Association among calving season and measures of energy status, resumption of ovulation and subclinical endometritis in early lactating dairy cows

A total of 65 multiparous cows that calved during the hot season (n = 21), temperate season (n = 23) or cold season (n = 21) were used to investigate the relationships between heat stress, seasonal changes, metabolic traits, body condition score (BCS), resumption of ovulation and occurrence of subclinical endometritis (SE). Cows were monitored for the first 7 weeks of lactation by ultrasonographic examination. Blood sampling and BCS evaluations were performed on a weekly basis. Plasma progesterone (P4) and blood metabolites related to energy status including  -hydroxybutyrate, nonesterified fatty acids, total cholesterol, blood glucose and blood urea nitrogen were analyzed. Resumption of ovulation postpartum was confirmed by the first detection of a corpus luteum or a rise in P4 ≥ 1 ng/ml. Moreover, subclinical endometritis was diagnosed by brush cytology on day 40 ± 2 of lactation and cows having polymorphonuclear cell percentages (PMN%) ≥ 5 were considered SE positive. As expected, mean temperatur e humidity index differed (P < 0.001) among hot (75-85), temperate (50-65) and cold seasons (35-45). The BCS in cows that calved during the hot season was lower (P < 0.001) when compared with those that calved during the cold and temperate seasons. The percentage of cows that resumed ovulation in the first 45 days of lactation was greater (P < 0.05) for those that calved during the hot season (90%) than the temperate season (60%). The concentration of NEFA was greater (P < 0.05) for cows that calved during th e cold season than the hot season during different weeks postpartum. The concentration of glucose in weeks 4 to 7 postpartum was greater (P < 0.01) for cows that calved during the temperate season when compared to cows that calved during the hot season. Ther e was no difference in the prevalence of SE according to calving season. The percentage of PMN tended (P < 0.1) to be greater in cows with SE during the te mperate season than during the hot season. In conclusion, calving season may influence BCS, blood metabolites and resumption of ovulation whereas no association with prevalence of subclinical endometritis was observed.

Efectos de la selección y de la superovulación en las pérdidas gestacionales de ratonas CF1 / Effects of selection and superovulation on gestational losses in CF1 mice

En un par de líneas de ratones seleccionadas para alto (s') y bajo peso (s), originadas a partir de una población no seleccionada de la cepa CF1 (t), se modificó la estructura ovárica. El diámetro de los folículos ováricos y el número de folículos y de cuerpos lúteos se incrementaron en las hembras de la línea s', sin expresarse en un mayor tamaño de camada al nacimiento, posiblemente, por un aumento de las pérdidas gestacionales. Se probó si los efectos conjuntos de la selección de peso a largo plazo y de la estimulación ovárica incrementaban las pérdidas gestacionales. Se utilizaron dos grupos de hembras por línea: sin y con estimulación ovárica (5UI de eCG y 5UI de hCG). Las hembras se sacrificaron a las 56-72 hs y a los 7 días postservicio y después de la primera parición. Se observaron los números de cuerpos lúteos (CL), embriones (E) y sitios de implantación (SI) y el tamaño de camada al nacimiento (TC). Se estimaron las pérdidas totales (PT) y las pérdidas de cuerpos lúteos (PCL), de embriones (PE) y de fetos (PF). Los promedios de CL, E, SI y TC variaron en el mismo sentido de la selección practicada y fueron significativamente mayores (P<0,05) para las hembras estimuladas, a excepción de TC. La línea s' tuvo un potencial reproductivo superior pero un mayor costo biológico (mayor PT y más tardía) cuando se la comparó con las otras líneas. La estimulación ovárica produjo menores eficiencias reproductivas totales para las tres líneas y pérdidas gestacionales mayores y más tardías, principalmente de SI. Las hembras de la línea no seleccionada (t), no estimuladas, con pesos intermedios, parieron un mayor número de crías, partiendo de un número intermedio de CL, E y SI, con una menor y más temprana mortalidad embrionaria, demostrando ser las más eficientes desde el punto de vista reproductivo y productivo.

The ovarian structure was modified as a consequence of weight selection in a pair of mouse lines selected for high (s') and low weight (s). Lines were founded from an unselected population of CF1 strain (t). The follicle diameter and the number of the ovarian follicles and the corpora lutea were higher in s' females, but they did not reach a larger litter size at birth, may be, by an increase in the gestational losses. In these lines, the co-effects of long-term weight selection and ovarian stimulation were tested to evaluate if they increased gestational losses. Two groups of females per line were employed: without and with ovarian stimulation (5UI of eCG and 5UI of hCG). Females were slaughtered at 56-72hs and at 7 days post-breeding and after first parturition. The number of corpora lutea (CL), embryos (E) and implantation sites (SI), and litter size at birth (TC) were observed. Total losses (PT) and corpora lutea (PCL), embryo (PE) and fetus (PF) losses were estimated. Mean CL, E, SI and TC varied in the same direction of the selection made and they were significantly higher (P<0.05) in stimulated females, though not for TC. Line s' had a higher reproductive potential but a greater biological cost (higher and later gestational mortality) when compared with the other lines. Ovarian stimulation produced lower total reproductive efficiencies for the three lines and higher and later gestational losses, mainly for implantation sites. Females from unselected line (t), without ovarian stimulation, with intermediate weights, bore larger litters, starting from an intermediate number of CL, E and SI, with a lower and earlier embryo mortality, showing to be the most efficient from a reproductive and productive point of view.

Correlación entre embriocardia, saco vitelino y cuerpo lúteo en embarazo menor de diez semanas para eveluar su viabilidad y evolución

Existen reportes en la literatura mundial que, considerando algunos parámetros de ecografía temprana, hacen predicciones sobre le evolución del embarazo. Se pretendió demostrar estos hallazgos reportados universalmente para su aplicabilidad a la población que consulta al Hospital Militar Central, para la cual se realizaron ecografías transvaginales a 220 pacientes con embarazos menores de 10 semanas, en la Unidad de Ecografía Ginecoobstétrica del Hospital Militar Central o en la Unidad de Diagnóstico obstétrico y Ginecológico, (Obgyn), midiendo el diámetro del saco vitelino, cuantificando la embriocardia y valorando la presencia de cuerpo lúteo. Se realizó el seguimiento de las pacientes al final del período de estudio. Fueron excluidas 56 pacientes y con las 164 restantes no fue posible corroborar lo reportado en la bibliografía. Por tal motivo no podemos hacer ninguna predicción sobre el pronóstico del embarazo basados en las mediciones de ciertos parámetros por ecografía transvaginal en embarazos tempranos

Desenvolvimento de pré-embriöes de ratas Wistar da Colônia do Biotério do Centro de Biologia da Reproduçäo - UFJF / Pre-embryo development of Wistar rats from the Colony of Centro de Biologia da Reproduçäo Vivarium - UFJF

Durante a fase pré-embrionária, o concepto fica exposto às secreçöes tubárias que podem conter produtos tóxicos aos quais a mäe pode ter sido exposta no início do período gestacional. A determinaçäo dos padröes referentes ao número de pré-embriöes e suas diferentes fases do desenvolvimento é importante para a pesquisa de agentes com potencial tóxico. Neste trabalho estabeleceu-se a padronizaçäo do desenvolvimento dos pré-embriöes na fase de 2, 3 e 4 células, mórula e blastocisto, de ratas Wistar da colônia do Biotério do Centro de Biologia da Reproduçäo - UFJF.