Zinc sulphate turbidity as a screening test of passive transfer of immunity in newborn foals

Background: Passive immunity acquired by colostrum ingestion is essential to prevent neonatal infections. Failure ofpassive transfer (FPT) of maternal immunity occurs in foals that fail to absorb enough immunoglobulins within 24 h afterbirth. Foals with FPT are at increased risk of infections and death. Serum samples from neonatal foals might be examinedfor FPT using the zinc sulphate turbidity (ZST) test. The aim of this study was to investigate the accuracy of the ZST test,performed at two different times after first suckling (12 and 18 h), to detect FPT in newborn foals. The effect of temperatureon the turbidity intensity resulting from the ZST reaction was also investigated.Materials, Methods & Results: Blood samples were collected from 112 newborn foals at 12 h after the first colostrumintake. In 36 foals, additional serum samples were collected at 18 h after first colostrum intake. The serum samples weretested with the ZST test and, later, in the laboratory setting, the ZST test was repeated. The IgG levels were measured bysingle radial immunodiffusion (SRID), which was used as the reference method. The standard solution used for the interpretation of results had a turbidity corresponding to approximately 800 mg/dL of immunoglobulins (IgG). The mean IgG concentration measured at 12 and 18 h after the first colostrum intake was analyzed using the t-test for paired samples.Values of absorbance of ZST test under different temperatures were analyzed using a one-way analysis of variance, andmeans were compared using the Tukey test. The relationship between the temperature of the solution and absorbance wasdetermined using the Pearsons correlation coefficient. Based on SRID results, 12 foals (10.7%) had serum IgG concentration < 400 mg and 26 foals (23.2%) had IgG levels between 400 and 800 mg/dL. Serum levels of IgG determined bySRID in 36 foals were similar (P > 0.05) between 12 h (943.9 ± 508.6 mg/dL) and 18 h (975.9 ± 525.6 mg/dL)...(AU)

Zinc sulphate turbidity as a screening test of passive transfer of immunity in newborn foals

Background: Passive immunity acquired by colostrum ingestion is essential to prevent neonatal infections. Failure ofpassive transfer (FPT) of maternal immunity occurs in foals that fail to absorb enough immunoglobulins within 24 h afterbirth. Foals with FPT are at increased risk of infections and death. Serum samples from neonatal foals might be examinedfor FPT using the zinc sulphate turbidity (ZST) test. The aim of this study was to investigate the accuracy of the ZST test,performed at two different times after first suckling (12 and 18 h), to detect FPT in newborn foals. The effect of temperatureon the turbidity intensity resulting from the ZST reaction was also investigated.Materials, Methods & Results: Blood samples were collected from 112 newborn foals at 12 h after the first colostrumintake. In 36 foals, additional serum samples were collected at 18 h after first colostrum intake. The serum samples weretested with the ZST test and, later, in the laboratory setting, the ZST test was repeated. The IgG levels were measured bysingle radial immunodiffusion (SRID), which was used as the reference method. The standard solution used for the interpretation of results had a turbidity corresponding to approximately 800 mg/dL of immunoglobulins (IgG). The mean IgG concentration measured at 12 and 18 h after the first colostrum intake was analyzed using the t-test for paired samples.Values of absorbance of ZST test under different temperatures were analyzed using a one-way analysis of variance, andmeans were compared using the Tukey test. The relationship between the temperature of the solution and absorbance wasdetermined using the Pearson’s correlation coefficient. Based on SRID results, 12 foals (10.7%) had serum IgG concentration 0.05) between 12 h (943.9 ± 508.6 mg/dL) and 18 h (975.9 ± 525.6 mg/dL)...

Sodium bicarbonate and HEPES as buffer components for cooling the semen of pony stallions / Bicarbonato de sódio e HEPES como tampões para o resfrigeração de sêmen de pôneis

The composition of semen diluents can modify its viability during cooling. The buffering effects of HEPES and sodium bicarbonate were evaluated considering the pH and sperm viability. The semen of seven adult Brazilian ponies was evaluated before and after cooling at 5o C for 24 h and 48 h. A non-buffered skim milk powder extender (C) and the same extender buffered with sodium bicarbonate (SB) and HEPES (H) were used. After dilution, semen (three ejaculates/pony) was centrifuged and the seminal plasma discarded. Sperm was then diluted with SB, H or C and its concentration adjusted to 50 x 106 sptz/mL. Progressive motility evaluated after dilution showed similar results with all extenders (71.42% (SB), 74.28% (H), and 74.52% (C)). Sperm motility was evaluated 24 h and 48 h after cooling for SB (44.76% and 25.23%), H (51.42% and 38.09%) and C (54.05% and 41.66%, respectively). Plasma membrane integrity was similar after exposure to the three extenders (62.71% (SB), 68.76% (H), and 69.23% (C)). Mitochondrial activity was higher in SB immediately after dilution (SB= 1.05nm, H= 0.81nm, C= 0.79nm), and after 24 h (0.83nm (SB), 0.73nm (H) and 0.64nm (C)). After 48 h, the mitochondrial activity decreased to 0.72nm (SB), 0.69nm (H), and 0.63nm (C) (P > 0.05). The pH, osmolarity and pH after 48 h of cooling of the diluted semen were higher in SB (8; 382; 7.9), intermediate in H (7.5; 362; 7.32) and lower in C (7.16; 350; 7.07). Lipid peroxidation and its induction were similar in all groups. Data were analyzed by analysis of variance (ANOVA), and Duncan’s test was used to evaluate the significant differences (P < 0.05). Sodium bicarbonate reduced the progressive motility and increased the semen pH. The extender C was considered more appropriate for immediate use in artificial insemination. The non-buffered and HEPES-buffered extenders were considered appropriate for the cooling of equine semen for 48 h at 5°C.

A composição dos diluentes de sêmen pode modificar sua viabilidade durante o processo de resfriamento. O efeito de tamponamento do HEPES e Bicarbonato de Sódio foi avaliado considerando o pH e a viabilidade espermática. Sete pôneis brasileiros adultos tiveram seu sêmen avaliado antes e após a refrigeração a 5°C durante 24 h e 48 h. Um diluente de leite em pó desnatado não tamponado (C) e um diluente tamponado com bicarbonato de sódio (SB) ou HEPES (H) foram utilizados. Após a diluição, o sêmen (três ejaculados/ pônei) foi centrifugado e o sobrenadante foi descartado. O sêmen foi então diluído com SB, H ou C e a concentração ajustada para 50 x 106 espermatozoides/mL. A motilidade progressiva avaliada após a diluição apresentou resultados similares para todos os diluentes (71,42% (SB), 74,28% (H), 74,52% (C)). A motilidade espermática foi avaliada 24 h e 48 h após o resfriamento, respectivamente, para SB (44,76%, 25,23%), H (51,42%, 38,09%) e C (54,05%, 41,66%). A integridade da membrana plasmática foi semelhante após a exposição aos três diluentes (62,71% (SB), 68,76% (H), 69,23% (C)). A atividade mitocondrial após a diluição foi maior em SB (SB = 1.05nm, H = 0.81nm, C = 0.79nm) e após 24 h foi 0.83nm (SB), 0.73nm (H) e 0.64nm (C). A atividade mitocondrial após 48 h diminuiu para 0.72nm (SB), 0.69nm (H) e 0.63nm (C) (P > 0.05). O pH, a osmolaridade e o pH do sêmen diluído após as 48 h de refrigeração foram maiores em SB (8; 382; 7,9), intermediário em H (7,5; 362; 7,32) e menor em C (7,16; 350; 7,07). A peroxidação lipídica e sua indução foram semelhantes em todos os grupos. As médias foram avaliadas através de análise de variância (ANOVA) e o Teste Duncan foi utilizado para analisar as diferenças significativas (P < 0.05). O bicarbonato de sódio reduziu a motilidade progressiva e aumentou o pH do sêmen. O diluente C foi considerado mais adequado para uso imediato na inseminação artificial...

Sodium bicarbonate and HEPES as buffer components for cooling the semen of pony stallions / Bicarbonato de sódio e HEPES como tampões para o resfrigeração de sêmen de pôneis

The composition of semen diluents can modify its viability during cooling. The buffering effects of HEPES and sodium bicarbonate were evaluated considering the pH and sperm viability. The semen of seven adult Brazilian ponies was evaluated before and after cooling at 5o C for 24 h and 48 h. A non-buffered skim milk powder extender (C) and the same extender buffered with sodium bicarbonate (SB) and HEPES (H) were used. After dilution, semen (three ejaculates/pony) was centrifuged and the seminal plasma discarded. Sperm was then diluted with SB, H or C and its concentration adjusted to 50 x 106 sptz/mL. Progressive motility evaluated after dilution showed similar results with all extenders (71.42% (SB), 74.28% (H), and 74.52% (C)). Sperm motility was evaluated 24 h and 48 h after cooling for SB (44.76% and 25.23%), H (51.42% and 38.09%) and C (54.05% and 41.66%, respectively). Plasma membrane integrity was similar after exposure to the three extenders (62.71% (SB), 68.76% (H), and 69.23% (C)). Mitochondrial activity was higher in SB immediately after dilution (SB= 1.05nm, H= 0.81nm, C= 0.79nm), and after 24 h (0.83nm (SB), 0.73nm (H) and 0.64nm (C)). After 48 h, the mitochondrial activity decreased to 0.72nm (SB), 0.69nm (H), and 0.63nm (C) (P > 0.05). The pH, osmolarity and pH after 48 h of cooling of the diluted semen were higher in SB (8; 382; 7.9), intermediate in H (7.5; 362; 7.32) and lower in C (7.16; 350; 7.07). Lipid peroxidation and its induction were similar in all groups. Data were analyzed by analysis of variance (ANOVA), and Duncans test was used to evaluate the significant differences (P < 0.05). Sodium bicarbonate reduced the progressive motility and increased the semen pH. The extender C was considered more appropriate for immediate use in artificial insemination. The non-buffered and HEPES-buffered extenders were considered appropriate for the cooling of equine semen for 48 h at 5°C.(AU)

A composição dos diluentes de sêmen pode modificar sua viabilidade durante o processo de resfriamento. O efeito de tamponamento do HEPES e Bicarbonato de Sódio foi avaliado considerando o pH e a viabilidade espermática. Sete pôneis brasileiros adultos tiveram seu sêmen avaliado antes e após a refrigeração a 5°C durante 24 h e 48 h. Um diluente de leite em pó desnatado não tamponado (C) e um diluente tamponado com bicarbonato de sódio (SB) ou HEPES (H) foram utilizados. Após a diluição, o sêmen (três ejaculados/ pônei) foi centrifugado e o sobrenadante foi descartado. O sêmen foi então diluído com SB, H ou C e a concentração ajustada para 50 x 106 espermatozoides/mL. A motilidade progressiva avaliada após a diluição apresentou resultados similares para todos os diluentes (71,42% (SB), 74,28% (H), 74,52% (C)). A motilidade espermática foi avaliada 24 h e 48 h após o resfriamento, respectivamente, para SB (44,76%, 25,23%), H (51,42%, 38,09%) e C (54,05%, 41,66%). A integridade da membrana plasmática foi semelhante após a exposição aos três diluentes (62,71% (SB), 68,76% (H), 69,23% (C)). A atividade mitocondrial após a diluição foi maior em SB (SB = 1.05nm, H = 0.81nm, C = 0.79nm) e após 24 h foi 0.83nm (SB), 0.73nm (H) e 0.64nm (C). A atividade mitocondrial após 48 h diminuiu para 0.72nm (SB), 0.69nm (H) e 0.63nm (C) (P > 0.05). O pH, a osmolaridade e o pH do sêmen diluído após as 48 h de refrigeração foram maiores em SB (8; 382; 7,9), intermediário em H (7,5; 362; 7,32) e menor em C (7,16; 350; 7,07). A peroxidação lipídica e sua indução foram semelhantes em todos os grupos. As médias foram avaliadas através de análise de variância (ANOVA) e o Teste Duncan foi utilizado para analisar as diferenças significativas (P < 0.05). O bicarbonato de sódio reduziu a motilidade progressiva e aumentou o pH do sêmen. O diluente C foi considerado mais adequado para uso imediato na inseminação artificial...(AU)

Viability of pony stallion semen in different temperature and dilution

Background: Artificial insemination and transport of cooled semen has been routinely used in equine industry in the past 20 years. However, more investigations are needed regarding the methods for long time storage in pony stallion semen. The effect of dilution and cooling temperature on pH, sperm motility, membrane integrity and mitochondrial activity were investigated before and after cooling of stallion semen.Materials, Methods & Results: Two ejaculates each from nine Brazilian ponies were diluted in a nonbuffered powder milk extender cooled at 5°C or 15°C for 48 h using three different dilutions (1:1, 1:2 or 1:3). Data were assessed by analysis of variance and the rate comparison was performed using the Duncan test. Samples diluted 1:1 at 5o C or 15°C showed higher pH values (7.63 ± 0.34 e 7.57 ± 0.27) and lower progressive motility (10.3 ± 11.05, 17.08 ± 9.95). All samples cooled at 15°C also showed lower incidence of morphologically altered spermatozoa (1:1 = 55.84%; 1:2 = 51.84%; 1:3 = 49.95%) [P 0.05) despite time and temperature. The pH, progressive motility, mitochondrial activity and membrane integrity remained similar (P > 0.05) on fresh semen samples independent of the dilution grade used. The best results were obtained when semen was diluted 1:3 and cooled at 15°C. All dilution grades were safe for fresh semen and pH wasincreased when semen was diluted and cooled for 48 h.[...]

Viability of pony stallion semen in different temperature and dilution

Background: Artificial insemination and transport of cooled semen has been routinely used in equine industry in the past 20 years. However, more investigations are needed regarding the methods for long time storage in pony stallion semen. The effect of dilution and cooling temperature on pH, sperm motility, membrane integrity and mitochondrial activity were investigated before and after cooling of stallion semen.Materials, Methods & Results: Two ejaculates each from nine Brazilian ponies were diluted in a nonbuffered powder milk extender cooled at 5°C or 15°C for 48 h using three different dilutions (1:1, 1:2 or 1:3). Data were assessed by analysis of variance and the rate comparison was performed using the Duncan test. Samples diluted 1:1 at 5o C or 15°C showed higher pH values (7.63 ± 0.34 e 7.57 ± 0.27) and lower progressive motility (10.3 ± 11.05, 17.08 ± 9.95). All samples cooled at 15°C also showed lower incidence of morphologically altered spermatozoa (1:1 = 55.84%; 1:2 = 51.84%; 1:3 = 49.95%) [P < 0.01]. Mitochondrial activity was higher on the 1:3 dilution (0.86 ± 0.19 nm) at 5°C and on the 1:1 (0.89 ± 0.23 nm), 1:2 (0.93 ± 0.2 nm) and 1:3 (0.92 ± 0.2 nm) dilutions at 15°C. Progressive motility was higher when semen was diluted 1:3 and cooled at 15°C (42.22 ± 12.38; P < 0.05). Considering mitochondrial activity, similar results were observed when different dilutions of semen were used (P > 0.05) despite time and temperature. The pH, progressive motility, mitochondrial activity and membrane integrity remained similar (P > 0.05) on fresh semen samples independent of the dilution grade used. The best results were obtained when semen was diluted 1:3 and cooled at 15°C. All dilution grades were safe for fresh semen and pH wasincreased when semen was diluted and cooled for 48 h.[...](AU)

Cryopreservation protocol for equine platelet-rich plasma / Protocolo de criopreservação para plasma rico em plaquetas de equinos

In this preliminary study, a new equine platelet-rich plasma (PRP) cryopreservation protocol was evaluated. PRP was obtained by a double centrifugation technique of whole blood collected from 8 adult healthy ponies. A fresh sample of PRP was analyzed for total platelet count, mean platelet volume (MPV), and platelet morphology. Upon morphological evaluation, 200 platelets were counted using a differential interference contrast microscope with a 40x phase objective and classified as activated (with pseudopodia), inactivated (normal discoid shape), or uncertain state (spherical shape, without pseudopodia). Two other PRP samples, one containing DMSO as a cryoprotectant and the other without DMSO, were stored in a mechanical freezer at 80ºC. After 14 days, the frozen samples were thawed and submitted to the same analysis as described above. The fresh PRP showed a platelet count of 830 (±95.3) x103 uL-1, an MPV of 5.2 (±0.07) fL, and composed of 4% activated platelets. There was no significant difference in platelet count, MPV, and activated platelets between fresh and 6% DMSO frozen PRP samples (617.9±65.5x103uL-1; 5.3±0.06fL; 9.5%) (p > 0.05). On the other hand, samples frozen without DMSO showed a significantly lower platelet count (519.6±66.1x103uL-1), higher MPV (5.7±0.08fL), and more activated platelets (13.9%) than the other groups (p 0.05). The 6% DMSO was able to...(AU)

Neste estudo preliminar, um novo protocolo de criopreservação de plasma rico em plaquetas (PRP) de equinos foi avaliado. O PRP foi obtido através de dupla centrifugação do sangue total coletado de oito pôneis clinicamente saudáveis. Uma amostra de PRP fresco foi analisada quanto ao número total de plaquetas, volume plaquetário médio (VPM) e morfologia plaquetária. Na avaliação morfológica 200 plaquetas foram contadas utilizando um microscópio com contraste de fase com objetiva de 40x e classificadas como ativadas (com pseudópodes), inativas (forma discóide normal) ou estado incerto (forma esférica, mas sem peseudópodes). Duas outras amostras de PRP foram armazenadas em um freezer mecânico a 80oC, uma contendo dimetil sulfóxido (DMSO) como crioprotetor e outra sem DMSO. Após 14 dias as amostras congeladas foram descongeladas e submetidas às mesmas avaliações das amostras frescas. O PRP fresco apresentou contagem plaquetária de 830 (±95,3) x103 ?L 1, VPM 5,2 (±0,07) fL e 4% de plaquetas ativadas. Não houve diferença na contagem plaquetária, VPM e plaquetas ativadas entre as amostras de PRP frescas e congeladas com 6% de DMSO (617,9±65,5x103 uL-1; 5,3±0,06fL; 9,5%) (p > 0,05). Por outro lado, as amostras congeladas sem DMSO apresentaram uma contagem de plaquetas significativamente menor (519,6±66,1x103 u-1), maior VPM (5,7±0,08fL) e mais plaquetas ativadas (13,9%) do que os...(AU)

Cryopreservation protocol for equine platelet-rich plasma / Protocolo de criopreservação para plasma rico em plaquetas de equinos

In this preliminary study, a new equine platelet-rich plasma (PRP) cryopreservation protocol was evaluated. PRP was obtained by a double centrifugation technique of whole blood collected from 8 adult healthy ponies. A fresh sample of PRP was analyzed for total platelet count, mean platelet volume (MPV), and platelet morphology. Upon morphological evaluation, 200 platelets were counted using a differential interference contrast microscope with a 40x phase objective and classified as activated (with pseudopodia), inactivated (normal discoid shape), or uncertain state (spherical shape, without pseudopodia). Two other PRP samples, one containing DMSO as a cryoprotectant and the other without DMSO, were stored in a mechanical freezer at 80ºC. After 14 days, the frozen samples were thawed and submitted to the same analysis as described above. The fresh PRP showed a platelet count of 830 (±95.3) x103 uL-1, an MPV of 5.2 (±0.07) fL, and composed of 4% activated platelets. There was no significant difference in platelet count, MPV, and activated platelets between fresh and 6% DMSO frozen PRP samples (617.9±65.5x103uL-1; 5.3±0.06fL; 9.5%) (p > 0.05). On the other hand, samples frozen without DMSO showed a significantly lower platelet count (519.6±66.1x103uL-1), higher MPV (5.7±0.08fL), and more activated platelets (13.9%) than the other groups (p 0.05). The 6% DMSO was able to...

Neste estudo preliminar, um novo protocolo de criopreservação de plasma rico em plaquetas (PRP) de equinos foi avaliado. O PRP foi obtido através de dupla centrifugação do sangue total coletado de oito pôneis clinicamente saudáveis. Uma amostra de PRP fresco foi analisada quanto ao número total de plaquetas, volume plaquetário médio (VPM) e morfologia plaquetária. Na avaliação morfológica 200 plaquetas foram contadas utilizando um microscópio com contraste de fase com objetiva de 40x e classificadas como ativadas (com pseudópodes), inativas (forma discóide normal) ou estado incerto (forma esférica, mas sem peseudópodes). Duas outras amostras de PRP foram armazenadas em um freezer mecânico a 80oC, uma contendo dimetil sulfóxido (DMSO) como crioprotetor e outra sem DMSO. Após 14 dias as amostras congeladas foram descongeladas e submetidas às mesmas avaliações das amostras frescas. O PRP fresco apresentou contagem plaquetária de 830 (±95,3) x103 ?L 1, VPM 5,2 (±0,07) fL e 4% de plaquetas ativadas. Não houve diferença na contagem plaquetária, VPM e plaquetas ativadas entre as amostras de PRP frescas e congeladas com 6% de DMSO (617,9±65,5x103 uL-1; 5,3±0,06fL; 9,5%) (p > 0,05). Por outro lado, as amostras congeladas sem DMSO apresentaram uma contagem de plaquetas significativamente menor (519,6±66,1x103 u-1), maior VPM (5,7±0,08fL) e mais plaquetas ativadas (13,9%) do que os...

Seminal plasma: effect on motility, membrane functionality, and spermatic chromatin dispersion of equine sperm treated with N-acetyl-L-cysteine at 5C

Background: N-acetyl-L-cysteine (NAC) is a low molecular weight thiol studied as an antioxidant for stallion semen preservation without changes on sperm viability. Equine seminal plasma is rich in sulfur proteins (cysteine residues) named CRISPS, which, when combined with sulfur-containing antioxidants, can enhance the appearance of DNA lesions. The aim of this study was to assess and compare the effect of different concentrations of NAC by evaluating motility, membrane function and sperm chromatin integrity of equine semen cooled at 5C in 50% of seminal plasma. Materials, Methods & Results: Nine ejaculates from 9 stallions were divided into 4 aliquots, diluted and divided in nonsupplemented skim milk group (0.0 mM), or supplemented with 5.0, 2.5 and 0.5 mM NAC. Evaluations were made at 0 h, 24 h and 48 h of cooling, except for motility which was evaluated only up to 24 h. The 0.5 (59.7 M2) and 5.0 mM NAC (55.5 M2) groups showed similar areas of sperm chromatin dispersion among all groups. However, the area of chromatin dispersion between the non-supplemented group was higher = 65.3 M2 than the group supplemented with 2.5 mM. The percentage of cells with a functional plasma membrane was similar between supplemented and non-supplemented (0.0 mM) groups, but higher (P 0.05) in the 0.5 mM NAC (39.7 and 39.8%, respectively) than that of 2.5 mM (34.5%) and 5.0 mM [...](AU)

Seminal plasma: effect on motility, membrane functionality, and spermatic chromatin dispersion of equine sperm treated with N-acetyl-L-cysteine at 5C

Background: N-acetyl-L-cysteine (NAC) is a low molecular weight thiol studied as an antioxidant for stallion semen preservation without changes on sperm viability. Equine seminal plasma is rich in sulfur proteins (cysteine residues) named CRISPS, which, when combined with sulfur-containing antioxidants, can enhance the appearance of DNA lesions. The aim of this study was to assess and compare the effect of different concentrations of NAC by evaluating motility, membrane function and sperm chromatin integrity of equine semen cooled at 5C in 50% of seminal plasma. Materials, Methods & Results: Nine ejaculates from 9 stallions were divided into 4 aliquots, diluted and divided in nonsupplemented skim milk group (0.0 mM), or supplemented with 5.0, 2.5 and 0.5 mM NAC. Evaluations were made at 0 h, 24 h and 48 h of cooling, except for motility which was evaluated only up to 24 h. The 0.5 (59.7 M2) and 5.0 mM NAC (55.5 M2) groups showed similar areas of sperm chromatin dispersion among all groups. However, the area of chromatin dispersion between the non-supplemented group was higher = 65.3 M2 than the group supplemented with 2.5 mM. The percentage of cells with a functional plasma membrane was similar between supplemented and non-supplemented (0.0 mM) groups, but higher (P 0.05) in the 0.5 mM NAC (39.7 and 39.8%, respectively) than that of 2.5 mM (34.5%) and 5.0 mM [...]

Pregnancy rates in Criollo breed mares after ultrasound-guided follicular aspiration / Taxa de gestação em éguas da raça crioula após aspiração folicular guiada por ultrassom

There are few studies about transvaginal ultrasound-guided follicle aspiration in equine medicine regarding potential complications to future fertility of aspirated mares. In order to evaluate the effect of follicular aspiration on subsequent fertility in mares, two experiments were conducted. In Experiment I, fifteen Criollo mares were allocated to one of three groups according to the diameter of the aspirated follicle during estrus: 25-29mm (n=4; Group 1); 30-34mm (n=6; Group 2); > 35mm (n=5; Group 3) and control group (n=15; Group 4). In Experiment II, the follicular aspiration was attempted in twenty-five mares during diestrous, when at least four follicles (> 5mm) were seen in the transrectal ultrasonography of both ovaries. All visible follicles, between 4 and 8 mm, were aspirated. Thirty-one mares served as control. In Experiments I and II, the pregnancy rates in the following cycle after aspiration were 75.0% (Group 1), 83.3% (Group 2), 60.0% (Group 3), and 73.3% (Group 4 - Control); and 76.0% in the aspirated diestrous group and 77.4% in the control group (non aspirated), respectively. On both experiments, pregnancy rates were similar (P>0.05) in treated and control mares. The results of this study show that the conception rates of the first estrus period following follicular aspiration are not affected by the procedure.

Há poucos estudos sobre aspiração folicular transvaginal guiada por ultrassom na medicina equina abordando complicações futuras na fertilidade das éguas aspiradas. Com o objetivo de avaliar o efeito da aspiração folicular na fertilidade das éguas, foram conduzidos dois experimentos. No experimento I, 15 éguas da raça Crioula foram distribuídas em três grupos de acordo com o diâmetro do folículo aspirado durante o estro: 25-29mm (n=4; grupo 1); 30-34mm (n=6; grupo 2); > 35mm (n=5; grupo 3) e grupo controle (n=15; grupo 4). No experimento II, a aspiração folicular foi realizada em 25 éguas durante o diestro quando pelo menos 4 folículos (>5mm) foram observados na ultrassonografia transretal em ambos os ovários. Foram aspirados todos os folículos visíveis, entre 4 e 8 mm. Trinta e uma éguas serviram como controle. No experimento I, a taxa de prenhez no ciclo seguinte a aspiração foi de 75% (grupo 1), 83,3% (grupo 2), 60% (grupo 3), e 73,3% (grupo 4). No experimento II foi de 76% no grupo aspirado e 77,4% no grupo controle (não aspirado). Em ambos os experimentos, as taxas de prenhez foram similares (P>0,05). Os resultados mostram que a taxa de concepção no primeiro ciclo após a aspiração folicular não é afetada pelo procedimento.

Pregnancy rates in Criollo breed mares after ultrasound-guided follicular aspiration / Taxa de gestação em éguas da raça crioula após aspiração folicular guiada por ultrassom

There are few studies about transvaginal ultrasound-guided follicle aspiration in equine medicine regarding potential complications to future fertility of aspirated mares. In order to evaluate the effect of follicular aspiration on subsequent fertility in mares, two experiments were conducted. In Experiment I, fifteen Criollo mares were allocated to one of three groups according to the diameter of the aspirated follicle during estrus: 25-29mm (n=4; Group 1); 30-34mm (n=6; Group 2); > 35mm (n=5; Group 3) and control group (n=15; Group 4). In Experiment II, the follicular aspiration was attempted in twenty-five mares during diestrous, when at least four follicles (> 5mm) were seen in the transrectal ultrasonography of both ovaries. All visible follicles, between 4 and 8 mm, were aspirated. Thirty-one mares served as control. In Experiments I and II, the pregnancy rates in the following cycle after aspiration were 75.0% (Group 1), 83.3% (Group 2), 60.0% (Group 3), and 73.3% (Group 4 - Control); and 76.0% in the aspirated diestrous group and 77.4% in the control group (non aspirated), respectively. On both experiments, pregnancy rates were similar (P>0.05) in treated and control mares. The results of this study show that the conception rates of the first estrus period following follicular aspiration are not affected by the procedure.(AU)

Há poucos estudos sobre aspiração folicular transvaginal guiada por ultrassom na medicina equina abordando complicações futuras na fertilidade das éguas aspiradas. Com o objetivo de avaliar o efeito da aspiração folicular na fertilidade das éguas, foram conduzidos dois experimentos. No experimento I, 15 éguas da raça Crioula foram distribuídas em três grupos de acordo com o diâmetro do folículo aspirado durante o estro: 25-29mm (n=4; grupo 1); 30-34mm (n=6; grupo 2); > 35mm (n=5; grupo 3) e grupo controle (n=15; grupo 4). No experimento II, a aspiração folicular foi realizada em 25 éguas durante o diestro quando pelo menos 4 folículos (>5mm) foram observados na ultrassonografia transretal em ambos os ovários. Foram aspirados todos os folículos visíveis, entre 4 e 8 mm. Trinta e uma éguas serviram como controle. No experimento I, a taxa de prenhez no ciclo seguinte a aspiração foi de 75% (grupo 1), 83,3% (grupo 2), 60% (grupo 3), e 73,3% (grupo 4). No experimento II foi de 76% no grupo aspirado e 77,4% no grupo controle (não aspirado). Em ambos os experimentos, as taxas de prenhez foram similares (P>0,05). Os resultados mostram que a taxa de concepção no primeiro ciclo após a aspiração folicular não é afetada pelo procedimento.(AU)

Pregnancy rates in criollo breed mares after ultrasound-guided follicular aspiration

There are few studies about transvaginal ultrasound-guided follicle aspiration in equine medicine regarding potential complications to future fertility of aspirated mares. In order to evaluate the effect of follicular aspiration on subsequent fertility in mares, two experiments were conducted. In Experiment I, fifteen Criollo mares were allocated to one of three groups according to the diameter of the aspirated follicle during estrus: 25-29mm (n=4; Group 1); 30-34mm (n=6; Group 2); > 35mm (n=5; Group 3) and control group (n=15; Group 4). In Experiment II, the follicular aspiration was attempted in twenty-five mares during diestrous, when at least four follicles (> 5mm) were seen in the transrectal ultrasonography of both ovaries. All visible follicles, between 4 and 8 mm, were aspirated. Thirty-one mares served as control. In Experiments I and II, the pregnancy rates in the following cycle after aspiration were 75.0% (Group 1), 83.3% (Group 2), 60.0% (Group 3), and 73.3% (Group 4 - Control); and 76.0% in the aspirated diestrous group and 77.4% in the control group (non aspirated), respectively. On both experiments, pregnancy rates were similar (P>0.05) in treated and control mares. The results of this study show that the conception rates of the first estrus period following follicular aspiration are not affected by the procedure.

Há poucos estudos sobre aspiração folicular transvaginal guiada por ultrassom na medicina equina abordando complicações futuras na fertilidade das éguas aspiradas. Com o objetivo de avaliar o efeito da aspiração folicular na fertilidade das éguas, foram conduzidos dois experimentos. No experimento I, 15 éguas da raça Crioula foram distribuídas em três grupos de acordo com o diâmetro do folículo aspirado durante o estro: 25-29mm (n=4; grupo 1); 30-34mm (n=6; grupo 2); > 35mm (n=5; grupo 3) e grupo controle (n=15; grupo 4). No experimento II, a aspiração folicular foi realizada em 25 éguas durante o diestro quando pelo menos 4 folículos (>5mm) foram observados na ultrassonografia transretal em ambos os ovários. Foram aspirados todos os folículos visíveis, entre 4 e 8 mm. Trinta e uma éguas serviram como controle. No experimento I, a taxa de prenhez no ciclo seguinte a aspiração foi de 75% (grupo 1), 83,3% (grupo 2), 60% (grupo 3), e 73,3% (grupo 4). No experimento II foi de 76% no grupo aspirado e 77,4% no grupo controle (não aspirado). Em ambos os experimentos, as taxas de prenhez foram similares (P>0,05). Os resultados mostram que a taxa de concepção no primeiro ciclo após a aspiração folicular não é afetada pelo procedimento.

Índice de prenhez com sêmen congelado de garanhões da raça Crioula usando glicerol ou dimetilformamida como crioprotetores / Pregnancy rates using frozen semen of Criollo stallions with glycerol or dimethylformamid as cryoprotectants

O índice de prenhez utilizando sêmen criopreservado de garanhões é variável e, além disso, algumas raças apresentam baixa congelabilidade. Foram inseminadas 104 éguas, divididas em dois experimentos, para avaliar a fertilidade do sêmen congelado de garanhões da raça Crioula (n=5), com 5% de dimetilformamida (DMF) ou 5% de glicerol (GLI), como crioprotetores. No Experimento I, as inseminações foram conduzidas pré-ovulação com sêmen fresco e criopreservado com DMF. No Experimento II, as éguas foram inseminadas pós-ovulação com sêmen fresco, DMF e GLI. As inseminações com sêmen congelado foram realizadas no ápice do corno uterino e as éguas do grupo controle foram inseminadas no corpo do útero com sêmen fresco. Para a avaliação  dos índices de prenhez dos grupos, utilizou-se um ciclo estral/animal. O diagnóstico de gestação foi realizado por meio de ultrassonografia transretal no 15º dia pós-ovulação. A motilidade média pós-descongelamento foi de 40% e 20%, respectivamente, para o sêmen congelado com DMF e GLI (P<0,05). Todos os garanhões tiveram motilidade superior no pós-descongelamento quando se utilizou a DMF. No Experimento I, o índice de prenhez foi de 12% (5/42) e 62% (20/32), respectivamente, para DMF e sêmen fresco (P<0,0001). No Experimento II, o índice de prenhez foi de 70% (7/10; P<0,05) para o sêmen fresco, 40% para o congelado com DMF (4/10; P<0,05) e 10% com GLI (1/10). A inseminação com sêmen congelado realizada com controle folicular mais frequente apresentou os melhores resultados. A baixa motilidade dos espermatozoides pós-descongelamento foi atribuída ao GLI utilizado no Experimento II. A DMF pode ser utilizada como uma alternativa ao congelamento do sêmen de garanhões da raça Crioula.

Pregnancy rates using stallions's frozen semen are variable; moreover, some breeds  present low freezability. One hundred and four (104) mares were inseminated and separeted into two experiments to evaluate fertility of frozen semens of Criollo stallions (n=5), with 5% of dimethylformamide (DMF) or 5% of glycerol (GLY) as cryoprotectants. In Experiment I, the inseminations were made during pre-ovulation with fresh and frozen semen with DMF. In Experiment II, the mares were inseminated during post-ovulation with fresh semen, DMF and GL. The inseminations with frozen semen were performed deep in the uterine horn ipsilateralis to the dominant follicle. Control mares were inseminated with fresh semen in the uterus. Only one estrus period per mare was used to evaluate the pregnancy rates of the groups. Pregnancy diagnosis through ultrasonography was performed on the 15th day post-ovulation. The mean post-thawing motility was 40% and 20%, respectively, for frozen semen with DMF and GLY (P<0.05). All stallions had higher post-thawing motility when using DMF. In Experiment I, pregnancy rates were 12% (5/42) and 62% (20/32), respectively for DMF and fresh semen (P<0.0001). In Experiment II, pregnancy rates were 40% (4/10), 10% (1/10) and 70% (7/10), respectively for DMF, GLY (P<0.05) and fresh semen (P<0.0001). Insemination with frozen semen performed with more frequent follicular control showed the best results. The low sperm motility after thawing was attributed to the GLY used in experiment II. The DMF can be used alternatively to Criollos Stallion’s semen feezing.

Índice de prenhez com sêmen congelado de garanhões da raça Crioula usando glicerol ou dimetilformamida como crioprotetores / Pregnancy rates using frozen semen of Criollo stallions with glycerol or dimethylformamid as cryoprotectants

O índice de prenhez utilizando sêmen criopreservado de garanhões é variável e, além disso, algumas raças apresentam baixa congelabilidade. Foram inseminadas 104 éguas, divididas em dois experimentos, para avaliar a fertilidade do sêmen congelado de garanhões da raça Crioula (n=5), com 5% de dimetilformamida (DMF) ou 5% de glicerol (GLI), como crioprotetores. No Experimento I, as inseminações foram conduzidas pré-ovulação com sêmen fresco e criopreservado com DMF. No Experimento II, as éguas foram inseminadas pós-ovulação com sêmen fresco, DMF e GLI. As inseminações com sêmen congelado foram realizadas no ápice do corno uterino e as éguas do grupo controle foram inseminadas no corpo do útero com sêmen fresco. Para a avaliação  dos índices de prenhez dos grupos, utilizou-se um ciclo estral/animal. O diagnóstico de gestação foi realizado por meio de ultrassonografia transretal no 15º dia pós-ovulação. A motilidade média pós-descongelamento foi de 40% e 20%, respectivamente, para o sêmen congelado com DMF e GLI (P<0,05). Todos os garanhões tiveram motilidade superior no pós-descongelamento quando se utilizou a DMF. No Experimento I, o índice de prenhez foi de 12% (5/42) e 62% (20/32), respectivamente, para DMF e sêmen fresco (P<0,0001). No Experimento II, o índice de prenhez foi de 70% (7/10; P<0,05) para o sêmen fresco, 40% para o congelado com DMF (4/10; P<0,05) e 10% com GLI (1/10). A inseminação com sêmen congelado realizada com controle folicular mais frequente apresentou os melhores resultados. A baixa motilidade dos espermatozoides pós-descongelamento foi atribuída ao GLI utilizado no Experimento II. A DMF pode ser utilizada como uma alternativa ao congelamento do sêmen de garanhões da raça Crioula.(AU)

Pregnancy rates using stallions's frozen semen are variable; moreover, some breeds  present low freezability. One hundred and four (104) mares were inseminated and separeted into two experiments to evaluate fertility of frozen semens of Criollo stallions (n=5), with 5% of dimethylformamide (DMF) or 5% of glycerol (GLY) as cryoprotectants. In Experiment I, the inseminations were made during pre-ovulation with fresh and frozen semen with DMF. In Experiment II, the mares were inseminated during post-ovulation with fresh semen, DMF and GL. The inseminations with frozen semen were performed deep in the uterine horn ipsilateralis to the dominant follicle. Control mares were inseminated with fresh semen in the uterus. Only one estrus period per mare was used to evaluate the pregnancy rates of the groups. Pregnancy diagnosis through ultrasonography was performed on the 15th day post-ovulation. The mean post-thawing motility was 40% and 20%, respectively, for frozen semen with DMF and GLY (P<0.05). All stallions had higher post-thawing motility when using DMF. In Experiment I, pregnancy rates were 12% (5/42) and 62% (20/32), respectively for DMF and fresh semen (P<0.0001). In Experiment II, pregnancy rates were 40% (4/10), 10% (1/10) and 70% (7/10), respectively for DMF, GLY (P<0.05) and fresh semen (P<0.0001). Insemination with frozen semen performed with more frequent follicular control showed the best results. The low sperm motility after thawing was attributed to the GLY used in experiment II. The DMF can be used alternatively to Criollos Stallions semen feezing.(AU)

Indução da ovulação com gonadotrofina coriônica humana em éguas Crioulas / Ovulation induction with human chorionic gonadotropin in criollo mares

The effect of age, follicular diameter and month of the breeding season (September to January) on the hCG induction of ovulation was evaluated using 123 Criollo mares. Age varied between two and 24 years and the animals were examined daily by rectal palpation and ultrasonography with a 5 MHz linear transducer. When ovarian follicles reached a diameter of 30 to 35 mm, ovulation was induced with an i.v. injection of 1000 IU (n = 39); 1500 IU (n = 41) or 2000 IU (n = 43) of hCG. The mares were bred the next day and examined daily until ovulation was detected. The percentage of mares ovulating before 24 h of hCG injection was 10.3%, 7.3% and 4.7%; until 48 h after injection 92.3%, 85.3% and 86.0% of the mares treated with 1000, 1500 and 2000 IU of hCG, respectively, ovulated. The month of the breeding season, age of the mares and follicular diameter had no influence on ovulatory response. The three hCG doses used in Criollo mares (P > 0.05) result in the induction of ovulation within 48 h after injection when a pre-ovulatory follicle with a 30 to 35 mm diameter was identified. A single dose of 1000 IU of hCG is efficient to induce ovulation in Criollo mares.

O efeito da idade, diâmetro folicular e mês da estação de monta (setembro a janeiro) na indução da ovulação com hCG foi avaliado em 123 éguas Crioulas. A idade das éguas variou entre dois e 24 anos e os animais foram examinados diariamente por palpação retal e ultrassonografia com transdutor linear de 5 MHz. Quando os folículos ovarianos atingiram diâmetro de 30 a 35 milímetros aplicou-se uma injeção intravenosa com 1000 UI (n = 39); 1500 UI (n = 41) ou 2000 UI (n = 43) de hCG. As éguas foram cobertas no dia seguinte e examinadas diariamente até a detecção da ovulação. O percentual de éguas que ovularam antes de 24 h da injeção de hCG foi de 10,3%, 7,3% e 4,7%, até 48h após a injeção foi de 92,3%, 85,3% e 86,0%, nos grupos com 1000, 1500 e 2000 UI de hCG, respectivamente. O mês da estação de monta, a idade das éguas ou o diâmetro folicular não influenciaram a resposta ovulatória. As três doses de hCG utilizadas em éguas Crioulas (P > 0,05) resultaram na indução da ovulação dentro de 48h após a aplicação, quando foi identificado um folículo pré-ovulatório de 30 a 35 mm de diâmetro. Uma única dose de 1000 UI de hCG é eficiente para induzir a ovulação em éguas Crioulas.

Indução da ovulação com gonadotrofina coriônica humana em éguas Crioulas / Ovulation induction with human chorionic gonadotropin in criollo mares

The effect of age, follicular diameter and month of the breeding season (September to January) on the hCG induction of ovulation was evaluated using 123 Criollo mares. Age varied between two and 24 years and the animals were examined daily by rectal palpation and ultrasonography with a 5 MHz linear transducer. When ovarian follicles reached a diameter of 30 to 35 mm, ovulation was induced with an i.v. injection of 1000 IU (n = 39); 1500 IU (n = 41) or 2000 IU (n = 43) of hCG. The mares were bred the next day and examined daily until ovulation was detected. The percentage of mares ovulating before 24 h of hCG injection was 10.3%, 7.3% and 4.7%; until 48 h after injection 92.3%, 85.3% and 86.0% of the mares treated with 1000, 1500 and 2000 IU of hCG, respectively, ovulated. The month of the breeding season, age of the mares and follicular diameter had no influence on ovulatory response. The three hCG doses used in Criollo mares (P > 0.05) result in the induction of ovulation within 48 h after injection when a pre-ovulatory follicle with a 30 to 35 mm diameter was identified. A single dose of 1000 IU of hCG is efficient to induce ovulation in Criollo mares.(AU)

O efeito da idade, diâmetro folicular e mês da estação de monta (setembro a janeiro) na indução da ovulação com hCG foi avaliado em 123 éguas Crioulas. A idade das éguas variou entre dois e 24 anos e os animais foram examinados diariamente por palpação retal e ultrassonografia com transdutor linear de 5 MHz. Quando os folículos ovarianos atingiram diâmetro de 30 a 35 milímetros aplicou-se uma injeção intravenosa com 1000 UI (n = 39); 1500 UI (n = 41) ou 2000 UI (n = 43) de hCG. As éguas foram cobertas no dia seguinte e examinadas diariamente até a detecção da ovulação. O percentual de éguas que ovularam antes de 24 h da injeção de hCG foi de 10,3%, 7,3% e 4,7%, até 48h após a injeção foi de 92,3%, 85,3% e 86,0%, nos grupos com 1000, 1500 e 2000 UI de hCG, respectivamente. O mês da estação de monta, a idade das éguas ou o diâmetro folicular não influenciaram a resposta ovulatória. As três doses de hCG utilizadas em éguas Crioulas (P > 0,05) resultaram na indução da ovulação dentro de 48h após a aplicação, quando foi identificado um folículo pré-ovulatório de 30 a 35 mm de diâmetro. Uma única dose de 1000 UI de hCG é eficiente para induzir a ovulação em éguas Crioulas.(AU)

Produção in vitro de embriões e Clonagem: um caminho conhecido? / Embryo in vitro production and cloning: a familiar pathway?

A produção in vitro de embriões é uma técnica que promove o avanço genético e incrementa o potencial reprodutivo com acasalamento de animais superiores. Adicionalmente, é uma alternativa para uso em fêmeas com disfunção reprodutiva e este fato permitiu que a técnica se expandisse da pesquisa para a aplicação comercial. Muitos “enigmas” ainda devem ser desvendados. A ovelha Dolly marcou o inicio de uma nova era na biotecnologia, levando também a clonagem a evoluir para o nível comercial. Estas biotécnicas, juntamente com a transgenia permitirão o melhoramento genético em menor tempo. O uso da clonagem e da transgenia para o tratamento de doenças humanas continua sendo o próximo grande desafio para o universo científico, político e cultural.

The in vitro embryo production is one of the techniques that promotes excellence in advanced genetic and enhance reproductive potential of superior breeding animals. Additionally, it is an alternative to overcome reproductive dysfunction in females. This fact is the main reason why the technique quickly expanded from research studies to a commercially scale. Many "mysteries" remain to be revealed. Dolly, the sheep, was the kick-off of a new era in biotechnology, leading to cloning up to the commercial level. These along with the transgenic biotechnology will allow for the genetic improvement in a shorter period of time. The use of cloning and transgenic techniques for the treatment of human diseases is still the next great challenge for the scientific community, under political and cultural guideline.

Produção in vitro de embriões e Clonagem: um caminho conhecido? / Embryo in vitro production and cloning: a familiar pathway?

A produção in vitro de embriões é uma técnica que promove o avanço genético e incrementa o potencial reprodutivo com acasalamento de animais superiores. Adicionalmente, é uma alternativa para uso em fêmeas com disfunção reprodutiva e este fato permitiu que a técnica se expandisse da pesquisa para a aplicação comercial. Muitos “enigmas” ainda devem ser desvendados. A ovelha Dolly marcou o inicio de uma nova era na biotecnologia, levando também a clonagem a evoluir para o nível comercial. Estas biotécnicas, juntamente com a transgenia permitirão o melhoramento genético em menor tempo. O uso da clonagem e da transgenia para o tratamento de doenças humanas continua sendo o próximo grande desafio para o universo científico, político e cultural. (AU)

The in vitro embryo production is one of the techniques that promotes excellence in advanced genetic and enhance reproductive potential of superior breeding animals. Additionally, it is an alternative to overcome reproductive dysfunction in females. This fact is the main reason why the technique quickly expanded from research studies to a commercially scale. Many "mysteries" remain to be revealed. Dolly, the sheep, was the kick-off of a new era in biotechnology, leading to cloning up to the commercial level. These along with the transgenic biotechnology will allow for the genetic improvement in a shorter period of time. The use of cloning and transgenic techniques for the treatment of human diseases is still the next great challenge for the scientific community, under political and cultural guideline.(AU)

Cultivo de embriões bovinos produzidos in vitro: efeito do número de embriões e da proporção de meio / Culture of in vitro produced bovine embryos: effect of number of embryos and medium ratio

Na última década, os produtores de leite e carne bovina incrementaram consideravelmente o uso da aspiração folicular (OPU) associada à produção in vitro de embriões (IVP). Oócitos recuperados pela OPU têm qualidade diversificada e seu número reduzido requer condições diferenciadas de cultivo para a IVP Para determinar o efeito do número de embriões e volume de meio sobre a IVP, 1428 embriões bovinos foram cultivados em grupos de 5, 10 e 20, em 1:1, 1:5 e 1:10mL de meio, Grupos de 20 oócitos foram maturados in vitro em 200mL de TCM-199+ rFSHh+ 10% de soro de vaca em estro (SVE), por 24h. A fecundação in vitro foi em grupos de 20 oócitos / 200mL de meio Fert-Talp, por 18h com 1x10 elevado a 6ª espermatozóides/mL. O cultivo foi em SOFaaci+5% SVE por 8 dias. Considerando-se o dia da fecundação como D0, conduziu-se as avaliações no D2 (clivagem), D7 (blastocistos) e no D9 (eclosão). A taxa de clivagem foi superior quando o cultivo foi com 20 embriões e não foi afetada quando a proporção de meio variou (1:1; 1:5 e 1:10). Com as proporções de meio de cultivo 1:5 ou 1:10, a taxa de embriões em D7 foi superior (P<0.05) à 1:1. O número de embriões cultivados influenciou a produção de blastocistos em D7 (P<0,05) com 20 embriões/gota, Estes resultados também se refletem nos percentuais de blastocistos eclodidos em D9, sendo que 1:5 e 1:10 foram superiores (P<0,05) à 1:1. Da mesma forma, a taxa de eclosão foi superior (P<0,05) com o cultivo de 10 ou 20 embriões/gota quando comparado ao grupo de 5 embriões/gota. A redução do número de embriões e da proporção de volume de meio no cultivo, afeta os índices de desenvolvimento na produção in vitro de embriões bovinos.

In the last decade the dairy and beef bovine farms had an increment in their breeding programs that inc1ude the use o ovum pick-up and in vitro production (OPU /IVP). Oocytes retrieved by OPU vary in quality and its reduced number requires appropriated culture conditions for IVP. To evaluate the effect of the number of embryos and volume of the media in the in vitro culture of bovine embryos, 1428 zygotes were culturedingroups of 5, 10 or 20 in 1, 5 or 10mLof medium. Groups of 20 oocytes matured in vitro in 200mL of TCM+rFSHh+ 10% estrus cow serum (ECS). The fertilization was performed in groups of 20 oocytes/200mL of Fert-Talp medium, for 18h with 1x10 6ª spermatozoa/mL. The culture was done in SOFaaci+5% ECS for 8 days. Considering D0 as the fertilization day, the IVP was evaluated on day 2 (cleavage), day 7 (blastocyst) and in day 9 (hatching rates). The cleavage rates were higherwhen embryos were cultured in groups of twenty. However, it was not affected by the medium ratio of 1:1,1:5 and 1:10. The use of 1:5 and 1:10mL of culture medium ratio showed higher embryo production rates in D7 (P<0.05) than 1:1 mL proporcion. The culture of 20 embryos per drop affected the blastocyst production on day 7. Likewise the hatching rates in D9 were higher with 1:5 and 1:10 than 1:1. Similarly, the hatching rates were higher in cultured of 10 or 20 embryos/drop when compared to groups of 5 embryos/ drop. The reduction of embryos and the proportion of the medium volume in culture affects the development indexes on bovine embryos in vitro production.