Acrobustitis-phimosis in bulls: postoplasty technique performed with the animals in a standing position.

Acrobustitis is the inflammation of the distal prepuce, which can lead to a narrowing of the preputial ostium due to stenosis or growth of fibrous tissue after an inflammatory reaction. This condition usually occurs in cattle with long prepuce, such as Zebu or Zebu's crossbreeds, leading the animal to Impotentia Coeundi, this condition is characterized by the bull's disability to copulate, that leads to lower herd fertility and consequent financial losses. Normally, corrective surgeries are performed on-farm and the animal is placed in a lateral recumbency. However, in some situations the animal is restrained with ropes and remains on the grass, dirt or even on uneven floors, which can cause neuropathies, bloat or hypoxia. Due to a series of complications that can occur in the postoperative period of surgery in the lateral recumbency, this article aims to describe the surgical technique for correcting acrobustitis with the animal in a standing position. Ten corrective surgeries for acrobustitis were performed in adult bulls between 4 and 8 years of age and predominantly of zebu or crossbreeds, with a total recovery of the animals for full reproductive activity.

Testicular alterations and semen quality in a selected group of breeding buffaloes.

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.

Impact of cryopreservation protocols (one- and two-step) on boar semen quality at 5 °C and post-thawing.

The two-step protocol (2 S) is currently used for boar semen cryopreservation. In this method, the cryoprotectant penetrant agents (CPAs) are added at 5 °C to reduce the toxicity of CPAs. An alternative is the one-step protocol (1 S), which is easier, cheaper, and reduces the necessity of equipment, but could increase the toxicity of CPAs. Currently, there are no studies that compared both protocols for boar semen cryopreservation. This experiment aimed to study the effect of cryopreservation protocol (1 S vs 2 S) on boar spermatozoa. In the one-step protocol, after centrifugation, the spermatozoa pellet was resuspended at 17 °C in the extender containing CPAs to achieve a concentration of 1 × 109 spermatozoa/mL and then submitted to cryopreservation. For the two-step protocol, the sperm pellet was resuspended in fraction A at 17 °C to achieve a concentration of 1.5 × 109 spermatozoa/ mL, and then allowed to cool to 5º C before fraction B with CPA was added to the sample to achieve a final concentration of 1 × 109 spermatozoa/mL and followed by freezing. The cryopreservation protocol did not impact total motility at 5 °C (1 S: 78.5 % vs 2 S: 79 %, p > 0.05). After thawing, the two-step protocol improved (p < 0.05) total (1 S: 18.2 % vs 2 S: 29.5 %) and progressive motility (1 S: 9 % vs 2 S: 15%). Further, the 2 S protocol increased (p < 0.05) the percentage of rapid spermatozoa (1 S: 8.7 % vs 2 S: 14.6 %) and spermatozoa with intact plasma and acrosomal membrane (IAIP) (1 S: 40.5 % vs 2 S: 61.5 %), and increased (p < 0.05) live sperm cells with high mitochondrial potential (MHIP) (1 S: 42.9 % vs 2 S: 60 %). The boar semen cryopreservation method (TRT) did not (p > 0.05) alter membrane lipid disorder, lipid peroxidation, and superoxide anion. Thus, the best method for boar semen cryopreservation is the two-step protocol.

Insights into the influence of canine breed on proteomics of the spermatozoa and seminal plasma.

This study aimed to characterize the proteome of spermatozoa and seminal plasma of 4 purebred dogs (Golden Retriever, Great Dane, Bernese Mountain Dog, and Maremmano-Abruzzese Sheepdog). The ejaculate of 13 dogs was collected, and sperm characteristics were subjectively evaluated. Seminal plasma and sperm cells were separated and prepared individually for mass spectrometry. Data were evaluated by univariate and multivariate statistical analysis. A total of 162 proteins were identified, 47 in spermatozoa, 109 in seminal plasma, and 6 in both samples. Serum albumin in spermatozoa and tubulin alpha-3E chain, acrosin binding protein, and tubulin alpha-3 chain in plasma seminal were statistically relevant. Serum albumin and acrosin binding protein improve the sperm capacitation, acrosome reaction, and seminal quality. The tubulin family proteins are related to structural cell organization and flagella movement, and their presence in seminal plasma may be related to sample handling. According to cluster formation, a high association was observed among Bernese Mountain Dog and Great Dane, Golden Retriever, and Maremmano-Abruzzese Sheepdog for sperm proteins. For seminal plasma proteins, Bernese Mountain Dog, Great Dane, and Maremmano-Abruzzese Sheepdog were related. Further studies on breed-specific proteins in the semen of purebred dogs need to be performed to clarify its fertility roles. SIGNIFICANCE: For the first time spermatozoa proteins of dogs are described. The comparison of spermatozoa and seminal plasma proteins of four purebred dogs were performed. These results supporting that differences in semen protein profile of different canine breeds exist, which can improve the biotechnologies of reproduction in this species.

Seminal Plasma Does Not Influence Canine Semen Stored at 5°C for Long-Term Conservation.

Seminal plasma has several components that protect the sperm cells and assist in the fertilization process. In contrast, the exact role carried out by seminal plasma during the cooling of canine semen remains controversial. Moreover, concerning the long estrus period, the possibility to store chilled semen at 5°C for more than 72 hours and maintain good sperm quality for additional inseminations could increase fertilization rates. Thus, this study aimed to evaluate the seminal plasma influence on quality and oxidative stress of the extended canine semen stored at 5°C for 7 days. Three ejaculate pools from eight healthy dogs were collected by digital manipulation of the penis. The sperm kinetics, sperm vitality (eosin/nigrosin stain), integrity of plasma and acrosomal membranes, morphology, superoxide and hydrogen peroxide production, mitochondrial potential, lipid peroxidation, and oxygen reactive species production (induced and spontaneous thiobarbituric acid [thiobarbituric acid reactive substances, TBARS] assay) were evaluated every 48 hours (M0, M48, M96, and M168) until 7 days (168 hours) in cooled extended (TRIS egg yolk) semen of dogs at 5°C with (+SP) or without (-SP) autologous seminal plasma. No statistical difference was found for sperm kinetics in cooled samples with +SP and -SP during the experimental time period, except for the progressive motility of +SP samples that was higher at M48 than M96 (p = 0.023). The seminal plasma did not influence any other evaluated sperm characteristics. Finally, our results demonstrated that the presence or lack of seminal plasma during cooling the semen of dogs does not influence sperm quality at 5°C. Moreover, the components of the semen extender may contribute to maintaining good sperm quality and low reactive oxygen species production during the long period of the dog's semen cooling, even after semen centrifugation.

Assessment of thawed sperm quality from feline species: Ocelot (Leopardus pardalis) and oncilla (Leopardus gutullus).

This study aimed to evaluate the cryopreservation effects on the semen of oncilla (Leopardus guttulus, n = 5, 15 ejaculates) and ocelot (Leopardus pardalis, n = 5, 17 ejaculates) and compare two extenders (commercial and non-commercial extender). An andrological exam was conducted (testicle measurements and penis evaluation), including semen collection by electroejaculation. After collection, the semen was assessed to volume, color, pH, sperm motility, vigor, sperm number in the ejaculate, viability, membrane integrity, and sperm morphology. Samples were centrifuged (300 g for 10 min) and pellet diluted in two extenders (TRIS/glucose/egg yolk and BotuCRIO®), packed into 0.25 mL French straws (20 × 106 spermatozoa/mL), equilibrated at 5 °C for 1 h (<0.5 °C/min), freezing in nitrogen vapor for 20 min. Thawing was achieved at 46 °C for 15 min. Thawed samples were evaluated to the same characteristics and ultrastructural analysis. There is no difference for extenders, but in ocelot the spermatozoa maintained higher quality after thawing. Major defects were increased in thawed samples, especially acrosome injuries, in both species. Semen contamination by urine was remarkable to oncilla (53% of the ejaculates) which can have reduced sperm cryoresistance of this species. Ultrastructural analysis endorsed morphological analysis under light microscopy and identified cells with acrosome vesiculation. In conclusion, the spermatozoa of ocelot were more cryoresistent and the extender commercial and non-commercial were suitable for their cryopreservation. Other extenders should be investigated for oncilla.

Cholesterol-Loaded Cyclodextrin Addition to Skim Milk-Based Extender Enhances Donkey Semen Cooling and Fertility in Horse Mares.

The present study aimed to compare semen parameters and fertility of cooled donkey semen extended in a commercially available skim milk (SKM) based extender and the same extender with cholesterol-loaded cyclodextrin (SKM-CLC). In Experiment 1, thirty-five ejaculates from seven jacks were split in SKM and SKM-CLC, extended at 50 million sperm/mL and stored at 5°C for 48 hours. Total motility (TM), progressive motility (PM), percentage of sperm with rapid motility (RAP) were assessed with CASA. Plasma membrane stability (PMS), and high mitochondrial membrane potential (HMP) were assessed with the combination of Yo-Pro and MitoStatusRed with flow cytometry. Semen was assessed before (0), 24 and 48h after cooling. In Experiment 2, two estrous cycles of 15 mares were used for fertility assessment. Mares were examined every other day by transrectal ultrasonography and had ovulation induced with 250 µg of histrelin acetate when a ≥35 mm follicle was first detected. Mares were randomly inseminated with semen obtained from one jack. Semen was extended in either SKM or SKM-CLC and cooled-stored for 24 hours. Pregnancy diagnosis was carried out 15-day post-ovulation. Data were analyzed with a mix model and Tukey's as posthoc and logistic regression model. Significance was set at P ≤ .05. There were no differences in TM, PM, RAP, PMS, and HMP for semen extended in either extender immediately before cooling (P > .05). There was a reduction in TM, PM, RAP, PMS, and HMP overtime across groups (P < .05); however, semen extended with SKM-CLC had superior TM, PM, RAP, PMS, and HMP than semen extended in SKM at 24- and 48-hours post-cooling (P < .05). Mares bred with semen extended in SKM had a lower conception rate (13%, 2/15 cycles) than cycles bred with SKM-CLC (47%, 7/15 cycles; P < .05). In conclusion, incorporating CLC into SKM extender improved cooling ability and fertility of donkey semen in horse mares. It remains to be determined if similar results can be obtained in clinical practice with mares and jennies.

Inflammatory response of miniature horses subjected to open and half-closed orchiectomy techniques.

BACKGROUND: This study aimed to evaluate the inflammatory response of miniature horses subjected to open and half-closed orchiectomy by physical examination, blood cell count, peritoneal fluid evaluation, total plasma protein, fibrinogen, and serum amyloid A (SAA) concentrations. METHODS: Thirteen male healthy miniature horses were divided into two groups, according to the surgical approach: half-closed technique (HCT) and open technique (OT). The HCT group was subjected to ligation of the spermatic cord followed by its sharp incision, and closure of the vaginal tunic, and the OT group was only submitted to cord ligation. Prior to, and at 1, 2, 3 and 5 days after the surgery, a general and specific physical examination, blood cell counts, total plasma protein, peritoneal fluid evaluation, fibrinogen, and SAA concentrations were performed. RESULTS: Higher postoperative perilesional oedema, rectal temperature, and fibrinogen were observed in the HCT group. Groups did not differ as to SAA concentrations. The evaluated local and systemic inflammatory profile demonstrated that, as expected, surgery resulted in inflammation in both groups. CONCLUSIONS: The group subjected to the HCT showed a more intense and lasting inflammatory response. However, despite the different postoperative inflammatory profiles, both groups presented a favourable outcome and recovery.

Allogenic mesenchymal stem cell-conditioned medium does not affect sperm parameters and mitigates early endometrial inflammatory responses in mares.

This study aimed to evaluate the effects of mesenchymal stem cell-conditioned medium (MSC-CM) on sperm parameters, intrauterine polymorphonuclear neutrophils (PMN), intrauterine fluid accumulation (IUF), and fertility in mares. In experiment 1, two ejaculates from ten stallions were extended to 50 million sperm/mL using a milk-based extender. Thereafter, 20 mL of extended semen was added of MSC-CM as follows: 0, 5, 10, 15, and 20 mL. Sperm kinetics and plasma membrane integrity were evaluated immediately after dilution (T0) and 2 h post-incubation at 37 °C (T2). In experiment 2, mares characterized as resistant (n = 13) or susceptible (n = 7) to endometritis were inseminated with fresh semen 24 h post-induction of ovulation in two (Control and CM-1) and three (Control, CM-1, and CM-2) cycles in a crossover, as follows: control, no pharmacological interference; CM-1, supplementation of semen insemination dose at 3:4 (v:v, MSC-CM:semen); CM-2, 30 mL of MSC-CM was infused into the uterus 24 h before insemination. Endometrial cytology and uterine fluid were collected 6 and 24 h after insemination to evaluate the number of PMNs and concentrations of interleukins IL6, IL10, and TNFα. IUF was determined by ultrasonography 24 and 48 h after insemination. Pregnancy status was diagnosed 14 days after ovulation. The addition of MSC-CM to semen did not influence sperm parameters at T0 and T2 (P > 0.05) and reduced (CM-1; P < 0.05) the number of PMNs at 6 h post-insemination in resistant mares. In susceptible mares, PMNs at 6 and 24 h post-insemination, as well as IUF were reduced (P < 0.05) in both treated cycles (CM-1 and CM-2). In addition, MSC-CM downregulated IL6 and upregulated IL10 concentrations in the uterus of susceptible mares after insemination. There were no differences in fertility rates among groups both in resistant (Control, 77%, 10/13; CM-1, 62%, 8/13) and susceptible mares (Control, 42.8%, 3/7; CM-1, 57.1%, 4/7; CM-2, 85.7%. 6/7). In conclusion, MSC-CM did not affect sperm parameters when mixed with diluted semen, and reduced post-insemination inflammatory responses in mares.

Characterization of semen collected by pharmacologically induced ejaculation from a stallion with seminal vesiculitis.

The present study compared the quality of sperm collected by artificial vagina or pharmacologically induced ejaculation from a 10-year-old thoroughbred stallion with seminal vesiculitis. The pharmacological protocol involved intravenous administration of detomidine (0.01 mg/kg) and oxytocin (20 IU) and successfully induced ejaculation in all attempts of semen collection. Sperm motility, plasma membrane and acrosome integrity (PMAI), reactive oxygen species (ROS) levels, polymorphonuclear neutrophil (PMN) percentage, and bacterial profiles of fresh and cooled semen (5°C for 24 hr) were evaluated. Semen obtained by the pharmacological method presented reduced seminal volume, decreased PMN percentage and superior sperm motility in cooled samples. Moreover, higher PMAI and lower ROS levels were observed in semen collected by the pharmacological method. Therefore, pharmacologically induced ejaculation is an alternative to obtain semen with minimal contamination and with sperm of superior quality and longevity from stallions with seminal vesiculitis.

Effects of the cryopreservation process on dog sperm integrity.

Sperm cryopreservation has become an indispensable tool in reproductive biology. However, frozen/thawed semen has a short lifespan due to loss of sperm cell integrity. To better understand which sperm cell structures are compromised by the cryopreservation process and apoptosis markers, the sperm of five healthy mature dogs was analyzed in this study. Analysis was performed after collection, cooling, and thawing via computer assisted sperm analyzer (CASA) and evaluation of membrane fluidity and permeability, phosphatidylserine translocation (Annexin V), membrane integrity, mitochondrial membrane potential, membrane lipid peroxidation (LPO) and activity of the apoptotic markers caspases 3 and 7 by flow cytometry. Cryopreservation decreased total and progressive motility and the percentage of rapid sperm (P < 0.01). Damage to sperm cells was confirmed by Annexin V (P < 0.01), indicating that capacitation-like changes were induced by the cryopreservation procedures. An increase in sperm membrane fluidity was also noted in frozen/thawed samples (P < 0.01). Plasma and acrosomal cell membranes were affected (P < 0.01), with decreases in the subpopulation displaying high membrane potential (P < 0.01). Membrane LPO was increased in thawed sperm compared to cooled sperm (P < 0.05) but was not different from that in fresh sperm. No differences were observed in caspase 3 and 7 activity after cooling, freezing, or thawing. In conclusion, total and progressive motility, plasma membrane integrity and mitochondrial membrane potential suffered from the deleterious effects caused by cryopreservation, unlike the activity of caspases that remained stable during the freezing process.

Proteomic data of seminal plasma and spermatozoa of four purebred dogs.

Semen contains several proteins that are important to fertilization and to identify reproductive failures. There are proteins that are specie-specific expressed, although differs among several breeds. This article provides experimental data describing the protein profile of seminal plasma and spermatozoa of four healthy purebred dogs: Golden Retriever (n=3), Bernese Mountain Dog (n=4), Great Dane (n=3), and Maremmano-Abruzzese Sheepdog (n=3), housed at São Paulo state, Brazil. Semen samples were collected by manual stimulation of the penis in a presence of a teaser bitch, when possible. The seminal plasma and sperm cells were separated by centrifugation and prepared for mass spectrometry. The gene ontology annotation of the proteins found is described. This is the first time that proteomic profile of the semen of purebred dogs is described. These data are a valuable resource to improve the biotechnologies of reproduction applied to canid species.

Clinical safety of intratesticular transplantation of allogeneic bone marrow multipotent stromal cells in stallions.

Although stem cell therapy is a promising alternative for treatment of degenerative diseases, there are just few reports on the use of stem cells therapy in horse's reproductive system. This study aims to evaluate the effect of intratesticular injection of bone marrow mesenchymal stromal/stem cells (MSCs) in healthy stallions, and its outcome on seminal parameters and fertility. In Experiment 1, 24 stallions were divided into treatment group (TG) and control group (CG). In the TG, an intratesticular application of MSC was performed, and in the CG, only PBS was used. Measurements of testicular volume, surface temperature and Doppler ultrasonography were performed 24 and 48 hr after treatments. Fifteen days after application, the testicles were removed and submitted to histological analysis. In Experiment 2, 3 fertile stallions received similarly treatment with MSCs. Physical examination and sperm analysis were performed weekly during 60 days after treatment, and at the end, semen from one of them was used for artificial inseminations of 6 healthy mares. In Experiment 1, clinical examinations showed no signals of acute inflammation on both groups according to the analysed variables (p > .05). Also, no signal of chronic inflammation was observed on histological evaluation. In Experiment 2, stallions presented no physical alterations or changes in sperm parameters, and a satisfactory fertility rate (83%; 5/6) was observed after AI. The results support the hypothesis that intratesticular application of bone marrow MSCs is a safe procedure, and this could be a promising alternative to treat testicular degenerative conditions.

Effect of Using Two Cryopreservation Methods on Viability and Fertility of Frozen Stallion Sperm.

Studies involving different methods and techniques of cryopreservation and its interactions with the conception rates in artificial insemination (AI) programs are reported in the literature. This study evaluated the sperm kinetics, plasma membrane integrity, and fertility rates of mares inseminated with cryopreserved stallion semen subjected to different freezing methods. For this, four ejaculates from five stallions were collected and frozen in conventional (Styrofoam box) or automated system in Mini-Digitcool ZH 400. Seminal samples were evaluated after thawing for sperm motion parameters by CASA and plasma membrane integrity by epifluorescence microscopy. For the fertility trial, a cross-over model was performed using 100 cycles of 50 mares, which were inseminated by one the two freezing methods. No differences were observed for sperm motion parameters and plasma membrane integrity between groups (P > .05). The pregnancy rate using the conventional method was 56% (28/50) and did not differ (P = .5406) from the pregnancy rate (64%, 32/50) obtained using the automatized method. The use of semen from fertile stallions may not illustrate small differences in the two freezing methods evaluated. Conventional and automated freezing systems did not differ in the quality and viability of fertile stallion semen and conception rates, indicating that the two methodologies can be safely used in AI programs.

Can centrifugation force compromise the plasmatic membrane, acrosome and DNA integrity of goat spermatozoa? / A força de centrifugação pode comprometer a integridade de membrana plasmática, acrossomal e DNA de espermatozoides caprinos?

Protocols for cooling or freezing goat semen usually recommend centrifugation for seminal plasma removal. However, little is known about the effect of this process on goat sperm viability and functionality. The present study evaluated the effects of centrifugation force on the plasma membrane, acrosomes, and DNA integrity of goat semen. Four ejaculates from each of the four different Anglo Nubian male goats were used. Semen samples were obtained using artificial vagina, and immediately after collection, ejaculates were diluted using Ringer's sodium lactate solution and split into three groups: Control (CG, without centrifugation), G1 (centrifugation 600 x g/10 min), G2 (centrifugation 1200 x g/10 min). After centrifugation, seminal plasma was removed, the sperm pellets were resuspended using Tris-egg yolk extender (80 x 106 spermatozoa/mL) and the sperm morphology was analyzed. Samples were cooled at 5°C for 5, 24, 36, and 48 h and then sperm plasma membrane and acrosome integrity (PMAI, %) and sperm DNA fragmentation index (SDF, %) were evaluated at each time-point, using a flow cytometer. Additionally, sperm movement was determined using computer semen analysis (CASA) after 5, 24, and 48 h of refrigeration period. The semen centrifugation did not induce additional sperm morphology defect or reduction in sperm kinetics in the experimental groups. Differences were not observed (p > 0.05) in PMAI and SDF among different groups, in any of each time-point of the cooling process. In conclusion, centrifugation, even at high speeds, did not affect goat sperm integrity and functionality when submitted to refrigeration process. (AU)

A maior parte dos protocolos de refrigeração e criopreservação do sêmen caprino recomenda o uso de centrifugação para remoção do plasma seminal. No entanto, não existe consenso sobre o risco que esse tipo de processamento pode ocasionar à viabilidade espermática. Nesse contexto, o presente trabalho investigou os possíveis efeitos deletérios da centrifugação sobre a integridade estrutural e DNA de espermatozoides caprinos. Para a pesquisa foram selecionados quatro reprodutores para colheita de sêmen (n = 4 ejaculados/bode). Cada ejaculado foi fracionado em três alíquotas iguais, diluídas em ringer e divididas em três grupos: Controle (GC, não centrifugado), G1 (centrifugação a 600 g/10 minutos) e G2 (centrifugação a 1200 g/10 minutos). As amostras seminais por grupo foram diluídas em meio Tris gema respeitando-se a concentração final de 80 milhões de espermatozoides/mL e foram submetidas à avaliação de morfologia espermática. Todas as amostras foram acondicionadas a 5°C, sendo analisadas nos momentos 5, 24, 36 e 48 horas do processo de refrigeração por meio da avaliação da integridade de membrana plasmática e acrossomal (MPAI, %) e índice de fragmentação de DNA (IDF, %). Adicionalmente, a cinética espermática foi avaliada com o emprego de um sistema computadorizado de análise (CASA) nos momentos 5, 24 e 48 horas da refrigeração. A centrifugação não induziu a manifestação de defeitos morfológicos ou redução significativa da cinética de espermatozoides caprinos. Não foram observadas diferenças para a integridade de membrana plasmática e para o índice de fragmentação de DNA quando comparados, respectivamente, GC, G1 e G2 em cada um dos quatro momentos experimentais. Conclui-se que mesmo quando empregadas altas forças de rotação não ocorre lesão à ultraestrutura dos espermatozoides caprinos submetidos ao processo de refrigeração.(AU)

Evaluation of cooling and freezing systems of bovine semen.

Semen cryopreservation comprises different steps, among them are the cooling and freezing rates which significantly influence the quality of thawed sperm. Different systems with variable freezing rates are used for freezing bull semen in the field, with a consequence of variable success rates. The objective of this study was to compare different systems for freezing bull semen in the field. Five cooling methods of semen and two methods for the subsequent freezing phase (5 × 2 factorial scheme) were used. Two to four ejaculates were collected from 12 bulls with an electroejaculator. The ejaculates were diluted in BotuBov® to a concentration of 50 × 106 spermatozoa/mL in 0.5-mL straws. After dilution, the straws were cooled to 5 °C in five cooling systems: TK 4000® at a cooling rate of -0.25 °C/min (R1); TK 4000® at a rate of -0.5 °C/min (R2); Minitube® refrigerator at a rate of -2.8 °C/min (R3); Botutainer® at a rate of -0.65 °C (R4), and domestic refrigerator at a rate of -2.0 °C/min (R5). After stabilization at 5 °C for 4 h, these straws were then submitted to two freezing systems: TK 4000® at a freezing rate of -15 °C/min (C1) and Styrofoam box with liquid nitrogen at a rate of -19 °C/min (C2). Sperm kinetics were evaluated by computer-assisted sperm analysis at four time points: in fresh semen, after cooling, post-thawing, and after the rapid thermal resistance test (TRT). In addition, plasma and acrosomal membrane integrity, mitochondrial potential and intracellular H2O2 were analyzed after thawing by flow cytometry. The R1, R2 and R4 cooling systems were the most efficient in preserving sperm viability, membrane integrity and intracellular H2O2. Samples frozen in the C1 system exhibited better post-thaw and post-TRT kinetics than C2 samples. In conclusion, slower cooling curves in conjunction with a constant freezing rate obtained with the programmable unit were more efficient for freezing bull semen in the field.

Effect of seminal plasma removal before cryopreservation of bovine semen obtained by electroejaculation on semen quality and in vitro fertility.

Cryopreservation of bull semen is a common biotechnology procedure in cattle breeding. However, when the ejaculate is obtained by electroejaculation, wide variation is observed in the sperm/seminal plasma (SP) ratio that can affect the freezability of semen in this species. The removal of SP may improve the quality of frozen bull semen. The objective of this study was to evaluate the effect of SP removal from the ejaculate on the cryopreservation of semen from 38 Nellore bulls collected by electroejaculation. After collection, the ejaculate was divided into three aliquots: (1) control (N) diluted to a concentration of 60 × 106 spermatozoa/mL and frozen with SP; (2) centrifugation (C) at ×600g for 10 minutes and the pellet resuspended and frozen at the same concentration as N; and (3) filtration (F) through SpermFilter and sperm recovered and frozen at the same concentration as N. After thawing, sperm kinetics, plasma and acrosome membrane integrity, mitochondrial membrane potential, oxidative stress, and in vitro fertility were evaluated. Statistical analysis was performed using the SAS 9.2 package, and differences were considered significant when P < 0.05. Higher average path velocity and straight-line velocity were observed in the groups submitted to SP removal compared to the control group (P < 0.01). In contrast, filtered samples exhibited higher beat cross frequency, straightness, and linearity compared to the other groups. Plasma membrane integrity was reduced when SP was removed, but lower oxidative stress was observed in groups C and F (34.91 ± 2.95% and 31.63 ± 2.95%, respectively) compared to group N (57.39 ± 2.95%). However, the percentage of hatched blastocysts was similar in the N and F groups (21.22 ± 1.05% and 24.00 ± 1.05%, respectively) and higher compared to group C (18.83 ± 1.05%). In conclusion, removal of SP by centrifugation for bull semen freezing reduced the rate of in vitro-produced embryos, whereas filtration of prefrozen semen was found to be an efficient alternative in terms of semen freezability and in vitro production of bovine embryos.

Sensitivity evaluation of the computer-assisted sperm analysis (CASA) in the determination of frozen-thawed bull semen concentration / Avaliação da sensibilidade da técnica computadorizada de análise (CASA) para a determinação da concentração espermática do sêmen bovino congelado

Sperm concentration is traditionally evaluated by counting cells in a hemocytometric Neubauer chamber, often a highly subjective, time-consuming, and laborious technique prevalent in andrology laboratories around the world. However, the Computer-Assisted Semen Analysis (CASA) represents a more consistent method of evaluating sperm concentration that may provide enhancing efficiencies of sperm count. The purpose of this study is to compare the results of these two methods in the analysis of post-thaw concentration of bovine semen. Four hundred and twenty five batches of semen from different bulls were selected, thawed at 37°C for 30 seconds and then homogenized. Aliquots of 40 µL of semen were diluted in 960 µL of distilled water, fixing the rate at 1:25 dilution for analysis in a Neubauer chamber. Conversely, aliquots of 5 µL for each semen dose were submitted to CASA, considered a minimum of five random fields and 2000 sperm count per analysis. The average concentration of sperm cells was 38.96a ± 1.28 in the Neubauer analysis and 35.14b ± 0.82 for the CASA, with the correlation coefficient of 0.87 (P < 0.0001) and reliability of 0.78 (scale ranging from 0 to 1) between the two methods. In conclusion, the results of two techniques for assessing sperm concentration have similar results. However the CASA methodology would yield greater benefit due to precision, consistency, and reduced disposal issues, particularly for large processing laboratories.(AU)

Tradicionalmente, a concentração espermática é avaliada por meio da contagem de células em câmara hemocitométrica de Neubauer, técnica laboriosa adotada na rotina dos laboratórios de andrologia. Uma alternativa para essa contagem é a técnica computadorizada de avaliação espermática (CASA), método que pode aumentar a eficiência e acurácia na determinação da concentração de espermatozoides em uma amostra de sêmen. O presente trabalho relata a avaliação da sensibilidade da técnica CASA para o acesso da concentração de espermatozoides bovinos em pósdescongelação. Foram selecionadas 425 doses de sêmen de reprodutores de diferentes raças, descongeladas a 37°C por 30 segundos e homogeneizadas. Alíquotas de 40 µL de sêmen foram transferidas para tubos cônicos de 1,5 mL previamente preenchidos com 960 µL de água destilada, fixando a taxa de diluição em 1:25 para contagem em câmara de Neubauer. Em contrapartida, alíquotas de 5 µL de cada dose de sêmen foram avaliadas com o emprego do sistema CASA considerando o número mínimo de cinco campos aleatórios e 2 mil espermatozoides por análise. A concentração média de células espermáticas foi de 38,96a ± 1,28 e 35,14b ± 0,82,respectivamente para amostras avaliadas em câmara de Neubauer ou sistema computadorizado, apresentando o coeficiente de correlação de 0,87 (P < 0.0001) e concordância de 0,78 (escala de 0 a 1). Conclui-se que as duas técnicas de avaliação da concentração espermática possuem eficiência similar. No entanto, em virtude da precisão, rapidez e por dispensar a diluição prévia das amostras para a contagem, a CASA é uma alternativa para a contagem de células espermáticas em câmara de Neubauer, sobretudo para grandes centrais de produção de sêmen bovino congelado.(AU)

Advances in Stallion Semen Cryopreservation.

The use of stallion frozen semen minimizes the spread of disease, eliminates geographic barriers, and preserves the genetic material of the animal for an unlimited time. Significant progress on the frozen thawed stallion semen process and consequently fertility has been achieved over the last decade. These improvements not only increased fertility rates but also allowed cryopreservation of semen from "poor freezers." This article reviews traditional steps and new strategies for stallion semen handling and processing that are performed to overcome the deleterious effects of semen preservation and consequently improve frozen semen quality and fertility.

Strategies to improve the fertility of fresh and frozen donkey semen.

Fertility rates of donkey semen in jennies are lower compared to mares. The aims of this study were to evaluate different sperm cryopreservation methods and insemination strategies to improve the fertility of donkey semen in jennies. Three experiments were performed: (1) the comparison of two freezing methods of donkey semen (conventional method and automated method); (2) the determination of a suitable insemination dose of fresh donkey semen for jennies and mares; and (3) the influence of the semen deposition site on fertility of jennies inseminated with frozen donkey semen. For experiment 1, no differences were observed in total motility, angular velocity, curvilinear velocity, straight-line velocity, and plasma membrane integrity between samples frozen with the conventional (Styrofoam box) and the automated method (TK 4000C). However, the automated method provided higher values of progressive motility and rapid cells in frozen-thawed samples in comparison with the conventional method (P < 0.05). For experiment 2, mares were bred using 500 × 10(6) fresh sperm (M); and jennies using 1 × 10(9) (J1) or 500 × 10(6) fresh sperm (J5). Pregnancy rates in M, J1, and J5 were 93% (14/15), 73% (11/15), and 40% (6/15), respectively. When using different insemination doses, 500 × 10(6) or 1 × 10(9) sperm, no significant difference was observed in pregnancy rates of mares (M, 14/15) and jennies (J1, 11/15). Furthermore, there was no significant difference between the two insemination doses in jennies. However, with an insemination dose of 500 × 10(6) fresh sperm, the pregnancy rates were significantly higher in mares (M, 14/15) than in jennies (J5, 6/15; P < 0.05). For experiment 3, the inseminations were carried out in the uterine body (UB) or in the uterine horn of jennies with frozen-thawed donkey semen. No pregnancies were achieved with inseminations performed in the UB (0/12). The pregnancy rate for uterine horn group was 28.26% (13/46) and thus significantly higher than the UB group (0%; 0/12; P < 0.05). In conclusion, the automated method showed higher values on progressive motility and rapid cells parameters compared to the conventional method and can be used as an alternative for freezing donkey semen. The increase in the number of sperm cells per insemination dose using fresh donkey semen improved the fertility rates in jennies. The deep horn inseminations using frozen-thawed donkey semen increased the pregnancy rate in jennies, and the multiple inseminations may be an option to improve the fertility rates of donkey semen in jennies.