: IGF-I 200ng/mL + insulin 200µUI/mL. Semen was cryopreserved by an automated system. Post-thawed sperm were evaluated regarding motility by CASA (Computer-assisted sperm analysis), and membranes by fluorescent probes (H342, PI, FITC-PSA and JC-1). For Botubov® extender, INS150 was more efficient in preserving total and progressive motility, VCL, BCF, plasma and mitochondrial membranes. A similar response was seen when insulin was added to the Triladyl® extender, INS150 was more efficient in preserving sperm motility, plasma membrane integrity and mitochondrial potential. Thus, the addition of insulin 150µUI/mL, regardless of the composition of the extender, contributes to better preserving bovine sperm from the cryopreservation effects.

RESUMO Este estudo teve o objetivo de avaliar a adição de diferentes concentrações de IGF-I e insulina a diluidores, à base de gema de ovo, para melhorar a criopreservação do sêmen bovino. Dois experimentos foram desenvolvidos para avaliar os efeitos dos aditivos em dois diluidores comerciais: Botubov® (Experimento 1) e Triladyl® (Experimento 2), ambos com o mesmo delineamento. Foram utilizados três ejaculados de quatro touros (n=12). Cada ejaculado foi dividido em sete frações para diluição (60x106espermatozoides/mL), nos seguintes tratamentos: CON: somente diluidor; IGF100: 100ng/mL de IGF-I; IGF200: 200ng/mL de IGF-I; INS150: 150µUI/mL de insulina; INS200: 200µUI/mL de insulina; ASS1: 100ng/mL de IGF-I + 150µUI/mL de insulina; ASS2: 200ng/mL de IGF-I + 200µUI/mL de insulina. O sêmen foi criopreservado por sistema automatizado. Após a criopreservação, o sêmen foi avaliado quanto à motilidade espermática por CASA e quanto às membranas espermáticas (plasmática, acrossomal e mitocondrial) por sondas fluorescentes (H342, PI, FITC-PSA e JC-1). Para o diluidor Botubov®, INS150 foi mais eficiente em preservar motilidades total e progressiva, VCL, BCF, integridade da membrana plasmática e potencial mitocondrial. Resposta semelhante foi observada quando a insulina foi adicionada ao diluidor Triladyl®, INS150 foi mais eficiente na preservação da motilidade, integridade das membranas e potencial mitocondrial quando comparado aos demais grupos. Assim, a adição de 150µUI/mL de insulina aos diluidores, independentemente da composição, contribui para melhor criopreservação dos espermatozoides bovinos.

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Three experiments were designed to evaluate the effects of conventional and sexed-semen on reproductive performance of dairy females detected in estrus. In Exp. 1, 978 lactating Holstein cows and 116 Holstein heifers were used. Cows or heifers were randomly assigned to receive conventional (CONV) or sexed (SEXD) semen on day 0 of a TAI protocol. The TAI was performed using commercial CONV or SEXD frozen-thawed semen from the same 6 Holstein bulls, and SEXD semen was sexed through fluorescence cytometry. In Exp. 2, 390 lactating Holstein × Gir dairy cows and 344 Holstein × Gir heifers were used. Cows and heifers were randomly assigned to receive CONV or SEXD semen on day 0 with frozen-thawed semen from 5 Holstein × Gir bulls. The SEXD was sorted through the Sexcel™ methodology. In Exp. 3, 789 primiparous lactating Holstein cows were enrolled. Cows were randomly assigned to receive CONV or SEXD semen from 5 Holstein bulls, and the SEXD semen was sexed using the same semen allocation methodology described in Exp. 2. All data were analyzed using SAS. Regardless of the experiment, no treatment × bull interaction was observed for any of the variables analyzed herein (P ≥ 0.20). In Exp. 1, multiparous cows assigned to CONV had a greater P/AI vs. cohorts assigned to SEXD (P < 0.01) and a similar response tended to be observed for secundiparous cows (P = 0.10). No treatment effects were further observed when the effects of semen on day 60 P/AI were stratified by heat stress, milk yield, and CL at the beginning of the protocol. In Exp. 2, no P/AI differences between treatment were detected either on days 32 (P = 0.32) or 60 of pregnancy (P = 0.20). In Exp. 3, cows assigned to SEXD had reduced P/AI on day 32 (P = 0.03) and tended to have a reduced P/AI on day 60 of pregnancy (P = 0.06). No further treatment effects or interactions were observed herein (P ≥ 0.13). Overall P/AI of SEXD semen was 78% of the CONV (P < 0.01), but the variation of these results requires some attention. Moreover, an additional analysis was performed considering the median value of P/AI in bulls assigned to CONV and SEXD, and bulls that had a greater P/AI in CONV also had a greater P/AI in SEXD (P = 0.03). In summary, although not directly comparable, the sexing technologies herein provided similar results in heifers, but not in other categories (primiparous, secundiparous, and multiparous cows). Additionally, the P/AI of a sexed semen is associated to its performance on the conventional semen counterpart. Moreover, in the present experiment, no other parameters were shown to impact fertility of dairy females assigned to conventional or sexed-semen.

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Bovine leukemia virus (BLV) causes enzootic bovine leukosis, a persistent infection and the most important neoplastic disease in cattle. It is spread primarily by transferring infected lymphocytes through blood from carriers to healthy animals. The present study is aimed at determining the seropositivity of BLV in breeding bulls from Costa Rica and at detecting for the first time in the country BLV DNA in bull semen. Between May 2011 and August 2018, 379 blood and 133 semen samples were collected from bulls distributed in 118 farms. The serum was analyzed by an enzymatic immunoassay and the semen by polymerase chain reaction and sequencing. BLV seropositivity was 43.5% (165/379), while 64.4% (76/118) of the farms had positive reactors. Holstein (75.7%) and Jersey (73.0%) breeds showed the highest seropositivity. In addition, Bos taurus bulls (68.1%), older than seven years (50.0%), and those belonging to dairy farms (75.5%) had higher seropositivity compared to Bos indicus (17.7%), younger than seven years (42.2%), and those from beef farms (15.5%), respectively. Moreover, Bos taurus bulls had a higher risk of being seropositive than Bos indicus (OR = 3.4; 95% CI: 1.7-6.8). BLV DNA was found in one semen sample (2.5%; 1/40) from a seropositive bull. The importance of serum and molecular BLV screening in semen samples and the potential role of some risk factors associated with the disease, such as the bull's age, genotype, and type of livestock productive system, is argued in the present report.

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Beef production systems primarily use natural service (NS) for breeding. However, a significant number of bulls used for NS are subfertile, limiting the profitability of the cow-calf operations. Therefore, producers should select bulls based on breeding soundness evolutions (BSE) to ensure higher pregnancy rates. Several factors can affect the bull ability to pass a BSE. We hypothesize that calving date would be a factor that affects the bull probability of approval at the first BSE. For this purpose, a multivariate logistic regression in a dataset of 14,737 BSEs from young Nellore bulls was used. Correlations between calving date, biometrics, and semen traits were evaluated using Pearson's correlation coefficient. Our results demonstrated that the calving date affected the probability of approval at the first BSE (p < .05). Indeed, the variable that added more information to our model was the calving date, far more than the age group of the bulls according to Akaike's information criterion. Hence, bulls born on day 0 of the calving season have 1.26 more chances to be approved at the first BSE than bulls born 21 days later. This result highlights the importance of getting the dams of future bulls pregnant as soon as possible in the breeding season. In addition, the calving season should be no longer than 47 days to achieve 80% BSE approval in 20-22 months old Nellore bulls. The strongest correlation was with SC, which decreased as the calving date increased. Therefore, the calving date may be used as a predictor of the outcome of the first BSE in young bulls. In that way, the calving date can help seedstock producers to maximize efficiency in making crucial management decisions during the breeding and calving season including nutrition, reproductive, and culling.

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There were 463,000 head of beef cows in New Mexico as of January 1, 2021 (NASS, 2020), down roughly 4% from 2020 (NASS, 2019). Frequent drought often results in herd reduction and loss of valuable genetic progress. Bull selection is critical due to their influence on herd development. A survey was conducted to identify traits important to bull selection in New Mexico. Surveys were collected digitally (n = 83) and via the mail (n = 74). Responses were largely by cow/calf producers averaging 57 ± 1 years old with 24 ± 1 years' experience. Survey respondents represented 4,384,296 acres of private owned, private leased, and leased public rangeland and irrigated pasture meadow in New Mexico and surrounding states. Average cow/calf operation size was 294 ± 39 head and average bull herd size was 21 ± 3 head. Average price paid for a bull in the past 2 years was $3,981 ± 213. Physical characteristics, individual bull performance information, and genetic information are all important traits to New Mexico bull buyers; however, most producers (56%) indicated that structural soundness was the most important factor influencing their selection decisions. Amongst expected progeny differences (EPDs), New Mexico producers consider the calving ease direct (CED) and birth weight (BW) EPDS to be most important (40% and 35%, respectively). Producers also indicated that multitrait selection indexes used by the American Angus Association were important to their selection decisions, with the beef value ($B) and weaned calf value ($W) indexes being cited most often (35% and 31%, respectively). Elements important to bull purchase include the bull's sale preview (87%), body condition score (86%), feed efficiency/average daily gain information (85%), and actual scrotal circumference (82%). Following purchase of a new bull, most (60%) keep the bull separate from the cow herd until the following breeding season, while the remaining 40% of producers turn newly purchased bulls out within 30 days of purchase. Sixty eight percent of producers evaluate semen quality annually or prior to the start of the breeding season. Interestingly, 39% of producers indicated they used reproductive technologies like artificial insemination and synchronization of estrus while most (80%) test for trichomoniasis. The primary factor influencing culling decisions is age, followed by soundness and fertility.

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Testicular ultrasound enables the evaluation of changes in the testicular parenchyma. This study aimed to report the occurrence of hypoechogenic testicular alterations and their relationship with semen quality in five breeding buffaloes. Two buffaloes presented with hyperechoic points characteristic of fibrosis and anechoic density content between the parietal and visceral tunica. The two bulls without ultrasonographic changes showed higher average trajectory speed, linear velocity, curvilinear velocity, amplitude of lateral displacement of the spermatic head, total motility, progressive motility, fast speed, and acrosomal membrane values within the normal range. The number of spermatozoa with major and total defects was higher in the group of animals without alterations. The three buffaloes that presented with testicular alterations produced semen within established freezing standards.

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Although banned in several countries worldwide, dog fighting has remained a challenge, particularly on criminal investigation, recognition, and prosecution. Besides animal cruelty, dog fighting has been controlled mostly by criminal organizations and accompanied by illegal gambling and drug trafficking. While such competitions may be impaired by advances of legislation on animal welfare and media coverage, international organized crime has been migrating to less regulated and enforced countries. The case herein reported a flagrant dog fighting investigation in an international event involving 27 Pitbull dogs in Mairiporã, located 50 km outside São Paulo City, Brazil. An international network of dog fighting was revealed at the tournament, along with presence of organizers from USA, Mexico, and Peru. Proof was obtained on-site about other similar past and future competitions in other Latin American countries. Dogs were rescued, thoroughly examined for signs of animal cruelty, surveyed for potential diseases, and tested positive for visceral canine leishmaniasis. The process conducted by the state hearing resulted in the highest criminal sentence attributed to animal cruelty in Brazil to date, serving as jurisprudence for future prosecutions. Forensic veterinary medicine was essential in this case as a specialty for police and court assistance, leading to detailed and undeniable report of animal cruelty.

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Sperm routinary fitness evaluation is not sufficient to predict bull reproductive capacity as they present differences in fertility up to 40%. Among the defects which compromise spermatozoa functionality, new approaches consider the study of sperm chromatin, which is the core structure containing paternal genetic information. Sperm chromatin needs to be compacted to maintain the integrity of DNA, which occurs by binding nucleoproteins with high affinity to DNA. In the last stages of sperm maturation, chromatin is hyper-compacted by basic proteins called protamines in a process named protamination. In this review, we summarized intrinsic and extrinsic factors that are suggested to influence protamination in bull spermatozoa, considering old and new evidence from human and murine spermatozoa. Also, the current approaches to evaluate bull protamination and its relationship with fertility were described. Nevertheless, the physiological mechanisms of protamination are still poorly understood.

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Background and Aim: Lepidium meyenii Walp (Maca) is an herbaceous plant that grows in the Peruvian Andes and it has been widely used as a nutritional supplement and fertility enhancer and has been used in the treatment of a variety of diseases, such as rheumatism, respiratory disorders, and anemia. The most notable feature of Maca is its potent antioxidant capacity, which helps in the scavenging of free radicals and protection of cells from oxidative stress. This study aimed to evaluate the in vitro effect of Maca extract on thawed sperm cells from bulls. Materials and Methods: Three dilutions of 1, 10, and 100 mg/mL of Maca extract were incubated with frozen-thawed bovine semen and analyzed at 1, 3, and 24 h of exposure time, evaluating the activity of the extract on the DNA, motility, morphology, viability, integrity of the membrane and acrosome of spermatozoa. Results: The Maca extract improved the studied sperm parameters of motility, acrosome integrity, vitality, and DNA integrity of sperm cells at a concentration of 10 mg/mL, and at 1 mg/mL, an improvement was observed in the morphology and integrity of the membrane. However, the best activity of the Maca extract was observed on the DNA integrity of the sperm, which was effective at the three concentrations evaluated after 24 h of incubation. Conclusion: The results indicate that L. meyenii can help in maintaining spermatozoa cellular integrity after the frozen-thaw process, especially in the protection against DNA fragmentation. Therefore, Maca would be a feasible supplementation to protect sperm to maintain their fertile ability after thawing.

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Prediction of bull fertility is critical for the sustainability of both dairy and beef cattle production. Even though bulls produce ample amounts of sperm with normal parameters, some bulls may still suffer from subpar fertility. This causes major economic losses in the cattle industry because using artificial insemination, semen from one single bull can be used to inseminate hundreds of thousands of cows. Although there are several traditional methods to estimate bull fertility, such methods are not sufficient to explain and accurately predict the subfertility of individual bulls. Since fertility is a complex trait influenced by a number of factors including genetics, epigenetics, and environment, there is an urgent need for a comprehensive methodological approach to clarify uncertainty in male subfertility. The present review focuses on molecular and functional signatures of bull sperm associated with fertility. Potential roles of functional genomics (proteome, small noncoding RNAs, lipidome, metabolome) on determining male fertility and its potential as a fertility biomarker are discussed. This review provides a better understanding of the molecular signatures of viable and fertile sperm cells and their potential to be used as fertility biomarkers. This information will help uncover the underlying reasons for idiopathic subfertility.

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Neutrophil extracellular traps (NETs) play a key role in fertilisation by eliminating microorganisms and entrapping spermatozoa in the female reproductive tract (FRT). The deleterious effects of NETs on spermatozoa have been previously described; however, individual exposure to NET-derived components in bull spermatozoa has not been explored. The aim of this study was to evaluate the effects of the main NET-derived proteins, histone 2A (H2A), neutrophil elastase (ELA), myeloperoxidase (MPO), pentraxin 3 (PTX), cathepsin G (Cat-G), and cathelicidin LL37 (LL-37), at concentrations of 1, 10, and 30 µg/mL, on sperm parameters. Sperm were selected and incubated with different NET-derived proteins for 4 h. Membrane and acrosome integrity, lipoperoxidation, and membrane phospholipid disorders were also evaluated. Bovine polymorphonuclear neutrophil (PMN)/sperm co-cultures were evaluated by scanning electron microscopy and immunofluorescence. All NET-derived proteins/enzymes resulted in a reduction in membrane integrity, acrosome integrity, and lipoperoxidation at a concentration of 30 µg/mL. Bovine PMN/sperm co-cultures showed marked NET formation in the second hour. In conclusion, all NET-derived proteins/enzymes exerted cytotoxic effects on bull sperm, and this effect should be considered in future investigations on the uterine microenvironment and the advancement of spermatozoa in the FRT.

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Energy drink (ED) consumption has become a growing public health issue over the past few decades. Despite claims of being safe and beneficial, EDs have been linked to particularly fatal outcomes associated with the cardiovascular system which include atrial and ventricular arrhythmias, myocardial infarctions, cardiomyopathies, and sudden cardiac death. Large quantities of caffeine, taurine, sugars, and B-vitamins may be contributing to these outcomes by increasing the heart rate, blood pressure (BP), and contractility of the heart in addition to prolonging the QTc. There is still a substantial amount of unknown information on EDs that warrants more research and a dire need for age regulations, transparency of ingredients, clear labeling of adverse effects, and most importantly, education of consumers.

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The application of hydrotherapy is growing in the field of animal rehabilitation to improve strength, endurance, fitness, and range of motion, in addition to reducing pain. In the same way, land-based activity is recommended for various conditions, including hypertension, muscle atrophy, and obesity. There is a lack of studies that evaluate the safety of incremental exercise in American Pit Bull Terriers. This study assessed the influence of activity on underwater and dry land treadmills on the physiological parameters of dogs. In this regard, 12 adult, male, healthy, and untrained American Pit Bull Terriers were subjected to an incremental exercise test (IET) on the underwater treadmill (Group I) and the dry land treadmill (Group II). Heart rate (HR), respiratory rate (RR), rectal temperature (RT), systolic blood pressure (SBP), and electrocardiographic evaluation, were evaluated before activity (T0), immediately after (T1), 30 min after (T2), and 90 min after the end of exercise (T3), and plasmatic lactate concentrations were measured at T0, T1, and T2 time points. Results obtained were submitted to the Shapiro-Wilk test, ANOVA and Tukey's test, considering P<0.05. Water activity induced a reduction in RR (P=0.00674) in all examinations after the test on the underwater treadmill and proved to be more demanding than activity on the land treadmill, considering the presence of a deeper and slower RR. Exercise sessions in both groups did not elevate the lactate concentration. The IET can be performed safely on an underwater or dry land treadmill in healthy American Pit Bulls.

A hidroterapia apresenta crescente aplicação no ramo da reabilitação animal, com o intuito de aumentar a força, resistência muscular e amplitude de movimento articular, além de reduzir a dor e melhorar o condicionamento físico do paciente. Assim como a hidroterapia, a atividade desenvolvida em solo é indicada para diversas afecções, inclusive para pacientes hipertensos, com atrofia muscular ou com sobrepeso. São escassos os estudos que avaliam a segurança de testes incrementais em esteira aquática e em esteira seca em American Pit Bull Terriers. Este estudo teve como objetivo avaliar os efeitos da atividade em esteira aquática e em esteira seca sobre os parâmetros fisiológicos de cães. Para isto, cães da raça American Pit Bull Terrier (n=12) machos, adultos, saudáveis e não treinados foram submetidos a teste de esforço incremental (TEI) em hidroesteira com água (Grupo I) e sem água (Grupo II). A frequência cardíaca (FR), frequência respiratória (FR), temperatura retal (TR), pressão arterial sistólica (PAS) e avaliação eletrocardiográfica, foram aferidas antes da atividade (T0), imediatamente após (T1), 30 minutos após (T2) e 90 minutos após o exercício (T3), e a concentração plasmática de lactato foi dosada nos momentos T0, T1 e T2. Os resultados foram submetidos ao teste de Shapiro-Wilk, análise de variância (ANOVA) e pelo Teste de Tukey, considerando significativo o valor de P < 0.05. Houve diminuição da frequência respiratória (P = 0,00674) após a atividade em esteira aquática, que se mostrou mais exigente que a atividade em esteira terrestre, considerando a apresentação de padrão respiratório mais lento e profundo. As sessões de exercício em ambos os grupos não elevaram a concentração de lactato. O teste de esforço incremental em esteira aquática, ou em esteira seca, pode ser desenvolvido com segurança por cães American Pit Bull saudáveis.

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Prediction of bull fertility is critical for the sustainability of both dairy and beef cattle production. Even though bulls produce ample amounts of sperm with normal parameters, some bulls may still suffer from subpar fertility. This causes major economic losses in the cattle industry because using artificial insemination, semen from one single bull can be used to inseminate hundreds of thousands of cows. Although there are several traditional methods to estimate bull fertility, such methods are not sufficient to explain and accurately predict the subfertility of individual bulls. Since fertility is a complex trait influenced by a number of factors including genetics, epigenetics, and environment, there is an urgent need for a comprehensive methodological approach to clarify uncertainty in male subfertility. The present review focuses on molecular and functional signatures of bull sperm associated with fertility. Potential roles of functional genomics (proteome, small noncoding RNAs, lipidome, metabolome) on determining male fertility and its potential as a fertility biomarker are discussed. This review provides a better understanding of the molecular signatures of viable and fertile sperm cells and their potential to be used as fertility biomarkers. This information will help uncover the underlying reasons for idiopathic subfertility.(AU)

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A morfologia espermática é uma característica seminal que está associada à fertilidade e é, portanto, um componente importante na rotina do controle de qualidade em Centros de Coleta e Processamento de Sêmen (CCPS). É utilizada para caracterizar e quantificar os vários tipos de anormalidades nas células espermáticas do touro, usando preparação em montagem úmida para microscopia de Contraste de Interferência Diferencial (DIC), Contraste de Fase (CF) e Lâmina Corada (LC). O perfil da morfologia espermática permite a tomada de decisão sobre o aproveitamento ou descarte de um ejaculado para criopreservação e predizer a fertilidade de uma amostra de sêmen. Alterações no espermograma, com evidências do histórico e exame físico do touro, levam a interpretação da função testicular anormal, e consequentemente, ao diagnóstico, tratamento e prognóstico, se for o caso. As causas mais comuns de uma espermatogênese anormal nos touros incluem: termorregulação testicular anormal, desequilíbrios hormonais, estresse de manejo, ambiental e nutricional, efeitos de toxinas ou expressão de genes deletérios, além de defeitos de origem genética. Conhecendo-se a estrutura do espermatozoide, torna-se mais fácil a identificação das anormalidades espermáticas bem como a descrição das mesmas e uma melhor compreensão de sua origem.(AU)

Sperm morphology is a seminal trait that is associated with fertility and is therefore an important component of routine quality control in Semen Collection and Processing Centers (SCPC). It is used to characterize and quantify the various types of abnormalities in bull sperm cells, using wet mount preparation for Differential Interference Contrast (DIC), Phase Contrast (PC) and Slides Smear (SS) microscopy. The sperm morphology profile allows decision making on the use or disposal of an ejaculate for cryopreservation and predicts the fertility of a semen sample. Changes in sperm morphology may indicate that fertility may be impacted and therefore it is important to routinely monitor ejaculates. An abnormal spermogram with evidence from a history and physical examination of the bull can lead to the interpretation of abnormal testicular function, and consequently, to the diagnosis, treatment and prognosis, if any. The most common causes of abnormal spermatogenesis in bulls include: abnormal testicular thermoregulation, hormonal imbalances, management, environmental and nutritional stress, effects of toxins or expression of deleterious genes, in addition to defects of genetic origin. Knowledge in the structure of the sperm makes easier the identification of sperm abnormalities, as well as their description and provides a better understanding of their origin.(AU)

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A grande demanda por sêmen congelado para inseminação artificial no Brasil está ocasionando que criadores, programas genéticos, e centros de coleta e processamento de sêmen produzam touros cada vez mais jovens para doação de sêmen. A avaliação genômica é uma nova ferramenta para a seleção de touros jovens para os centros de coleta, porém, junto vieram os problemas na seleção de bons doadores de sêmen que muitas vezes não atingem a puberdade na idade desejada, principalmente na raça Nelore que é a mais importante para o mercado de inseminação no país. A maioria dos problemas com a produção de sêmen do touro jovem genômico podem ser resolvidos com o tempo, mas ainda ocasiona vários problemas não resolvidos. Os touros jovens genômicos da raça Nelore atingem a puberdade entre 13 a 16 meses e os touros jovens das raças Holandesa e Angus entre 10 a 12 meses de idade sendo que a maturidade sexual no geral é alcançada entre 18 a 24 meses quando passam a produzir sêmen rotineiramente e produzem grandes quantidades de unidades de sêmen criopreservado para uso na inseminação artificial. Este cenário ocasionará um problema para o mercado da inseminação artificial, com a demanda de mais touros com maturidade sexual.(AU)

The great demand for frozen semen in the artificial insemination in Brazil is causing breeders, genetic programs, and semen collection and processing centers to produce ever younger bulls for semen donation. The genomic evaluation is a new tool for the selection of young bulls for the collection centers, however, along came the problems in the selection of good semen donors that often do not reach puberty at the desired age, especially in the Nellore breed, the most important for the insemination market in the country. Most problems with genomic young bull semen production can be resolved over time, but there are still several unresolved problems. Young genomic Nellore bulls reach puberty between 13 to 16 months and young Holstein and Angus bulls between 10 to 12 months of age and sexual maturity is generally reached between 18 to 24 months when they start to produce semen routinely, so producing a large quantities of cryopreserved semen units for use in artificial insemination. This will cause a problem for the artificial insemination business where more sexually mature bulls will be needed.(AU)

Assuntos

RESUMO

ABSTRACT Myoglobin (Mb) is a sarcoplasmic heme protein present in muscle cells, which acts as a shortterm oxygen (O2) reserve in the muscle tissue. After slaughtering and exsanguination, Mb is the major pigment that provides the red color in meat. The concentration of Mb together with its redox state are two pivotal factors that determine meat color. The elevated pH of darkcutting beef can affect both physical and biochemical properties resulting in decreased oxygenation. The darkening observed in high ultimate pH (pHu) beef concerns meat processors as color is the initial attribute that impacts on the purchase. Thus, any atypical meat color (i.e., loss of brightness) reduces consumer interest in the product. Several studies have demonstrated that immunological castration is effective in preventing both aggressive behavior and undesirable darkcutting of bull meat. However, little information is available on the effects of processing techniques that limit the oxidation of ferrous iron (Fe2+), Mb or promote metmyoglobin (MMb) reduction in darkcutting beef. Because of the importance of color to fresh beef marketability, this review aimed at overviewing the significance of pHu in beef color and color stability and to discuss new alternatives for improving and assessing the beef color of darkcutting beef, especially in Nellore bulls and their crossbreds, which are widely used in beef cattle production in Brazil.