Maria Lúcia Gambarini

The Mare Model to Study the Effects of Ovarian Dynamics on Preantral Follicle Features

Ovarian tissue collected by biopsy procedures allows the performance of many studies with clinical applications in the field of female fertility preservation. The aim of the present study was to investigate the influence of reproductive phase (anestrous vs. diestrous) and ovarian structures (antral follicles and corpus luteum) on the quality, class distribution, number, and density of preantral follicles, and stromal cell density. Ovarian fragments were harvested by biopsy pick-up procedures from mares and submitted to histological analysis. The mean preantral follicle and ovarian stromal cell densities were greater in the diestrous phase and a positive correlation of stromal cell density with the number and density of preantral follicles was observed. The mean area (mm2) of ovarian structures increased in the diestrous phase and had positive correlations with number of preantral follicles, follicle density, and stromal cell density. Biopsy fragments collected from ovaries containing an active corpus luteum had a higher follicle density, stromal cell density, and proportion of normal preantral follicles. In conclusion, our results showed: (1) the diestrous phase influenced positively the preantral follicle quality, class distribution, and follicle and stromal cell densities; (2) the area of ovarian structures was positively correlated with the follicle and stromal cell densities; and (3) the presence of an active corpus luteum had a positive effect on the quality of preantral follicles, and follicle and stromal densities. Therefore, herein we demonstrate that the presence of key ovarian structures favors the harvest of ovarian fragments containing an appropriate number of healthy preantral follicles.

Ovarian activity and oocyte quality associated with the biochemical profile of serum and follicular fluid from Girolando dairy cows postpartum

This study was designed to evaluate the influence of heat stress (HS) on the metabolic profile of serum and follicular fluid (FF), ovarian follicle development, and oocyte quality of Girolando dairy cows. Oocytes, blood, and FF (follicles ≥9mm) samples were obtained at 30, 45, 60, 75, and 90 days postpartum in the summer and winter seasons. During transvaginal follicular aspiration, rectal temperature (RT), body condition score (BCS), number of ovarian follicles, and quality of oocytes were recorded. The ambient air temperature (AT) and relative humidity (RH) were also recorded to calculate the temperature humidity index (THI). Glucose, total cholesterol (TC), triglycerides (TG), urea, sodium (Na), potassium (K), and calcium (Ca) concentrations were determined using serum and FF samples. The RT, THI, and BCS loss were greater (P<0.01) in the summer; however, glucose, Na, and K serum concentrations decreased in the same season (P<0.05). Degenerated oocytes were positively associated (P<0.05) with THI (r=0.14) and AT (r=0.13), and negatively associated with glucose (r=-0.12) and K (r=-0.11) serum concentrations. HS induces metabolic changes, which compromise the number of ovarian follicles and the follicular environment, thus resulting in morphologically damaged oocytes.

Preantral follicle density in ovarian biopsy fragments and effects of mare age

The aims of the present study were to: (1) evaluate preantral follicle density in ovarian biopsy fragments within and among mares; (2) assess the effects of mare age on the density and quality of preantral follicles; and (3) determine the minimum number of ovarian fragments and histological sections needed to estimate equine follicle density using a mathematical model. The ovarian biopsy pick-up method was used in three groups of mares separated according to age (5-6, 7-10 and 11-16 years). Overall, 336 preantral follicles were recorded with a mean follicle density of 3.7 follicles per cm2. Follicle density differed (P < 0.05) among animals, ovarian fragments from the same animal, histological sections and age groups. More (P < 0.05) normal follicles were observed in the 5-6 years (97%) than the 11-16 years (84%) age group. Monte Carlo simulations showed a higher probability (90%; P < 0.05) of detecting follicle density using two experimental designs with 65 histological sections and three to four ovarian fragments. In summary, equine follicle density differed among animals and within ovarian fragments from the same animal, and follicle density and morphology were negatively affected by aging. Moreover, three to four ovarian fragments with 65 histological sections were required to accurately estimate follicle density in equine ovarian biopsy fragments.

Aspectos físicos químicos e microbiológicos da urina de matrizes suínas descartadas

The present study describes the physical-chemical alterations of the urine and identifies etiological agents of the urine of 35 sows. Out of 35 samples, 16 (45.7%) were positive for nitrite and/or blood, positive for urinary infection (UI); eight (50%) were dark yellow and six (37.5%) had clear yellow coloration; in two (12.5%) samples did not show any alteration. Ten samples had ammonia smell, seven among them were positive for UI. Other findings were turbid urine and turbid with grumes, normal pH values (5.5 – 6.5) and densities higher than 1012. Microorganisms were isolated in 91.5% out of 35 urine samples, with prevalence of Escherichia coli (45.7%). In 11 samples (31.4%) Actinobaculum suis was isolated, four were simultaneously positive for UI and Actinobaculum suis; seven were negative for UI, but it was observed the presence of Actinobaculum suis in the indirect immunofluorescence.

Metabolic profile of serum and follicular fluid from postpartum dairy cows during summer and winter.

This study was designed to monitor the biochemical profiles of serum and follicular fluid (FF) of postpartum dairy cows during the summer (n=30) and winter (n=30). Blood and FF (follicles ≥ 9 mm) were obtained from Girolando cows at 30, 45, 60, 75 and 90 days postpartum. The samples were collected and analysed to determine glucose, total cholesterol (TC), triglyceride (TG), urea, sodium (Na), potassium (K) and calcium (Ca) levels. Throughout the study, the following clinical variables were measured: rectal temperature (RT), respiratory rate (RR) and body condition score (BCS). In addition, the temperature humidity index (THI) was calculated for each season. During the summer season, THI was higher, BCS decreased, there was an increase in RT, and glucose, urea, Na and K serum levels were decreased (P<0.05). The levels of TC, TG, urea, K and Ca in follicular fluid increased (P<0.05). Positive correlations (P<0.05) were observed between the serum and FF levels for glucose (r=0.29), TC (r=0.24) and Ca (r=0.30). Therefore, the biochemical profile of serum and FF of dairy cows under summer heat-stress conditions demonstrates marked changes that may impair fertility during lactation.

Embryonic stem-like cells derived from in vitro produced bovine blastocysts

The aim of this work was to study the derivation of bovine embryonic stem-like (ES-like) cells from the inner cell mass (ICM) of in vitro produced blastocysts. The ICMs were mechanically isolated and six out of seventeen (35%) ICMs could attach to a monolayer of murine embryonic fibroblasts (MEF). Ten days after, primary outgrowths were mechanically dissected into several small clumps and transferred to a new MEF layer. Cells were further propagated and passaged by physical dissociation over a 60 days period. The pluripotency of the bovine ES-like cells was confirmed by RT-PCR of Oct-4 and STAT-3 gene markers. The colonies were weakly stained for alkaline phosphatase and the mesoderm and endoderm differentiation gene markers such as GATA-4 and Flk-1, respectively, were not expressed. Embryoid bodies were spontaneously formed at the seventh passage. Results showed that bovine ES-like cells could be obtained and passaged by mechanical procedures from the fresh in vitro produced blastocysts.

Suplementação de bezerros lactentes em cocho privativo: Revisão

The beef market in Brazil has undergone great changes which directly affect the rural producer. Consumer markets have required products with best quality. Thereat, the systems of creation are evolving to allow the animals being slaughtered younger and with higher weights. The rural properties have wanted fit on this new reality, being that properties as perform calf creates phase they begin to have great importance on the supply chain meat. These need to adopt new techniques that allow the weaning of calves heaviest and greater uniformity on the batch, facilitating the working next phase, the rebuilds. The use of a differentiated and private diet there for the calves on the lactating phase it’s an alternative to achieve the production goal of superior animals at weaning.

Assessment of cow and farm level risk factors associated with Ureaplasma diversum in pasture-based dairy systems - A field study

Potential risk factors for Ureaplasma diversum in the vaginal mucus of 1,238 dairy cows were included in a multivariate logistic regression model, based on the cow level (i.e., granular vulvovaginitis [+GVV], yearly milk production [4500 kg or more], pregnancy, predominance of Bos taurus [+Bos Taurus], score of corporal condition [at least 2.5], concomitant positivity for Escherichia coli [+E.coli]), and farm level i.e., milking room hygiene (-Milking room), dunghill location, and replacement female). Ureaplasma diversum was present in 41.1% of the samples. Independent risk factors for U. diversum were +GVV (odds ratio [OR], 1.31); +Mycoplasma spp (OR, 5.67); yearly milk production (4500 kg or more) (OR, 1.99); +Bos taurus (OR, 1.68); +E. coli (OR, 4.96); -milking room (OR, 2.31); and replacement females (OR, 1.89). Ureaplasma diversum vaginal colonization was strongly associated with Mycoplasma spp., E. coli, and number of pregnant cows.

Pico pré-ovulatório de LH em fêmeas Nelore (Bos taurus indicus) sincronizadas

Desenvolveu-se este trabalho com o objetivo de avaliar a frequencia de pulsos e a amplitude do pico pre-ovulatorio do hormonio luteinizante (LH) de novilhas e vacas Nelore submetidas a um protocolo hormonal. Em seis femeas de cada categoria utilizou-se o seguinte protocolo: colocacao do implante de norgestomet (NOR) e aplicacao de 2,0 mg de benzoato de estradiol (BE) no dia zero, com retirada apos oito dias, seguida da aplicacao de 0,5 mg de cloprostenol sodico. Apos 24 horas (dia nove) 1,0 mg de BE. As colheitas de sangue iniciaram-se 27,00 horas apos a aplicacao da segunda dose de BE, sendo repetidas a cada 15 minutos por um periodo de seis horas. A determinacao dos niveis sericos de LH foi feita pelo metodo de radioimunoensaio. Em uma novilha e em quatro vacas pode-se observar o pico pre-ovulatorio de LH. Na novilha o pico foi verificado na primeira colheita, 27,00 horas apos a inducao da ovulacao. Nas vacas este ocorreu, em media, 28,20±0,55 horas apos a aplicacao do BE. A amplitude maxima verificada foi, em media, de 4,58±0,67 ng/ml. Nos animais em que nao se observou o pico de LH, as concentracoes medias foram de 0,90±0,03 ng/ml para as novilhas e de 0,86±0,03 ng/ml para as vacas. Sugere-se que nas novilhas o pico pre-ovulatorio de LH, provavelmente, tenha ocorrido mais precocemente que nas vacas. No entanto, sao necessarios mais estudos sobre o momento do pico de LH em femeas bovinas com ovulacao sincronizada.