Construcción de indicadores de biodiversidad funcional para estimar la presencia y actividad de murciélagos en agroecosistemas de la Pampa Ondulada

The loss of biodiversity in modern agriculture has resulted in the weakening of associated ecosystem services and an increase in the use of chemical inputs. Agroecology pointed out that it is possible to design and manage sustainable agroecosystems that minimize or eliminate the use of chemical inputs. One of them is the control by natural enemies such as bats. Their presence and activity may have an important place in strategies to strengthen the Biotic Regulatory Potential (PRB). PRB can be defined as the potential capacity of an agroecosystem to keep pest populations regulated through their ecological functions. In the province of Buenos Aires, bats are exclusively insectivores, and they play a fundamental role in natural areas as regulators of insect populations. Evaluating the capacity of a system to favor its presence and activity requires the development of simple indicators that can be applied on farms. Indicators were constructed based on a) the structure of the system and b) the management of the farmers. Its usefulness was tested in three farms located in the Rolling Pampa (Buenos Aires). The diversity and abundance of the captured bats coincided with the values ​​of the indicators, confirming that are good estimators of the presence and activity of bats. This allows the development of management strategies that favor bats as biological controllers.  La pérdida de biodiversidad en la agricultura moderna ha traído como consecuencia el debilitamiento de los servicios ecosistémicos asociados y el aumento del uso de insumos químicos. La agroecología señala que es posible diseñar y manejar agroecosistemas sustentables que minimicen o eliminen el uso de insumos químicos. Uno de ellos es el control por enemigos naturales como, por ejemplo, a través de los murciélagos. Su presencia y actividad pueden tener un lugar importante en las estrategias en el fortalecimiento del Potencial de Regulación Biótica (PRB). El PRB puede definirse como la capacidad potencial de un agroecosistema para mantener reguladas las poblaciones de plagas a través de sus funciones ecológicas. En la provincia de Buenos Aires los murciélagos son exclusivamente insectívoros, y juegan un papel fundamental en áreas naturales como reguladores de las poblaciones de insectos. Evaluar la capacidad de un sistema para favorecer su presencia y actividad requiere del desarrollo de indicadores sencillos que puedan ser aplicados en fincas. Se construyeron indicadores basados en a) la estructura del sistema y b) el manejo de los productores; y se comprobó su utilidad en tres fincas ubicadas en la Pampa Ondulada (Buenos Aires). La diversidad y abundancia de los murciélagos capturados coincidieron con los valores de los indicadores, señalando que estos últimos resultan ser buenos estimadores de las condiciones necesarias para su presencia y actividad. Esto permite desarrollar estrategias de manejo que favorezcan a los murciélagos como controladores biológicos

Pituitary expression of LH beta- and FSH beta-subunit mRNA, cellular distribution of LH beta-subunit mRNA and LH and FSH synthesis during and after treatment with a gonadotrophin-releasing hormone agonist in heifers

The aim was to examine transcriptional and post-transcriptional regulation of LH and FSH biosynthesis. Female cattle were allocated to three groups: (i) Group 1, control (n = 6), synchronized to be at around Day 11 of the oestrous cycle on Day 31; (ii) Group 2 (n = 6), treated with gonadotrophin-releasing hormone ( GnRH) agonist ( deslorelin) for 31 days; and ( iii) Group 3 ( n = 6), treated with deslorelin for 28 days. All animals were slaughtered on Day 31. For animals in Group 2, pituitary content of LHbeta-subunit mRNA was suppressed 60% (P 0.05) and FSH 90% ( P 0.05) whereas FSH remained reduced by 80%( P < 0.001). The ratio of LHβ-subunit mRNA present in the nucleus versus cytoplasm of gonadotroph cells was reduced ( P < 0.05) in heifers during treatment with deslorelin (0.59 +/- 0.05) compared with the ratio in control heifers (1.31 +/- 0.22) and heifers 3 days after discontinuation of treatment (1.01 +/- 0.05). The findings indicated that treatment with GnRH agonist can suppress LHbeta-subunit mRNA expression without any significant effect on FSHbeta-subunit mRNA. As LH and FSH contents were suppressed to a greater degree than their beta-subunit mRNAs, it would appear that treatment with a GnRH agonist might influence gonadotrophin biosynthesis by a post-transcriptional mechanism(s). For LHbeta-subunit mRNA, this would appear not to be reduced export of message from the nucleus

Construcción de indicadores de biodiversidad funcional para estimar la presencia y actividad de murciélagos en agroecosistemas de la Pampa Ondulada

La pérdida de biodiversidad en la agricultura moderna ha traído como consecuencia el debilitamiento de los servicios ecosistémicos asociados y el aumento del uso de insumos químicos. La agroecología señala que es posible diseñar y manejar agroecosistemas sustentables que minimicen o eliminen el uso de insumos químicos. Uno de ellos es el control por enemigos naturales como, por ejemplo, a través de los murciélagos. Su presencia y actividad pueden tener un lugar importante en las estrategias en el fortalecimiento del Potencial de Regulación Biótica (PRB). El PRB puede definirse como la capacidad potencial de un agroecosistema para mantener reguladas las poblaciones de plagas a través de sus funciones ecológicas. En la provincia de Buenos Aires los murciélagos son exclusivamente insectívoros, y juegan un papel fundamental en áreas naturales como reguladores de las poblaciones de insectos. Evaluar la capacidad de un sistema para favorecer su presencia y actividad requiere del desarrollo de indicadores sencillos que puedan ser aplicados en fincas. Se construyeron indicadores basados en a) la estructura del sistema y b) el manejo de los productores; y se comprobó su utilidad en tres fincas ubicadas en la Pampa Ondulada (Buenos Aires). La diversidad y abundancia de los murciélagos capturados coincidieron con los valores de los indicadores, señalando que estos últimos resultan ser buenos estimadores de las condiciones necesarias para su presencia y actividad. Esto permite desarrollar estrategias de manejo que favorezcan a los murciélagos como controladores biológicos

Construcción de indicadores de biodiversidad funcional para estimar la presencia y actividad de murciélagos en agroecosistemas de la Pampa Ondulada

The loss of biodiversity in modern agriculture has resulted in the weakening of associated ecosystem services and an increase in the use of chemical inputs. Agroecology pointed out that it is possible todesign and manage sustainable agroecosystems that minimize or eliminate the use of chemical inputs. One of them is the control by natural enemies such as bats. Their presence and activity may have an important place in strategies to strengthen the Biotic Regulatory Potential (PRB). PRB can be defined as the potential capacity of an agroecosystem to keep pest populations regulated through their ecological functions. In the province of Buenos Aires, bats are exclusively insectivores, and they play a fundamental role in natural areas as regulators of insect populations. Evaluating the capacity of a system to favor its presence and activity requires the development of simple indicators that can be applied on farms. Indicators were constructed based on a) the structure of the system and b) the management of the farmers. Its usefulness was tested in three farms located in the Rolling Pampa (Buenos Aires). The diversity and abundance of the captured bats coincided with the values of the indicators, confirming that are good estimators of the presence and activity of bats. This allows the development of management strategies that favor bats as biological controllers.La pérdida de biodiversidad en la agricultura moderna ha traído como consecuencia el debilitamiento de los servicios ecosistémicos asociados y el aumento del uso de insumos químicos. La agroecología señala que es posible diseñar y manejar agroecosistemas sustentables que minimicen o eliminen el uso de insumos químicos. Uno de ellos es el control por enemigos naturales como, por ejemplo, a través de los murciélagos. Su presencia y actividad pueden tener un lugar importante en las estrategias en el fortalecimiento del Potencial de Regulación Biótica (PRB). El PRB puede definirse como la capacidad potencial de un agroecosistema para mantener reguladas las poblaciones de plagas a través de sus funciones ecológicas. En la provincia de Buenos Aires los murciélagos son exclusivamente insectívoros, y juegan un papel fundamental en áreas naturales como reguladores de las poblaciones de insectos. Evaluar la capacidad de un sistema para favorecer su presencia y actividad requiere del desarrollo de indicadores sencillos que puedan ser aplicados en fincas. Se construyeron indicadores basados en a) la estructura del sistema y b) el manejo de los productores; y se comprobó su utilidad en tres fincas ubicadas en la Pampa Ondulada (Buenos Aires). La diversidad y abundancia de los murciélagos capturados coincidieron con los valores de los indicadores, señalando que estos últimos resultan ser buenos estimadores de las condiciones necesarias para su presencia y actividad. Esto permite desarrollar estrategias de manejo que favorezcan a los murciélagos como controladores biológicos

Studies of the pathogenesis of bovine pestivirus-induced ovarian dysfunction in superovulated dairy cattle

Two experiments (Experiment 1, n = 12 Holstein-Friesian heifers; Experiment 11, n = 8 Jersey cows) were conducted to investigate the pathogenesis of bovine pestivirus-induced ovarian dysfunction in cattle. In both experiments the cattle were superovulated with twice daily injections of, a porcine pituitary extract preparation of follicle stimulating hormone (FSH-P), for 4 days commencing on Day 10 +/- 2 after a presynchronised oestrus. The heifers received a total dose of 30 mg and the cows 32 mg of FSH-P. Prostaglandin F-2alpha. (PGF(2alpha)) was administered 48 h after commencement of superovulation and all cattle were artificially inseminated (AI) between 48 and 66 h after PGF(2alpha) treatment. In both experiments bovine pestivirus seronegative cattle (Experiment I, n = 6; Experiment 11, n = 4) were inoculated intranasally with an Australian strain of non-cytopathogenic bovine pestivirus (bovine viral diarrhoea virus Type 1) 9 days prior to AI. Bovine pestivirus infection was confirmed by seroconversion and/or virus isolation in all of the inoculated cattle, consistent with a viremia occurring approximately between Day 5 prior to AI and the day of AI. Ovarian function was monitored in both experiments by daily transrectal ultrasonography and strategic blood sampling to determine progesterone, oestradiol-17beta, luteinising hormone (LH) and cortisol profiles. Non-surgical ova/embryo recovery was performed on Day 7 after AI. In Experiment 11 half the cattle were slaughtered on Day 2 and the remainder on Day 8 after Al, and the ovaries submitted for gross and histopathological examination including immunohistochemistry to demonstrate the presence of bovine pestivirus antigen. In both studies, comparisons were made between infected and confirmed uninfected (control) animals. Overall the bovine pestivirus infected cattle had significantly lower (P < 0.05) ova/embryo recovery rates compared to the control cattle. There was evidence of either an absence (partial or complete) of a preovulatory LH surge or delay in timing of the LH peak in the majority (90%) of infected heifers and cows, and histologically, there was evidence of non-suppurative oophoritis with necrosis of granulosa cells and the oocyte in follicles from the infected cows. By contrast only 20% of the control heifers and cows had evidence of absence of a preovulatory LH surge. These experiments collectively demonstrate that bovine pestivirus infection during the period of final growth of preovulatory follicles may result in varying degrees of necrosis of the granulosa cells with subsequent negative effects on oestradiol-17beta secretion which in turn negatively affects the magnitude and/or timing of the preovulatory LH surge. (C) 2002 Elsevier Science Inc. All rights reserved