Ovarian follicular dynamics in 2 to 3 months old Nelore calves (Bos taurus indicus)

This study aimed to evaluate reproductive physiology aspects in 2 to 3 months old Nelore (Bos taurus indicus) calves. Follicular dynamics was monitored daily by ultrasound in ten calves during 18 consecutive days. Calves younger than 2.25 months old (n = 4) had maximum follicle diameters ≤2.5 mm, so only the other animals (n = 6) continued to be monitored by ultrasound. The mean maximum diameter of the ovaries was 13.6 ± 0.6 mm, which had 31.4 ± 3.45 visible follicles. A successive anovulatory follicular wave-like pattern was identified when each wave showed a dominant follicle, including a variable number of other follicles smaller in size (subordinate follicles), during the observational period. Three consecutive follicular growth waves were detected per animal, during this time interval, when 50% of the animals (n = 3) showed two waves and the other half (n = 3) had three waves. The first day of detection of the dominant follicle, retrospectively identified at a diameter of 2 mm, was defined as the day of wave emergence on each wave (day zero). Considering the grouped data, the follicular wave length was 9.2 ± 2.0 days and the correlated dominant follicle began its regression at 6.33 ± 1.63 days after the day of its emergence. The dominant follicles had a growth rate of 0.23 ± 0.06 mm/day and reached the maximum diameter of 3.03 ± 0.17 mm. Despite the smaller ovarian and follicle diameters in 2 to 3 months old Nelore calves (Bos taurus indicus) compared to studies in post pubertal females; the follicular wave-like pattern and the number of recruited follicles were similar to the reported in Zebu females in reproductive activity. These data can characterize an early critical moment on the reproductive development of these animals.

Ovarian follicular dynamics in 2 to 3 months old Nelore calves (Bos taurus indicus)

This study aimed to evaluate reproductive physiology aspects in 2 to 3 months old Nelore (Bos taurus indicus) calves. Follicular dynamics was monitored daily by ultrasound in ten calves during 18 consecutive days. Calves younger than 2.25 months old (n = 4) had maximum follicle diameters ≤2.5 mm, so only the other animals (n = 6) continued to be monitored by ultrasound. The mean maximum diameter of the ovaries was 13.6 ± 0.6 mm, which had 31.4 ± 3.45 visible follicles. A successive anovulatory follicular wave-like pattern was identified when each wave showed a dominant follicle, including a variable number of other follicles smaller in size (subordinate follicles), during the observational period. Three consecutive follicular growth waves were detected per animal, during this time interval, when 50% of the animals (n = 3) showed two waves and the other half (n = 3) had three waves. The first day of detection of the dominant follicle, retrospectively identified at a diameter of 2 mm, was defined as the day of wave emergence on each wave (day zero). Considering the grouped data, the follicular wave length was 9.2 ± 2.0 days and the correlated dominant follicle began its regression at 6.33 ± 1.63 days after the day of its emergence. The dominant follicles had a growth rate of 0.23 ± 0.06 mm/day and reached the maximum diameter of 3.03 ± 0.17 mm. Despite the smaller ovarian and follicle diameters in 2 to 3 months old Nelore calves (Bos taurus indicus) compared to studies in post pubertal females; the follicular wave-like pattern and the number of recruited follicles were similar to the reported in Zebu females in reproductive activity. These data can characterize an early critical moment on the reproductive development of these animals.(AU)

Antioxidantes associados à pressão hidrostática sobre a viabilidade embrionária pós-desvitrificação / Association between antioxidant and hidrostatic pressure on the embryonic viability after

Avaliou-se o efeito de dois antioxidantes no cultivo de embriões pós-desvitrificação, associados ounão à pressão hidrostática (PH) em três experimentos. O primeiro avaliou a interação entre PH e antioxidante(β-mercaptoetanol - BME, cisteamina - CYST e BME + CYST). O segundo, similar ao primeiro, vitrificou osembriões uma hora após passarem ou não pela PH. Os parâmetros foram taxas de eclosão e degeneração com24 e 48 h após passar pela PH (experimento 1) e 12, 24, 48 e 72 h pós-desvitrificação (experimento 2). Oexperimento 3 avaliou a taxa de prenhez de embriões cultivados por 12 h com/sem BME. O primeiroexperimento não demonstrou interação entre os tratamentos. No segundo, os resultados foram similares para BX.O tratamento BME + CYST obteve melhor taxa de eclosão dos BL com 48 e 72 h (76,04%). O mesmo fatoocorreu para a taxa de degeneração às 24 h (BME + CYST = 7,29%; 32,29% controle). Ao transferir os embriões(n = 55), percebeu-se uma similaridade em todos os grupos (38,9% CONT; 16,7% VITRIF e 31,6% BME). Opresente trabalho mostrou que o uso da pressão hidrostática e de BME e CYST não influencia as taxas deeclosão, degeneração e de prenhez de embriões vitrificados.(AU)

This study aimed to evaluate different antioxidants in embryo culture after vitrification, with or withoutthe previous use of hydrostatic pressure (PH). Three experiments were designed to evaluate the interactionbetween PH and antioxidants (β-mercaptoethanol - BME, cysteamine - CYST and BME + CYST) in fresh andvitrified in vitro produced embryos. In experiment 1 hatching and degeneration rates were evaluated at 24 and48 h after passing through the PH and in experiment 2 the same parameters were evaluated at 12, 24, 48 and72 h after heating. The last step of the study evaluated the pregnancy rate of vitrified embryos, cultured for 12 hwith / without BME. The first experiment showed no difference between treatments. The second found similarresults for all parameters evaluated in BX embryos. Note that the BME + CYST treatment obtained a betterhatching rate in BL with 48 and 72 h (76.04%) than the control group (45.83%). The same behavior wasobserved in degeneration 24 h, where the BME + CYST group was 7.29% against 32.29% in the control.However, the pregnancy rates (55 embryo transfers) were not different between control fresh, control vitrifiedand BME groups (38.9%, 16.7% and 31.6%, respectively). This study showed that the use of hydrostaticpressure and antioxidant had no effect on the evaluated parameters.(AU)

Antioxidantes associados à pressão hidrostática sobre a viabilidade embrionária pós-desvitrificação / Association between antioxidant and hidrostatic pressure on the embryonic viability after

Avaliou-se o efeito de dois antioxidantes no cultivo de embriões pós-desvitrificação, associados ounão à pressão hidrostática (PH) em três experimentos. O primeiro avaliou a interação entre PH e antioxidante(β-mercaptoetanol - BME, cisteamina - CYST e BME + CYST). O segundo, similar ao primeiro, vitrificou osembriões uma hora após passarem ou não pela PH. Os parâmetros foram taxas de eclosão e degeneração com24 e 48 h após passar pela PH (experimento 1) e 12, 24, 48 e 72 h pós-desvitrificação (experimento 2). Oexperimento 3 avaliou a taxa de prenhez de embriões cultivados por 12 h com/sem BME. O primeiroexperimento não demonstrou interação entre os tratamentos. No segundo, os resultados foram similares para BX.O tratamento BME + CYST obteve melhor taxa de eclosão dos BL com 48 e 72 h (76,04%). O mesmo fatoocorreu para a taxa de degeneração às 24 h (BME + CYST = 7,29%; 32,29% controle). Ao transferir os embriões(n = 55), percebeu-se uma similaridade em todos os grupos (38,9% CONT; 16,7% VITRIF e 31,6% BME). Opresente trabalho mostrou que o uso da pressão hidrostática e de BME e CYST não influencia as taxas deeclosão, degeneração e de prenhez de embriões vitrificados.

This study aimed to evaluate different antioxidants in embryo culture after vitrification, with or withoutthe previous use of hydrostatic pressure (PH). Three experiments were designed to evaluate the interactionbetween PH and antioxidants (β-mercaptoethanol - BME, cysteamine - CYST and BME + CYST) in fresh andvitrified in vitro produced embryos. In experiment 1 hatching and degeneration rates were evaluated at 24 and48 h after passing through the PH and in experiment 2 the same parameters were evaluated at 12, 24, 48 and72 h after heating. The last step of the study evaluated the pregnancy rate of vitrified embryos, cultured for 12 hwith / without BME. The first experiment showed no difference between treatments. The second found similarresults for all parameters evaluated in BX embryos. Note that the BME + CYST treatment obtained a betterhatching rate in BL with 48 and 72 h (76.04%) than the control group (45.83%). The same behavior wasobserved in degeneration 24 h, where the BME + CYST group was 7.29% against 32.29% in the control.However, the pregnancy rates (55 embryo transfers) were not different between control fresh, control vitrifiedand BME groups (38.9%, 16.7% and 31.6%, respectively). This study showed that the use of hydrostaticpressure and antioxidant had no effect on the evaluated parameters.

S-adenosil-L-homocisteína como substância desmetilante de DNA no cultivo de células / S-adenosyl-L-homocysteine as DNA demethylating substance in nucleus donor cells culture

Fatores epigenéticos são responsáveis por controlar a expressão de genes e a diferenciação durante a vida celular. Entre eles, a metilação do DNA é o mais estudado. Cada tipo celular possui um padrão epigenético altamente especializado. Após a fecundação natural ou a clonagem por transferência nuclear (SCNT), um padrão epigenético preexistente deve ser apagado e restabelecido para garantir o correto desenvolvimento embrionário. Porém, nos clones, essa reprogramação é ineficiente, mas é possível que o uso de substâncias desmetilantes de DNA utilizadas durante o cultivo celular de células doadoras de núcleo possa desmetilar o DNA, aumentando a eficiência da técnica. (AU)

Epigenetic factors are responsible for controlling gene expression and differentiation through the cell life. Among them, DNA methylation is the most studied. Each cell type possesses a specific and highly specialized epigenetic pattern. After natural fertilization or cloning by somatic cell nuclear transfer (SCNT), a pre-existing epigenetic pattern must be erased and reestablished to ensure correct embryo development. However, in cloning this reprogramming is inefficient and it is possible that the use of a DNA demethylating substance can improve the efficiency of the technique. (AU)

S-adenosil-L-homocisteína como substância desmetilante de DNA no cultivo de células / S-adenosyl-L-homocysteine as DNA demethylating substance in nucleus donor cells culture

Fatores epigenéticos são responsáveis por controlar a expressão de genes e a diferenciação durante a vida celular. Entre eles, a metilação do DNA é o mais estudado. Cada tipo celular possui um padrão epigenético altamente especializado. Após a fecundação natural ou a clonagem por transferência nuclear (SCNT), um padrão epigenético preexistente deve ser apagado e restabelecido para garantir o correto desenvolvimento embrionário. Porém, nos clones, essa reprogramação é ineficiente, mas é possível que o uso de substâncias desmetilantes de DNA utilizadas durante o cultivo celular de células doadoras de núcleo possa desmetilar o DNA, aumentando a eficiência da técnica.

Epigenetic factors are responsible for controlling gene expression and differentiation through the cell life. Among them, DNA methylation is the most studied. Each cell type possesses a specific and highly specialized epigenetic pattern. After natural fertilization or cloning by somatic cell nuclear transfer (SCNT), a pre-existing epigenetic pattern must be erased and reestablished to ensure correct embryo development. However, in cloning this reprogramming is inefficient and it is possible that the use of a DNA demethylating substance can improve the efficiency of the technique.

Reprogramação epigenética em gametas e embriões de mamíferos / Epigenetic reprogramming in gametes and embryos of mammals

A epigenética refere-se aos processos que regulam a atividade gênica e que não estão relacionados à sequência primária do DNA. Um evento importante e específico que ocorre em gametas é uma extensa reprogramação epigenética pela qual passam essas células para estarem aptas à fecundação e à formação de um embrião viável. Quanto melhor se compreender sobre a reprogramação epigenética que acontece durante a gametogênese e a embriogênese inicial, maior será a capacidade de se desenvolver melhores sistemas de produção de embriões.(AU)

Epigenetics is the study of factors that regulate gene expression and that are not related to the primary sequence of DNA. An important and specific event that happens in gametes is an extensive epigenetic reprogramming, which is essential to produce viable gametes and embryos. The better understanding this epigenetic reprogramming that occurs in gametogenesis and embryogenesis is necessary to develop better systems of embryo production.(AU)

Reprogramação epigenética em gametas e embriões de mamíferos / Epigenetic reprogramming in gametes and embryos of mammals

A epigenética refere-se aos processos que regulam a atividade gênica e que não estão relacionados à sequência primária do DNA. Um evento importante e específico que ocorre em gametas é uma extensa reprogramação epigenética pela qual passam essas células para estarem aptas à fecundação e à formação de um embrião viável. Quanto melhor se compreender sobre a reprogramação epigenética que acontece durante a gametogênese e a embriogênese inicial, maior será a capacidade de se desenvolver melhores sistemas de produção de embriões.

Epigenetics is the study of factors that regulate gene expression and that are not related to the primary sequence of DNA. An important and specific event that happens in gametes is an extensive epigenetic reprogramming, which is essential to produce viable gametes and embryos. The better understanding this epigenetic reprogramming that occurs in gametogenesis and embryogenesis is necessary to develop better systems of embryo production.

Tétano em pequenos ruminantes: estudo retrospectivo dos principais achados clínico-epidemiológicos em 11 casos / Tetanus in small ruminants: retrospective study of major clinical and epidemiological findings in 11 cases

A retrospective study of major clinical and epidemiological findings was performed in 11 cases of tetanus observed in eight sheep and three goats from 1998 to 2008. The cases occurred predominantly in animals aging from five days to two years, in winter season, with history of recent wounds or surgical procedures. Muscle rigidity and muscular tremors (72.0%), tachycardia/dyspnea (54.5%), change of placement of ears (45.4%), protusion of the third eyelid (27.2%), hypersensitivity to external stimulus (18.1%), and elevation of ears (18.1%) were the most common clinical signs.

Tétano em pequenos ruminantes: estudo retrospectivo dos principais achados clínico-epidemiológicos em 11 casos

A retrospective study of major clinical and epidemiological findings was performed in 11 cases of tetanus observed in eight sheep and three goats from 1998 to 2008. The cases occurred predominantly in animals aging from five days to two years, in winter season, with history of recent wounds or surgical procedures. Muscle rigidity and muscular tremors (72.0%), tachycardia/dyspnea (54.5%), change of placement of ears (45.4%), protusion of the third eyelid (27.2%), hypersensitivity to external stimulus (18.1%), and elevation of ears (18.1%) were the most common clinical signs.

Molecular identification and thermoresistance to boiling of Nocardia farcinica and Nocardia cyriacigeorgica from bovine bulk tank milk

Two strains of Nocardia spp. were isolated from bovine milk of two individual bulk tank. Molecular identification classified the strains as Nocardia farcinica and Nocardia cyriacigeorgica. The thermorresistance to boiling of the isolates was carried out and was observed bacterial growth after boiling. Our findings indicate the potential risk of pathogen transmission to humans through contaminated milk with Nocardia spp.

Inativação do cromossomo X em mamíferos / X- Chromosome inactivation in mammals

Fêmeas de mamíferos possuem dois cromossomos X, enquanto machos possuem apenas um. Isto levou à evolução de um mecanismo de compensação de dose chamado de inativação do cromossomo X, um importante evento epigenético que deve ocorrer em embriões fêmeas de todos os mamíferos. Durante a embriogênese, um dos dois cromossomos X é aleatoriamente inativado em cada célula da massa celular interna, preferencialmente o cromossomo X paterno no trofoblasto, formando indivíduos adultos que são mosaicos de dois tipos de células, expressando um ou outro cromossomo X. (AU)

Mammalian females have two X chromosomes and males only one. This led to the creation of an evolutionary mechanism of dosage compensation, called the X-chromosome inactivation, an important epigenetic event that must occur in female embryos of all mammals. During embryogenesis, one of the two X chromosomes is randomly inactivated in each cell of the inner cell mass, and preferably the paternal X chromosome in trophoblast, turning into adult mosaics of two cell types, expressing either X chromosome.(AU)

Inativação do cromossomo X em mamíferos / X- Chromosome inactivation in mammals

Fêmeas de mamíferos possuem dois cromossomos X, enquanto machos possuem apenas um. Isto levou à evolução de um mecanismo de compensação de dose chamado de inativação do cromossomo X, um importante evento epigenético que deve ocorrer em embriões fêmeas de todos os mamíferos. Durante a embriogênese, um dos dois cromossomos X é aleatoriamente inativado em cada célula da massa celular interna, preferencialmente o cromossomo X paterno no trofoblasto, formando indivíduos adultos que são mosaicos de dois tipos de células, expressando um ou outro cromossomo X.

Mammalian females have two X chromosomes and males only one. This led to the creation of an evolutionary mechanism of dosage compensation, called the X-chromosome inactivation, an important epigenetic event that must occur in female embryos of all mammals. During embryogenesis, one of the two X chromosomes is randomly inactivated in each cell of the inner cell mass, and preferably the paternal X chromosome in trophoblast, turning into adult mosaics of two cell types, expressing either X chromosome.

Estudo dos métodos de rotina diagnóstica de mastite no leite de éguas / Study of routine diagnosis methods of mastitis in mares

Routine diagnosis methods used in bovine mastitis were studied in 55 mares in lactation. The findings of strip cup test, California Mastitis Test-CMT, electronic somatic cell count-CCS, microbiological culture, and in vitro antimicrobial susceptibility profile of isolates were discussed. Streptococcus spp., Staphylococcus spp, and enterobacteria were the most common microorganisms isolated in health and CMT-positive mammary glands. Staphylococcus aureus and Arcanobacterium pyogenes were identified in two mares presenting clinical mastitis. Mean somatic cell count of eight mares without presence of microorganisms in milk was 247.57x10³/mL and 1.621,86x10³/mL in 47 mares with positive microbiological culture. Moderate concordance (63.8 percent) between positive reactions in CMT (1 to 3+) and microbiological culture was observed. Amicacin (78.9 percent), ceftiofur (74.7 percent), sulpha-trimetoprim (69,0 percent) and norfloxacin (69.0 percent), were the most effective drugs, while resistance of isolates was mainly observed against penicillin (64.8 percent), gentamycin (35.2 percent), azithromycin (35.2 percent), enrofloxacin (28.2 percent), and florfenicol (28.2 percent).(AU)