How pigs influence indoor air properties in intensive farming: Practical implications - A review

Indoor environmental conditions in intensive pig farms are influenced by both the outdoor air temperature and humidity, and the heat, moisture and gas exchanges between the animal and the air. As ventilation rate in pig facilities is usually estimated in temperature, moisture and even CO2 balances, estimation of heat losses or gains, and moisture and CO2 production from the animal is needed, but the contribution of other sources of the barn, such as slurry or wet surfaces have also to be taken into account. Some recent studies have been conducted to update total heat and moisture production at farm level, showing that current, historical standards of latent heat transfer are consistently lower than those reported recently at facility level, for both adult and growing animals. Also, CO2 production needs to be updated by including an estimation of its release from slurry. These new values will help with updating the standards for ventilation rate recommendations and design of the modern intensive pig buildings

Eclipsed X-ray flares in binary stars: geometrical constraints on the flare's location and size

The observation of eclipses during X-rays flares taking place in active cool stars binaries allows us to calculate the position and size of the flares. This information cannot be derived by analyzing the decay of the flares, a frequently used approach in the literature that requires the assumption of a physical model. We make use of the eclipsing light curve to constrain the set of possible solutions, from the geometrical point of view, in two flares of Algol, and one flare in VW Cep. We make use of a technique developed with the system SV Cam (i~90 deg) and generalize it to binary systems with arbitrary inclination. The method simulates all possible geometrical situations that can produce the times of the four contacts of the eclipse. As an approximation we assume that the emitting region has a spherical shape that remains unchanged during the eclipse. We however show that this is a good approximation for the problem. The solutions observed indicate that in two of the three cases the flare cannot be polar (lat<55 deg) and in a third one the flare can be placed either near the pole or at other latitudes. The emitting regions must have a small size (0.002-0.5 R_*), but if interpreted as the apex of coronal loops, their length could actually be up to 3.1 R_* for one of the Algol flares. These measurements imply a lower limit to the electron density in the emitting region between log n_e(cm^-3) 10.4 and 14.0, and a magnetic field between 70 and 3500 G. Similar results are found if the emitting region is assumed to be loop-shaped.Comment: 8 pages (17 in online version), 9 figures (18 in online version). Figure 12 is a set of animated GIF, available also at http://laeff.esa.es/users/jsanz/Papers/Eclipses/Videosweb . Accepted for publication in A&

Meta-analysis of the efficacy of melatonin implants for improving reproductive performance in sheep

To evaluate the efficacy of melatonin implants on increasing the production of lambs, a meta-analysis was performed based on the results of 139 experiments carried out in Spain and published in 56 scientific publications or conference proceedings. To assess the effects on fertility, the relative risk (RR) was calculated and, in the case of prolificacy and fecundity, the analysis was based on raw mean difference (D) and the standardized difference between means (d) and their corresponding confidence intervals. In addition, the experiments were stratified by the productive aptitude of the flocks, breed, time of year, and age. For fertility, the mean RR was 1.29, which indicated that the treatment with melatonin increased significantly (by 29%) the probability of pregnancy. For prolificacy, overall D was 0.08 (d = 0.9089); i.e., the groups treated with melatonin increased their litter size by 0.08 lambs/lambing relative to the control groups. Ultimately, treatment with melatonin increased fecundity significantly (0.25 extra lambs/ewe treated) (d = 6.3188), and this trend was evident in all of the stratified datasets. In all cases, there was significant (p < 0.001) heterogeneity and bias. In conclusion, in Spain, melatonin implants had a significant effect on the probability that a ewe became pregnant, increased the number of lambs born per lambing, which ultimately increased the number of lambs born per treated ewe. In addition to confirm the results of previous descriptive reviews in the scientific literature, the metaanalysis made use of a statistical tool that synthesizes and estimates more precisely the effect of this hormone on sheep reproduction. Se ha realizado un meta-análisis sobre la eficacia del uso de implantes de melatonina en ovino en España, analizando los resultados de 139 experiencias publicadas en 56 publicaciones o comunicaciones. Para la fertilidad se han calculado los riesgos relativos (RR) y para la prolificidad y fecundidad se han calculado la diferencia no estandarizada o bruta entre medias (D) y la diferencia estandarizada entre medias (d). Los resultados se han estratificado por aptitud productiva de los rebaños, raza, época del año y edad. Se han calculado los estadísticos de heterogeneidad y el posible sesgo entre publicaciones. Para la fertilidad, el RR medio fue 1,29, lo que significa que la melatonina incrementó de manera significativa las posibilidades de parto un 29%. Para la prolificidad, la D global fue 0,08 (d = 0,9089), es decir, los grupos tratados incrementaron su prolificidad 0,08 corderos/parto. El tratamiento con melatonina aumentó de manera significativa la fecundidad, con 0,25 corderos extra producidos/oveja tratada (d = 6,3188). En todos los casos, la heterogeneidad y el sesgo calculados fueron significativos (p < 0,001). En conclusión, el metaanálisis realizado ha revelado un efecto significativo de la melatonina en España sobre la posibilidad de que una oveja quede gestante, además de elevar el número de corderos nacidos por parto, lo que al final incrementa el número de corderos nacidos por oveja tratada. Esto no ha hecho sino confirmar lo revisado previamente en la literatura de manera narrativa, mediante una herramienta estadística, que sintetiza y estima de manera más precisa el efecto de esta hormona

Coronal versus photospheric abundances of stars with different activity levels

We report a detailed analysis of the coronal abundance of 4 stars with varying levels of activity and with accurately known photospheric abundances. The coronal abundance is determined here using a line flux analysis and a full determination of the differential emission measure. Photospheric abundance values are taken from literature works. Previous coronal abundance determinations have generally been compared to solar photospheric abundances; from this a number of general properties have been inferred, such as the presence of a coronal metal depletion with an inverse First Ionization Potential correlated with activity level. Here we show that, when coronal abundances are compared with real photospheric values for the individual stars, the resulting pattern can be very different. Also, we present evidence that, in some cases, the coronal metal abundance may not be uniform in the corona; in particular it can vary with the temperature of the emitting plasma.Comment: 10 pages, Online material: 8 pages (online material is included in the file). Accepted by A&

The flaring and quiescent components of the solar corona

The solar corona is a template to understand stellar activity. The Sun is a moderately active star, and its corona differs from active stars: active stellar coronae have a double-peaked EM(T) with the hot peak at 8-20 MK, while the non flaring solar corona has one peak at 1-2 MK. We study the average contribution of flares to the solar EM(T) to investigate indirectly the hypothesis that the hot peak of the EM(T) of active stellar coronae is due to a large number of unresolved solar-like flares, and to infer properties on the flare distribution from nano- to macro-flares. We measure the disk-integrated time-averaged emission measure, EM_F(T), of an unbiased sample of solar flares analyzing uninterrupted GOES/XRS light curves over time intervals of one month. We obtain the EM_Q(T) of quiescent corona for the same time intervals from the Yohkoh/SXT data. To investigate how EM_F(T) and EM_Q(T) vary with the solar cycle, we evaluate them at different phases of the cycle (from Dec. 1991 to Apr. 1998). Irrespective of the solar cycle phase, EM_F(T) appears like a peak of the distribution significantly larger than the values of EM_Q(T) for T~5-10 MK. As a result the time-averaged EM(T) of the whole solar corona is double-peaked, with the hot peak, due to time-averaged flares, located at temperature similar of that of active stars, but less enhanced. The EM_F(T) shape supports the hypothesis that the hot EM(T) peak of active coronae is due to unresolved solar-like flares. If this is the case, quiescent and flare components should follow different scaling laws for increasing stellar activity. In the assumption that the heating of the corona is entirely due to flares, from nano- to macro-flares, then either the flare distribution or the confined plasma response to flares, or both, are bimodal.Comment: 8 pages, 7 postscript figures, accepted for publication in Astronomy and Astrophysic

Efectos del uso de lonas térmicas de polipropileno en naves de destete durante el invierno

publishedTomo I . Sección: Sistemas Ganaderos-Economía y Gestión. Sesión: Conejos, abejas, peces y cerdos. Ponencia nº 2

La colaboración empresa-universidad en el ámbito de las razas ovinas autóctonas españolas: el ejemplo de Melovine

Se describe la colaboración establecida desde los años 90 hasta la actualidad entre un laboratorio veterinario (CEVA Salud Animal) y una universidad española (Universidad de Zaragoza), con la hormona pineal melatonina como eje. Los objetivos fundamentales han sido la descripción de los mecanismos básicos de actuación de esta hormona sobre la estacionalidad reproductiva de la especie ovina y la realización de pruebas de campo en ganaderías comerciales españolas, en un buen número de razas autóctonas, con el fin de difundir los resultados obtenidos en condiciones reales de explotación. Este hecho ha involucrado a todos los eslabones del sector ovino español, desde el laboratorio, el ganadero, la cooperativa, el veterinario, las asociaciones de defensa sanitaria, las administraciones públicas, las asociaciones de razas, coordinados todos ellos por un departamento universitario. Se ha trabajado con las razas autóctonas Castellana, Churra, Latxa, Manchega, Merina, Ojalada, Ojinegra, Rasa Aragonesa, Ripollesa y Segureña, además de otras como la Assaf y Lacaune. Se han descrito protocolos de uso de los implantes de melatonina en ovejas adultas, corderas y moruecos, en distintos momentos fisiológicos y sistemas de explotación. Todos ellos han sido difundidos al sector ovino español a través de publicaciones científicas y técnicas y a través de congresos, ponencias y cursos destinados a veterinarios y ganaderos

Expectativas previas y satisfacción del usuario en un programa de tratamiento de mantenimiento con metadona

Los indicadores de satisfacción miden el grado de conformidad con la atención recibida y se construyen en base a las apreciaciones subjetivas de los pacientes. Los factores que influyen en la percepción de los tratamientos con metadona son: la utilización del fármaco, las listas de espera y la influencia sobre aspectos laborales. Se plantea este estudio con los objetivos de conocer las expectativas de los pacientes, previas al inicio de un programa de tratamiento con metadona y estudiar el grado de satisfacción con el mismo. Se elaboró una entrevista estructurada de preguntas abiertas a cerca de la información y expectativas previas al tratamiento. También se elaboró un cuestionario relativo a la accesibilidad, a las características del programa y a la intervención del equipo. La satisfacción con el programa (88,35%) y con el equipo terapéutico (92,02%) fueron muy altas, no así con la accesibilidad al tratamiento (73.4%). Los desplazamientos a la unidad interferían negativamente en las obligaciones de casi la mitad de los pacientes. Se proponen mejoras orientadas a facilitar la accesibilidad al fármaco

Sheep as an experimental model: individual housing allowing visual, auditory, olfactory and tactile contact is not an obstacle for studies involving hormonal interrelationships

Thirty-two ewes were used to determine whether individual housing, allowing contact with neighbours, induces a stress response. Ewes were housed in individual pens designed to allow the ewes to see, hear, smell and touch adjacent animals, and were distributed into four groups (n=8/group): ewes with subcutaneous implants containing melatonin and oestradiol (M+E), melatonin (M), oestradiol (E) and non-implanted control ewes (C). Heart rate, stress indicators (plasma cortisol, glucose, lactate and creatine kinase (CK) concentrations) and luteinizing hormone (LH) concentrations were measured hourly and compared with the resting values (before and after pen housing). Heart rate increased significantly during the introduction into the pen (P<0.001) in all groups, in comparison with the resting values. No significant differences between groups were observed for cortisol concentrations, with the exception of the M group, which showed the highest response (P<0.001) when ewes were introduced into the pens. Lactate, CK and glucose changes in comparison with the resting values were similar between groups. LH concentrations during pen housing decreased significantly in all groups in comparison with resting values. In conclusion, individual confinement of sheep allowing visual, auditory, olfactory and tactile contact with their neighbouring animals was not an obstacle for investigating particular hormonal interrelationships with multiple sampling procedures. However further investigations are required to determine if this conclusion applies to other hormone systems in sheep