Abstract Introduction The evaluation of stroke volume (SV) is useful in research and patient care. To accomplish this, an ideal device should be noninvasive, continuous, reliable, and reproducible. The Mobil-O-Graph (MOG) is a noninvasive oscillometric matrix validated for measuring aortic and peripheral blood pressure, which through conversion algorithms can estimate hemodynamic parameters. Objectives To compare the MOG measurement of stroke volume, cardiac output, and cardiac index with the transthoracic echocardiogram (TTE). Methods Healthy volunteers aged 18 years or older were included. Two-dimensional TTEs were performed by a single operator. Subsequently, the measurement of noninvasive hemodynamics with MOG was performed with the operator blind to the results of the echocardiogram. Correlation analyses between stroke volume, cardiac output, and cardiac index parameters were performed. The degree of agreement between the methods was verified using the Bland-Altman method. Results A total of 38 volunteers were enrolled with a mean age of 27.6 ± 3.8 years; 21 (55%) were male The SV by TTE was 76.8 ± 19.5 mL and 75.7 ± 19.3 mL by MOG, Rho = 0.726, p< 0.0001. The CO by TTE was 5.04 ± 0.8 mL.min-1 and 5.1 ± 0.8 mL.min-1 by MOG Rho = 0.510, p= 0.001. Bland-Altman plots showed a good concordance between the two techniques. Conclusions Our study shows that the measurement of SV and CO by noninvasive hemodynamics with the MOG device offers a good concordance with the TTE with very few values beyond the confidence limits.

Resumen El estudio analizó, en dos años, los efectos de raza [Brahman (BHM; n= 65); Suizo Europeo (SE; n= 56)], suplementación con Zilpaterol® (ZIL; tratadas o testigo), estación de nacimiento (primavera u otoño) y sus interacciones, sobre superficie corporal (SC), edad (EPB), peso corporal (PPB), condición corporal (CC), profundidad del músculo largo dorsal (MD), grosor de grasa dorsal (GD) y concentración sérica de leptina (LEP) a la pubertad (PB) de 121 vaquillas. A la PB, las BHM fueron más pesadas y tuvieron más edad que las SE (376.8 ± 7.4 vs 302.0 ± 6.6 kg; 588.1 ± 14.7 vs 445.5 ± 12.5 días). ZIL aumentó EPB, PPB, CC y MD, pero no afectó GD y LEP. Las BHM tuvieron 18 % más SC que las SE. Sin embargo, la diferencia en PPB/SC fue sólo de 6.4 %. Cuando se usó peso metabólico (PM) como proporción de la SC (PM/SC) en lugar de PPB, la diferencia entre BHM y SE desapareció (P>0.05). El GD fue 63.7 % mayor en BHM que en SE. Las nacidas en primavera iniciaron la PB con 24.4 % menos GD que las nacidas en otoño. La mayoría de las vaquillas BHM (73.8 %) inició la PB en los meses en que las horas luz iban en aumento (P<0.05), mientras que en las SE el inicio de la PB estuvo uniformemente distribuido a través del año, independientemente de la duración de las horas luz; este efecto se mostró en los dos años de estudio. Se concluye que el establecimiento de la pubertad es un fenómeno multifactorial; la estacionalidad afecta a BHM y SE de manera diferenciada y, aparentemente, la SC es un factor importante, probablemente asociado con la eficiencia en la utilización de energía. Este trabajo reitera la importancia de la grasa dorsal y documenta, por primera vez PM/SC y su asociación con el establecimiento de la pubertad.

Abstract The study analyzed, in two years, the effects of breed [Brahman (BHM; n= 65); Braunvieh (BR; n= 56)], supplementation with Zilpaterol® (ZIL; treated or control), season of birth (spring or autumn) and their interactions on body surface (BS), age (APB), body weight (WPB), body condition (BC), long dorsal muscle (DM) depth, dorsal fat (DF) thickness and serum leptin concentration (LEP) at puberty (PB) of 121 heifers. At PB, BMHs were heavier and older than BRs (376.8 ± 7.4 vs 302.0 ± 6.6 kg; 588.1 ± 14.7 vs 445.5 ± 12.5 days). ZIL increased APB, WPB, BC and DM, but did not affect DF and LEP. BHMs had 18 % more BS than BRs. However, the difference in WPB/BS was only 6.4 %. When metabolic weight (MW) was used as a proportion of BS (MW/BS) instead of WPB, the difference between BHM and BR disappeared (P>0.05). The DF was 63.7 % higher in BHM than in BR. Those born in spring started PB with 24.4 % less DF than those born in autumn. Most of the BHM heifers (73.8 %) started PB in the months when light hours were increasing (P<0.05), while in BRs, the beginning of PB was uniformly distributed throughout the year, regardless of the length of light hours; this effect was present in the two years of study. It is concluded that the establishment of puberty is a multifactorial phenomenon; seasonality affects BHM and BR differently and, apparently, BS is an important factor, probably associated with efficiency in energy use. This paper reiterates the importance of dorsal fat and documents, for the first time, MW/BS and its association with the establishment of puberty.

Neurological manifestations such as seizures, disorders of consciousness and abnormal movements such as hemichorea and hemiballismus can be the presenting symptoms of hyperglycemic hyperosmolar states. Exceptionally, focal signs as hemiparesis or aphasia are described. We report a 66-year-old man, presenting with nonfluent aphasia and right subtle hemiparesis. The computed tomography, computed tomography angiography and brain magnetic resonance did not show acute ischemic lesions or obstruction of arterial vessels. The initial laboratory evaluation disclosed a blood glucose of 936 mg/dL, a plasma osmolality of 331 mOsm/Kg, and positive plasma ketones. After the treatment of hyperglycemia and hyperosmolality, focal symptoms subsided.

Abstract Canine overpopulation continues to be a problem with serious public health implications, despite a diversity of programs and strategies that have been implemented for its control. Coumestrol (COU) is an organic compound with estrogenic activity, thus having the potential to alter reproduction in mammals. COU is commonly dissolved in dimethyl sulfoxide (DMSO) before administration; however, evidence indicates that DMSO is not inert. The aim of this study was to assess the effects of either a single oral administration of COU diluted in DMSO or of DMSO-alone, on serum progesterone (P4) and estradiol (E2), on vaginal cell pattern, and on anestrus and diestrus lengths in bitches. Fifteen anestrus female dogs received either a single commercial dog food biscuit (Control, n=5), a biscuit with 600 µg of COU/kg diluted in 20 µL of DMSO (COU, n=5), or a biscuit with 20 µL of DMSO (DMSO, n=5). Circulating P4, E2, and changes in vaginal cytology, were assessed within the first month after treatment administration. Hormone levels were also measured from months 2-6 post-treatment. Mean differences were analyzed by the GLM procedure for repeated measures. COU enhanced serum E2 levels, and DMSO increased serum P4, number of vaginal anucleated superficial cells, and diestrus length. All dogs were deemed healthy based on all periodical clinical exams, but abnormal mammary gland growth and/or galactorrhea were observed in two COU and one DMSO-treated bitches. The findings of the present study expose the need to reevaluate previous reports of use of COU in bitches, and perhaps in other mammals.

Abstract: In prepubertal heifers, kisspeptin-10 (KISS-10) stimulates the release of the luteinizing hormone (LH) and the follicle-stimulating hormone (FSH) but the growth hormone (GH) response is inconsistent. The hypothesis of this study was that in prepubertal heifers, the release of LH, FSH and GH in response to KISS-10 is determined by dose and by endogenous levels of IGF-I and leptin. Twenty heifer calves (100-232 kg of body weight and 7-11 mo of age) received an i.v. injection of 5 or 50 µg of KISS-10/kg of body weight (low and high dose, respectively). The high dose of KISS-10 induced a greater (P<0.05) response of LH (area under the curve) and FSH (duration) than the low dose. IGF-I was negatively associated (P<0.05) to LH in response to the high dose of KISS-10 but IGF-I was not associated with LH in calves treated with the low dose (P>0.05). The magnitude of FSH response as well as GH serum concentrations after KISS-10 were not altered by IGF-I levels (P>0.05). Similarly, leptin concentrations were not associated (P>0.05) with the magnitude of LH and FSH response or GH concentrations after KISS-10. In conclusion, GH did not respond to any dose of KISS-10 but FSH and LH were sensitive to an increment in the KISS-10 dose. Additionally, the magnitude of response of LH to KISS-10 was determined by endogenous levels of IGF-I but it was not associated with levels of leptin.

Resumen: En becerras prepúberes, la kisspeptina-10 (KISS-10) estimula la liberación de hormona luteinizante (LH) y hormona foliculoestimulante (FSH), pero su acción en la hormona del crecimiento (GH) es inconsistente. La hipótesis fue que en becerras prepúberes la magnitud de liberación de LH, FSH y GH en respuesta a KISS-10 es determinada por la dosis y las concentraciones endógenas de IGF-I y leptina. Se usaron 20 becerras prepúberes (100-232 kg de peso y 7-11 meses de edad), mismas que recibieron un bolo i.v. de 5 o 50 µg de KISS-10/kg de peso. Ambas dosis de KISS-10 indujeron un incremento de LH y FSH, más no de GH. La dosis de 50 µg de KISS-10 indujo un área bajo la curva de LH y una duración del incremento de FSH mayores (P<0.05) que la dosis de 5 µg. IGF-I se relacionó negativamente con el aumento de LH en respuesta a la dosis de 50 µg (P<0.05), pero no estuvo asociado con la respuesta de LH a la dosis de 5 µg de KISS-10. La magnitud del incremento de FSH y las concentraciones de GH posteriores a KISS-10 no fueron alteradas por las concentraciones de IGF-I (P>0.05). De la misma forma, las concentraciones de leptina no determinaron (P>0.05) la magnitud del incremento de LH y FSH ni las concentraciones de GH pos tratamiento. En conclusión, la GH no respondió a ninguna dosis, pero la FSH y la LH fueron sensibles al aumento de dosis de KISS-10. Además, la magnitud de respuesta de LH a KISS-10 fue determinada por las concentraciones endógenas de IGF-I, pero no de leptina.

ABSTRACT Objectives: To determine the frequency of folic acid deficiency in consecutive serum folate determinations and to determine whether there was a significant decrease in serum folate deficiency after folate was added to wheat flour. Methods: A retrospective descriptive observational study was performed of consecutive folate measurements at the Hospital Privado Universitario, Cordoba, Argentina. Results: Two cohorts were analyzed: 1197 folate measurements between 2001 and 2008 (before supplementation) and 3335 folate measurements from 2009 to 2014 (after supplementation). Folate deficiency was found in 84/1197 (7%) subjects in the pre-supplementation group and in 58/3335 (1.73%) after supplementation. The prevalence of folate deficiency was 12% between 2001 and 2003 when folate was not added to flour compared to 4% in 2004-2007 (p-value < 0.0001) when folate was added to the flour but no widespread use was documented. Conclusions: In the studied population, the prevalence of serum folic acid deficiency after folate supplementation was low at 1.73%. There was a significant decrease in folate deficiency after folate was added to wheat flour. Given the low prevalence of folic acid deficiency observed in this and similar studies, and the observed change with supplementation, we conclude that routine measurement of serum folate is of limited clinical use.

Cut-off lows are closed cyclonic circulations that develop in high levels of the troposphere, separated from the westerly flow. They usually are associated with deep tropopause descent, allowing stratospheric air intrusions to the troposphere, which can lead to risks for the population, such as increments in surface ozone concentrations, increases of potential instability or generation of clear air turbulence. There is a preferential zone for the development of these systems west of SouthAmerica, over the Pacific Ocean, and for this reason the goal of this paper is to progress towards understanding the behavior of the tropopause in cut-off lows that affect the south of this continent. The dynamic definition of the tropopause, based on the discontinuity in the vertical of potential vorticity was used. The tropopause was identified with three different values of this quantity: -1.6, -2 and -3 PVU. 81 cases of cut-off lows that develop west of the Andes between 1998 and 2008 were analyzed, and the tropopause drop could be quantified in each one of them. The dynamic tropopauses of the studied cut-off lows showed drops with maximum values between 650 hPa and 550 hPa, depending of the potential vorticity value selected. The position of the maximum fall, relative to the center of the systems, was also analyzed, finding a dominant preference for the equatorial sector of the cut-off lows.

Las bajas segregadas son circulaciones ciclónicas cerradas que se desarrollan en niveles altos de la tropósfera, quedando separadas del flujo de los oestes. En general se asocian a profundas caídas de la tropopausa, permitiendo intrusiones de aire estratosférico en la tropósfera, lo que puede dar lugar a diversos riesgos para la población, tales como aumentos en las concentraciones de ozono en superficie, incrementos de la inestabilidad potencial o la generación de turbulencia en aire claro. La región del Océano Pacífico al oeste de Sudamérica es una zona preferencial para el desarrollo de estos sistemas, y por tal motivo se planteó como objetivo avanzar hacia la comprensión del comportamiento de la tropopausa en bajas segregadas que afectan el sur de este continente. Se utilizó la definición dinámica de la tropopausa, basada en la discontinuidad en la vertical de la vorticidad potencial. La tropopausa se identificó con tres valores distintos de esta cantidad: -1.6, -2 y -3 PVU. Se analizaron 81 casos de bajas segregadas que se formaron al oeste de los Andes entre 1999 y 2008 y se pudo cuantificar la caída de la tropopausa dinámica en cada una de ellas. La tropopausa dinámica de las bajas segregadas estudiadas mostró caídas con valores máximos de entre 650 hPa y 550 hPa, dependiendo del valor de vorticidad potencial utilizado. Se analizó también la posición de la máxima caída de la tropopausa dinámica relativa al centro de los sistemas, encontrando una preferencia dominante por el sector ecuatorial de las bajas segregadas.

ABSTRACT: To evaluate effects of age on the response of LH, FSH and GH to kisspeptin-10 (KISS) in prepubertal heifers and its association with circulating levels of IGF-I, estradiol (E2) and leptin, 21 heifer calves that were 4, 7 or 11 mo old, received an iv injection of KISS (5 μg/kg). LH, FSH and GH were quantified in blood serum taken every 15 min (4 h pre- and 4 h post-KISS-10). In three pre- and six post-KISS samples, IGF-I, leptin and E2 were determined. All heifers responded to KISS with an LH increment but the response magnitude differed among groups since maximum value was higher (P<0.05) in 11 mo (11.6+1.3 ng/ml) than in 7 mo (7.2±1.3 ng/ml) and 4 mo (6.1±1.3 ng/ml) old calves. Duration of response differed (P<0.05) among ages (11 mo=132.9+20 mina; 7 mo=92±20 mina,b; 4 mo=64.3±20 minb). For FSH, all and 11 mo calves responded to KISS but only 71.4 % of 4 mo did. In GH, 71.4 % of 4 mo and 85.7 % of 7 mo calves responded to KISS whereas 100 % of 11 mo animals responded. FSH and GH did not differ among age groups. The 11 mo heifers had the highest IGF-I and E2 but the lowest leptin levels. In conclusion, KISS evokes LH increments in all calves 4 to 11 mo old, but the response increases with age in association with high circulating IGF-I and E2 and low leptin. The response of FSH and GH to KISS is not influenced by age or variations in circulating IGF-I, E2 or leptin.

RESUMEN: El objetivo fue evaluar la respuesta de LH, FSH y GH a kisspeptina-10 (KISS) en becerras prepúberes de distintas edades, y su asociación con IGF-I, E2 y leptina circulantes. A 21 becerras de 4, 7 y 11 meses de edad se les aplicó una inyección i.v. de 5 µg de KISS/kg de peso. En suero obtenido de la yugular (cada 15 min, 4 h pre hasta 4 h post-KISS) se cuantificó LH, FSH y GH. En nueve muestras (tres pre y seis post-KISS) se determinó IGF-I, leptina y estradiol (E2). En todas las becerras aumentó la LH post-KISS, con un valor máximo (6.1±1.3a, 7.2±1.3a, 11.6+1.3b ng/ml) y duración de respuesta (64.3±20a, 92±20b, 132.9+20c min) que aumentó (P<0.05) con la edad. Para FSH, 71.4, 100 y 100 % de las becerras de 4, 7 y 11 meses respondieron a KISS-10; situación que para GH fue 71.4, 85.7 y 100 %, respectivamente. La magnitud de la respuesta de FSH y GH a KISS fue similar entre edades. Las becerras de 11 meses tuvieron las máximas concentraciones de IGF-I y E2 y las menores de leptina. Se concluye que KISS-10 evoca un aumento de LH en becerras de 4 a 11 meses, cuya magnitud de respuesta se asocia con la edad, con el incremento en sangre periférica de IGF-I y E2 y con la disminución de leptina sérica; en contraste, la respuesta de GH y FSH a KISS-10 no es afectada por la edad ni por las variaciones en IGF-I, E2 y leptina.

Both growth and milk production in heifer calves are stimulated by a long photoperiod, though this has not been proven yet in subtropical areas. To evalúate the effect of 16 hr of light (L16) on calves suckling (LAC) and/or pre-pubertal stages (PP) in a subtropical area, 325 calves (36 ± 0.4 kg) were randomized into two groups: L16 or natural photoperiod (LNAT). At seven months of age, 198 of these calves (195 ± 2 kg) were randomly assigned to L16 or LNAT. The following were determined at the beginning and end of LAC and PP stages: Weight (PC, kg), height (AC, cm), thickness of back-fat (GG, cm) and of Longissimus dorsi (LD, cm); pelvic area (AP, cm²), body condition (CC), age at first estrus, mammary gland depth (PGM, cm) and width (AGM, cm). The statistical analysis was made using ANOVA for a 2 X 2 factorial arrangement. At the end of LAC, GG was lower and LD greater in L16 animals, while, at the end of PP, L16 heifer calves had a greater PC (260 ± 3 vs 250 ± 3), AP (166 ± 1.2 vs 153 ± 1.2), LD (3.18 ± 0.04 vs 2.90 ± 0.04), and AGM (2.41 ± 0.02 vs 2.21 ± 0.02), but a lower GG (0.114 ± 0.003 vs 0.139 ± 0.003) as compared to LNAT heifer calves. More L16 animals (67 %) presented estrus versus LNAT (38 %) and the age of the rst estrus was lower in L1 (278 ± 2 vs 288 ± 2 d). Consequently, exposure to L16 during LAC promotes lean growth while lean growth and a bigger pelvis and mammary gland are prompted during PP. Hence, it may be concluded that PP heifer calves exposed to L16 have a higher production potential and lower risk of dystocia than LNAT animals.

En vaquillas el fotoperiodo largo estimula el crecimiento y la producción láctea, pero esto no se ha probado en áreas subtropicales. Para evaluar el efecto de 16 h luz (L16) durante la lactancia (PW) y/o la etapa prepuberal (PP) en un área subtropical, 325 becerras (36 ± 0.4 kg) fueron distribuidas a: L16 ó fotoperiodo natural (LNAT). A los siete meses de edad, 198 de esas becerras (195 ± 2 kg) se asignaron aleatoriamente a L16 y LNAT. Al inicio y final de PW y PP se determinó: peso (PC, kg), altura (AC, cm), grosor de grasa dorsal (GG, cm) y del músculo Longissimus dorsi (LD, cm); área pélvica (AP, cm²), condición corporal (CC), edad al primer estro, profundidad (PGM, cm) y anchura (AGM, cm) de la glándula mamaria. El análisis estadístico fue por ANDEVA para arreglos factoriales 2X2. Al final de PW, GG fue menor y LD fue mayor en L16. Al nal de PP, las vaquillas L16 tuvieron más PC (260 ± 3 vs 250 ± 3), AP (166 ± 1.2 vs 153 ± 1.2), LD (3.18 ± 0.04 vs 2.90 ± 0.04) y AGM (2.41 ± 0.02 vs 2.21 ± 0.02), pero menos GG (0.114 ± 0.003 vs 0.139 ± 0.003) que las de LNAT. Más vaquillas L16 (67 %) presentaron estro que LNAT (38 %) y la edad al primer estro fue menor en L16 (278 ± 2 vs 288 ± 2 d). Consecuentemente, la exposición a L16 durante PW promueve crecimiento magro y durante PP induce crecimiento magro, mayor pelvis y glándula mamaria. Se concluye que vaquillas PP expuestas a L16 tienen mayor potencial productivo y menor riesgo de distocia que las LNAT.

We evaluated the effect of kisspeptin-10 (Kiss-10) administered repeatedly on the release of LH and ovarian activity in prepubertal heifers. We also assessed the association of serum IGF-1 and leptin with these effects. Fourteen Holstein or Brown Swiss by Zebu female calves (11.2 ± 0.2 mo old, 187.4 ± 6.3 kg) were randomly assigned to receive every 2 h for three days an i.v. application of Kiss-10 (Kisspeptin-10; 5 pg/kg of body weight, n= 7) or saline solution (control, n= 7). Blood was collected every 15 min for 0-6, 24-30 and 72-78 h, and every 2 h until 84 h. Each application of Kiss-10 was followed by an increase of LH whose magnitude (area under the curve) decreased (P<0.05) over time. Kiss-10 induced a preovulatory surge of LH and corpus luteum formation in 28.5 % of the calves. Ovulating calves had the highest (P<0.05) serum concentrations of 1Gf-1 and the lowest (P<0.05) leptin. During 63 post-treatment days, no changes were detected in follicular waves attributable to treatments (P>0.05) and heifers did not show cyclic ovarian activity. The conclusion is that Kiss-10 given repeatedly to prepubertal heifers is sufficient to evoke consistent increases of LH, to induce ovulation and luteal activity in animals with high IGF-1 and low leptin in peripheral blood but it is insufficient to establish regular estrous cyclicity.

Se evaluó el efecto de la kisspeptina-10 (Kiss-10), administrada repetidamente, sobre la liberación de LH y la actividad ovárica en becerras pre-púberes. Asimismo, se determinó la asociación de IGF-1 y leptina séricas con dichos efectos. Catorce (14) becerras Holstein o Suizo Pardo por Cebú (11.2±0.2 meses de edad; 187.4±6.3 kg de peso), se asignaron aleatoriamente para recibir cada dos horas, durante tres días una aplicación i.v. de Kiss-10 (Kisspeptina-10; 5 pg/kg de peso; n=7) o solución salina fisiológica (Testigo, n=7). Se colectó sangre cada 15 min de las 0-6, 24-30 y 72-78 h, y cada 2 h hasta las 84 h. Cada aplicación de Kiss-10 fue seguida de un incremento de LH, cuya magnitud (área bajo la curva) disminuyó (P<0.05) con el tiempo. La Kiss-10 indujo una oleada preovulatoria de LH y formación de cuerpo lúteo en 28.5 % de las becerras, mismas que presentaron las mayores (P<0.05) concentraciones séricas de IGF-1 y las menores (P<0.05) de leptina. Durante 63 días postratamiento no se detectaron cambios en las ondas foliculares atribuibles a Kiss-10 (P>0.05), y ninguna becerra manifestó actividad ovárica cíclica. Se concluye que la Kiss-10 administrada repetidamente a becerras pre-púberes es un estímulo suficiente para evocar incrementos consistentes de LH, para inducir la ovulación y actividad lútea en animales con concentraciones séricas elevadas de IGF-1 y bajas de leptina, pero no para inducir la ciclicidad estral.

The aim of this study was to evaluate the productivity and profitability of two commercial sources of progesterone therapy as part of a hormonal induction treatment in a heifer dual purpose herd. A second objective was to determine the productivity and profitability of a recombinant bovine somatotropin (ST) application during induced lactation. Forty four Holstein heifers x Zebu crosses were used. Four treatments and two control groups were evaluated. For economic analysis all components of total cost (TC) of the companies were considered, further there was a simulation which was designed for three natural lactations after the hormonal induction, based on two scenarios in which different body weights were considered as different periods. Artificial induction of lactation yielded a 100% success rate in the four groups of animals with no statistical differences between them (P > 0.05). The best cost-benefit ratio (CBR) was recorded by CIDR treatment without ST. Although the four treatments showed economic viability, those without ST had a better ratio (B / C) than those supplemented with ST. As for the net present value (NPV), the benefits updated showed that the profits were higher when ST was not applied and, mainly, in the CIDR treatment. The internal rate of return (IRR) reveals that most of the treatments have a yield above 20%.

Los objetivos del presente trabajo fueron: 1) evaluar la productividad y rentabilidad de dos fuentes comerciales de progesterona como integrantes de un tratamiento lactoinductor en vaquillas de reemplazo de un hato de doble propósito y 2) determinar la productividad y rentabilidad de la aplicación de somatotropina bovina recombinante (ST) durante la lactación inducida. Se usaron 44 novillonas producto de cruzas Holstein x Cebú. Se evaluaron cuatro tratamientos y se manejaron dos grupos testigo. Para el análisis económico se consideraron todos los componentes del costo total (CT) de las empresas, adicionalmente se realizó una simulación en la que se proyectó para tres lactaciones naturales posteriores a la lactoinducción, basadas en dos escenarios en los que se consideraron diferentes pesos corporales como diferentes periodos. En los cuatro grupos de animales lactoinducidos, el 100% de las vaquillas respondió al tratamiento sin diferencias estadísticas entre ellas (P > 0.05). La mejor relación beneficio-costos (RBC) la registró el tratamiento CIDR sin ST. Si bien los cuatro tratamientos presentaron viabilidad económica, los tratamientos sin ST presentaron mejor relación (beneficio/costo) que aquellos tratamientos que sí fueron complementados con ST. En cuanto al valor actual neto (VAN), los beneficios actualizados de todos los años muestran que las utilidades que generaron los tratamientos fueron superiores cuando no se aplicó ST y, principalmente, en el tratamiento con CIDR. La tasa interna de rentabilidad (TIR) revela que la mayoría de los tratamientos tienen una rentabilidad arriba del 20%.

Neste trabalho foram estudados os processos dinâmicos e termodinâmicos que envolvem o ciclo de vida de um caso de vórtice ciclônico desprendido em altos níveis, que ocorreu em março de 2007. Tais processos são analisados através dos termos das equações de vorticidade e termodinâmica usando um conjunto de análises geradas com o modelo BRAMS. Os principais processos que explicam o desprendimento da parte subtropical de um cavado são a advecção horizontal da vorticidade anticiclonica em níveis altos e a advecção horizontal de ar quente em níveis médios, ambas sobre o sul do Oceano Pacífico e estendendo-se em direção a região Patagônica, aprofundando a crista localizada corrente acima do cavado. A continuidade do aprofundamento desta crista, juntamente com a crista localizada corrente abaixo do cavado são as responsáveis da intensificação do sistema de baixa pressão. O efeito da divergência se opõe a advecção horizontal da vorticidade, e isso explica a situação estacionaria da baixa desprendida a barlavento da Cordilheira dos Andes. A fase de decaimento é dominada pela advecção vertical de ar quente. A análise das trajetórias das parcelas, considerando a conservação da vorticidade potencial, permitiu observar a entrada de ar estratosférico até os níveis médios da troposfera, em torno do vórtice ciclônico desprendido em altos níveis.

The dynamic and thermodynamic processes involved in the life cycle of a cutoff low occurred in March 2007 are studied. These processes are analyzed using the vorticity and thermodynamic equations and a set of analyses generated with the BRAMS model. The main processes that explain the segregation of the subtropical part of the trough are the horizontal advection of cyclonic vorticity at high levels and warm horizontal advection at middle levels, both over the Pacific Ocean extending south to the Patagonia region, building the ridge located upstream of the trough. Increased intensity of the upper level low pressure system is mainly explained by intensification of the ridges down and upstream. The divergence effect is opposed to the horizontal advection of vorticity which explains the stagnation of the cut-off low windward of the Andes. The decay stage is dominated by warm vertical advection. Assuming the conservation of potential vorticity the analysis of parcel trajectories , allowed detecting the entrance of stratospheric air to middle levels of the lower troposphere around the cut-off low.

This paper describes the life cycle of a high level cut-off cyclonic vortex that affected southern South America between 26 March and 2 April 2007, and explores the relationship between the evolution stages of the system and the rainfall over central Argentina. The possibility of other processes contributing to rainfall is also analyzed. The most relevant characteristics of this system were its length and slow displacement: from its development to decay it moved only 780 km. During its segregation and mature stages, it remained stationary for over 56 hours along the coast of central Chile. This latter feature favored the establishment of a low pressure system in the northwest of Argentina and the persistence of a northerly low level jet, from the center of Bolivia to the north of Argentina. The air mass with tropical characteristics driven by this system and the low-level convergence contributed to the development of convection. Accumulated rainfall during those stages, in some regions of central eastern Argentina was above 300 mm, producing significant flooding in the region. During the decay phase (96 hours duration), the system weakened as it moved eastward and precipitation affected the provinces of central-western Argentina, where the 48 h rain was twice the monthly average for March.

En este trabajo se analiza el ciclo de vida de una baja segregada que afectó el sur de Sudamérica entre el 26 de Marzo y el 2 de Abril del 2007 y se explora la relación existente entre las diferentes etapas de este sistema y la precipitación ocurrida sobre la franja central de Argentina. Además se evalúa si otros procesos coadyuvaron para la ocurrencia de la misma. Las características más relevantes de este sistema son su larga duración y el lento desplazamiento, ya que entre el inicio y el fin de su vida se desplaza sólo 780 km, manteniéndose estacionario, durante las etapas de segregación y madurez, por más de 56 hs frente a la costa central chilena. Esta última característica favorece la formación de un sistema de baja presión sobre el noroeste de Argentina y la persistencia de una corriente en chorro en capas bajas del norte que se extiende desde el centro de Bolivia hasta norte argentino. La masa de aire con características tropicales conducida por esta configuración y la convergencia en niveles bajos favorecieron el desarrollo convectivo. La precipitación acumulada durante estas etapas, en algunas regiones del sur del litoral argentino, superó los 300 mm, produciendo extensas inundaciones en la región. Durante la etapa de decaimiento (96 hs de duración), el sistema se debilita a medida que se desplaza hacia el este y las precipitaciones afectaron las provincias del centro-oeste de Argentina donde la lluvia en 48 horas duplicó el promedio mensual de marzo.

Se examinó el efecto de cero, una y tres inyecciones de naloxona (NX; 500 mg) el día 30 posparto a intervalos de 1 h, sobre la liberación de la hormona luteinizante (LH), en vacas de doble propósito en anestro: ¾ Europeo x ¼ Cebú (n = 18). Las vacas pastorearon en zacate Estrella de África (Cynodon plectostachyus) y gramas nativas (Axonopus y Paspalum spp.) con un consumo de 5 kg de alimento balaceado diariamente (16 % de PC). El ordeño fue mecánico dos veces al día y se realizó amamantamiento de las crías después del ordeño (30 min). Las vacas y las crías permanecieron separadas, excepto durante el amamantamiento. Se colectó una muestra de sangre cada 2 días desde el parto hasta el día 30 posparto y se cuantificó la progesterona (P) sérica por RIA. El anestro fue indicado por P < 1 ng/ml. El día 30 posparto se tomaron muestras de sangre cada 15 min durante 3 horas: una hora después de cada inyección de NX o solución salina fisiológica y se cuantificó la LH sérica por RIA. Las variables de respuesta fueron: concentración media (MLH) y basal (BLH), número (NP), amplitud (AP) y duración (DP) de pulsos de LH. Se usó un ANDEVA con parcelas divididas, parcela mayor = tratamiento y subparcela = período de muestreo. No hubo efectos (p >0.05) de tratamiento, período y sus interacciones en las variables de respuesta. En vacas de doble propósito con doble ordeño y amamantamiento, la naloxona no cambió la secreción de la LH en el día 30 posparto.

This study determined the effect of zero, one and three intramuscular injection of naloxone (NX, 500mg) on 30 postpartum day for 1 hour intervals over the release of the luteinizing hormone in dual purpose cows in anestrous (¾ Europe x ¼ Zebu) cows (n =18). The cows grazed on African Star grass (Cynodon plectostachyus) and native grass (Axonopus and Paspalum spp) and ate daily 5 kg of balanced food (16% crude protein). The cows were mechanically milked twice a day and after that their calves were allowed to suck for 30 minutes. A blood sample was collected every two days, from the delivery until 30 days postpartum for the quantification of progesterone (P) by RIA. In this blood anestrous was indicated by P< 1 ng/ml. On day 30 postpartum blood samples were drawn every 15 min during 3 hours: one hour after each naloxone injection or saline solution and Luteinising Hormone (LH) was measured by RIA. The response variables were mean (MLH) and basal concentration (BLH), number (PN), amplitude (PA) and pulse duration (PD) of LH. The statistic analysis was divided plot; principal plot was the treatment and secondary plot was the samples period. There were not effects (p>0.05) of treatment, samples period and its interactions on response variables. In double purpose cows with double milking and suckling naloxona did not affect the LH secretion at 30 day pospartum

El ciclo reproductivo anual de la oveja es regulado por la amplitud del fotoperiodo. La señal luminosa se traduce en una señal hormonal a través de la síntesis de melatonina. La disminución en la duración del fotoperiodo induce la actividad reproductiva y el aumento en las horas luz, inhibe la actividad ovulatoria estral, la conducta de estro y la ovulación (anestro estacional). Durante la época reproductiva, la progesterona (P4) regula los ciclos estrales de la oveja inhibiendo la secreción pulsátil de la hormona liberadora de gonadotropinas (GnRH) a nivel del área preóptica (POA) del hipotálamo, donde ejerce su acción de manera indirecta, posiblemente a través del ácido gama amino butírico (GABA) y los péptidos opioides endógenos (POEs). En la fase folicular del ciclo estral, el estradiol (E2) ejerce un efecto de retroalimentación positiva a nivel del hipotálamo mediobasal (HMB), incrementa la secreción pulsátil de GnRH y de la hormona luteinizante (LH), e induce el pico preovulatorio de ambas hormonas, provocando la conducta de estro y la ovulación. Durante la época de anestro estacional, el patrón de secreción de melatonina favorece el aumento en la sensibilidad del hipotálamo a la concentración basal de E2; este esteroide inhibe la secreción pulsátil de GnRH, actuando específicamente en el núcleo A15 dopaminérgico del área retroquiasmática lateral (Arch) hipotalámica. En este mecanismo, el sistema dopaminérgico participa como intermediario entre el E2 y las neuronas GnRH.

The annual reproductive cycle in the ewe is controlled by the changes in the amplitud of photoperiod. The light stimulus is converted into a hormonal signal: the circadian rhytm of melatonin secretion. Short days are inductive whereas long days inhibits the ovulatory activity. During the reproductive season, progesterone regulates the estrous cycle of the ewe inhibiting the GnRH pulsatil secretion. Progesterone exerts its action on the preoptic area of the hypothalamus indirectly, possibly via the gamma aminobutiric acid and the endogeneous opiod peptides. Estradiol (E2) increases the GnRH pulsatile secretion by a positive feedback effect. Increments in GnRH pulses induce the preovulatory peak of LH evoking estrous behaviour and ovulation. During the seasonal anestrus, the secretion pattern of melatonin increases the sensivity of the hypothalamus to the negative effect of E2, then estradiol inhibits the pulsatil secretion of GnRH, acting in the A-15 dopaminergic nucleous of the retrochiasmatic lateral area of the hypothalamus; in this mechanism the dopaminergic system mediates the effect of estradiol on the GnRHergic neurons.

O ciclo reprodutivo anual da ovelha é regulado pela amplitude do foto período. O sinal luminoso se traduz em um sinal hormonal a través da síntese de melatonina. A diminuição na duração do foto período induz a atividade reprodutiva e o aumento nas horas luz, inibe a atividade ou ciclo estral, a conduta de estro e a ovulação (anestro estacional). Durante a época reprodutiva, a progesterona (P4) regula os ciclos estrais da ovelha inibindo a secreção pulsátil do hormônio liberador de gonadotropinas (GnRH) a nível da área preóptica (POA) do hipotálamo, onde exerce sua ação de maneira indireta, possivelmente a través do ácido gama amino butírico (GABA) e os peptídeos opioides endógenos (POEs). Na fase folicular do ciclo estral, o estradiol (E2) exerce um efeito de retro alimentação positiva a nível do hipotálamo mediobasal (HMB), incrementa a secreção pulsátil de GnRH e do hormônio luteinizante (LH), e induz o pico pré ovulatório de ambos hormônios, provocando a conduta de estro e a ovulação. Durante a época de anestro estacional, o padrão se secreção de melatonina favorece o aumento na sensibilidade do hipotálamo à concentração basal de E2; este esteróide inibe a secreção pulsátil de GnRH, atuando especificamente no núcleo A15 dopaminérgico da área retroquiasmática lateral (Arch) hipotalâmica. Neste mecanismo, o sistema dopaminérgico participa como intermediário entre o E2 e os neurônios GnRH.