Study of the correlation between the magnetic and electrical properties of the La0.6Sr0.4MnO3 compound.

In this work, we investigated the relationship between the electrical and magnetic properties of the superparamagnetic (SPM) La0.6Sr0.4MnO3 (S1C0) compound prepared by the sol-gel method. The (S1C0) sample displayed a ferromagnetic metallic (FMM) behavior at low temperatures and a paramagnetic semiconductor (PMSC) behavior at high temperatures. The FMM behavior was described by the Zener Double Exchange (ZDE) polynomial law containing the contributions of the electron-electron (e-e) interactions and the electron-magnon (e-m) scattering. The PMSC behavior was described by the Mott Variable Range Hopping (Mott-VRH) transport model. The semiconductor/metallic transition temperature has been approximated at the blocking temperature. The Thermal Coefficient of Resistivity (TCR), which exhibits a linear variation around ambient temperature, can be used as a calibration curve for thermometry. Thus, our sample can be considered as a good candidate for the detection of infrared radiation used in night vision bolometer technologies.

Synthesis, characterization, and sensitivity tests of La0.8Ba0.1Bi0.1FeO3 nanoparticles towards a few parts-per-billion of acetone gas.

In the present paper, the La0.8Ba0.1Bi0.1FeO3 powders were synthesized via the auto-combustion method. The optical, the positron annihilation spectroscopy and the gas sensing properties of our sample were investigated simultaneously. FTIR spectrum revealed the antisymmetric deformation vibrations of the Fe-O and Fe-O-Fe bonds inside the octahedron FeO6. The optical bandgap (Egap) of the La0.8Ba0.1Bi0.1FeO3 compound was found to be equal to 2.23 eV. We confirmed by the positron annihilation studies, the existence of open volume defects and vacancy sized defects, at the grain/interfaces between vacancy clusters and grains at the interfaces intersection (triple-lines). Notably, the La0.8Ba0.1Bi0.1FeO3 perovskite exhibits an excellent response toward acetone gas, with ultra-fast response and recovery times to some parts-per-billion (ppb) of this tested gas.

Proyecto INCLIASMA fase II - Inercia clínica en asma en España / INCLIASMA phase II project – Clinical inertia in asthma in Spain

Objetivos El 80% de los pacientes con asma están mal controlados. A pesar de disponer de guías de práctica clínica (GPC) actualizadas, se sigue detectando un deficiente control y tratamiento del asma. El objetivo principal del estudio INCLIASMA faseII (INercia CLInica en ASMA) es analizar la realidad en el manejo del asma en las consultas de atención primaria (AP) españolas. Como objetivo secundario se planteó establecer una serie de recomendaciones clave en el manejo del paciente con asma, basadas en las conclusiones de los panelistas. Material y métodos Estudio transversal descriptivo, multicéntrico y no aleatorizado, que se desarrolló en dos rondas, siguiendo la metodología Delphi. Se elaboró un cuestionario on line específico para el proyecto de 41 ítems y divido en 5 bloques (diagnóstico, control, adherencia, tratamiento y criterios de derivación) y se pidió a un grupo de médicos de AP expertos en asma que expresaran su nivel de acuerdo o desacuerdo con el conjunto de ítems del cuestionario. De los resultados se identificaron las principales controversias existentes en el manejo de asma en España y se elaboraron recomendaciones prácticas. Resultados Participaron 24 panelistas. Hubo un consenso final en el 92,68% (38/41) de la totalidad de los ítems recogidos en el cuestionario. Los panelistas concluyeron que se tarda en exceso en diagnosticar el asma, existiendo un porcentaje elevado de pacientes asmáticos sin un correcto tratamiento, y, por ende, sin un adecuado control. La falta de tiempo, la sobrecarga asistencial o la inercia terapéutica son algunos de los factores determinantes de esta situación. Conclusione El estudio INCLIASMA faseII pone de relieve las controversias encontradas en la práctica clínica habitual en el manejo del asma, poniendo de manifiesto la necesidad continuada de formación y ofreciendo recomendaciones consensuadas que buscan mejorar el manejo de asma en nuestro país (AU)

Objectives Eighty percent of patients with asthma are poorly controlled. Despite the availability of updated clinical practice guidelines, poor asthma control and treatment continue to be detected. The main objective of the INCLIASMA phaseII study (INercia CLInica en ASMA) is to analyze the reality of asthma management in Spanish primary care (PC) clinics. As a secondary objective, it was proposed to establish a series of key recommendations in the management of patients with asthma, based on the conclusions of the panelists. Material and methods Cross-sectional descriptive, multicenter and non-randomized study, which was developed in two rounds, following the Delphi methodology. A specific online questionnaire was developed for the project with 41 items and divided into 5 blocks (diagnosis, control, adherence, treatment and referral criteria) and a group of PC physicians who were experts in asthma were asked to express their level of agreement or disagreement with the set of items in the questionnaire. From the results, the main existing controversies in the management of asthma in Spain were identified and practical recommendations were elaborated. Results Twenty-four panelists participated. There was a final consensus in 92.68% (38/41) of all the items collected in the questionnaire. The panelists concluded that it takes too long to diagnose asthma, and there is a high percentage of asthmatic patients without proper treatment, and therefore, without adequate control. Lack of time, care overload or therapeutic inertia are some of the determining factors in this situation. Conclusions The INCLIASMA phaseII study highlights the controversies found in routine clinical practice in asthma management, highlighting the continued need for training and offering consensus recommendations that seek to improve asthma management in our country (AU)

[INCLIASMA phase II project - Clinical inertia in asthma in Spain]. / Proyecto INCLIASMA fase II - Inercia clínica en asma en España.

OBJECTIVES: Eighty percent of patients with asthma are poorly controlled. Despite the availability of updated clinical practice guidelines, poor asthma control and treatment continue to be detected. The main objective of the INCLIASMA phaseII study (INercia CLInica en ASMA) is to analyze the reality of asthma management in Spanish primary care (PC) clinics. As a secondary objective, it was proposed to establish a series of key recommendations in the management of patients with asthma, based on the conclusions of the panelists. MATERIAL AND METHODS: Cross-sectional descriptive, multicenter and non-randomized study, which was developed in two rounds, following the Delphi methodology. A specific online questionnaire was developed for the project with 41 items and divided into 5 blocks (diagnosis, control, adherence, treatment and referral criteria) and a group of PC physicians who were experts in asthma were asked to express their level of agreement or disagreement with the set of items in the questionnaire. From the results, the main existing controversies in the management of asthma in Spain were identified and practical recommendations were elaborated. RESULTS: Twenty-four panelists participated. There was a final consensus in 92.68% (38/41) of all the items collected in the questionnaire. The panelists concluded that it takes too long to diagnose asthma, and there is a high percentage of asthmatic patients without proper treatment, and therefore, without adequate control. Lack of time, care overload or therapeutic inertia are some of the determining factors in this situation. CONCLUSIONS: The INCLIASMA phaseII study highlights the controversies found in routine clinical practice in asthma management, highlighting the continued need for training and offering consensus recommendations that seek to improve asthma management in our country.

Investigation of temperature and frequency dependence of the dielectric properties of multiferroic (La0.8Ca0.2)0.4Bi0.6FeO3 nanoparticles for energy storage application.

In this work we synthesized the multifunctional (La0.8Ca0.2)0.4Bi0.6FeO3 material using a sol-gel process. Structural and morphologic investigations reveal a Pnma perovskite structure at room temperature with spherical and polygonal nanoparticles. A detailed study of the temperature dependence of the dielectric and electrical properties of the studied material proves a typical FE-PE transition with a colossal value of real permittivity at 350 K that allows the use of this material in energy storage devices. Thus, the investigation of the frequency dependence of the ac conductivity proves a correlated barrier hopping (CBH) conduction mechanism to be dominant in the temperature ranges of 150-170 K; the two observed Jonscher's power law exponents, s 1 and s 2 between 180 K and 270 K correspond to the observed dispersions in the ac conductivity spectra in this temperature region, unlike in the temperature range of 250-320 K, the small polaron tunnel (NSPT) was considered the appropriate conduction model.

Structural, morphological, Raman, dielectric and electrical properties of La1-2x Ba x Bi x FeO3 (0.00 ≤ x ≤ 0.20) compounds.

La1-2x Ba x Bi x FeO3 (0.00 ≤ x ≤ 0.20) nanoparticles were prepared by the auto-combustion method using glycine as a combustion fuel. X-ray diffractometry (XRD) measurements confirmed the orthorhombic structure of the synthesized compounds with the Pnma space group as a principal majority phase and showed the presence of a very minor secondary phase when x > 0.1. The nanosize criterion of the prepared compounds was confirmed from the crystallite size values calculated using the Williamson-Hall formalism. The relaxation process has been studied by the frequency dependence of the imaginary parts of impedance and modulus (Z'' and M'') which satisfied the Arrhenius law. Nyquist plots allowed us to obtain an adequate equivalent circuit involving the grains and grain boundary contributions. The activation energies calculated from Z'', M'' and the resistance of both contributions deduced from the Nyquist plots are found to be very similar. The conduction mechanism has been analyzed using the temperature dependence of the exponent Jonscher's power law parameter which confirms the NSPT conduction mechanism type for all compounds with an enhancement of the binding energy of the charge carrier (W H) with the substitution.

Effect of season on the in vitro fertilizing ability of frozen-thawed Spanish bovine spermatozoa.

The purpose of the present study was to evaluate the effects of season on the in vitro fertilizing ability of bovine spermatozoa and subsequent embryo development. Bovine oocytes were matured and fertilized in vitro with Holstein dairy bull sperm cells collected and frozen in different seasons (winter, spring, and summer). On d 2 and 8 postinsemination, cleavage and blastocyst rates, respectively, were recorded; the blastocysts were graded for morphology. The number of sperm cells binding to the zona pellucida of oocytes, together with the number of nuclei in the developing blastocysts, were assessed after staining with Hoechst. No significant differences were observed among seasons in cleavage and embryo development rate. However, the proportion of "advanced blastocysts" was significantly higher in spring compared with winter and summer, with a corresponding decrease in the proportion of early blastocysts in spring compared with winter and summer. The number of sperm cells binding per oocyte was significantly lower in the oocytes inseminated with sperm samples collected in summer compared with winter or spring. Moreover, a significant interaction was observed in the number of sperm cells binding per oocyte between bull and season. Although no significant differences were observed among seasons in the number of nuclei per blastocyst, a significant interaction was observed between bull and season for this variable. Embryo development rate in in vitro fertilization appeared to be affected by season of semen collection, with sperm samples collected in spring being associated with a higher proportion of advanced blastocysts and better morphology than those collected at other times of the year.

Effect of Bi-substitution into the A-site of multiferroic La0.8Ca0.2FeO3 on structural, electrical and dielectric properties.

(La0.8Ca0.2)1-x Bi x FeO3 (x = 0.00, 0.05, 0.10, 0.15 and 0.20) (LCBFO) multiferroic compounds have been prepared by the sol-gel method and calcined at 800 °C. X-ray diffraction results have shown that all samples crystallise in the orthorhombic structure with the Pnma space group. Electrical and dielectric characterizations of the synthesized materials have been performed using complex impedance spectroscopy techniques in the frequency range from 100 Hz to 1 MHz and in a temperature range from 170 to 300 K. The ac-conductivity spectra have been analysed using Jonscher's power law σ(ω) = σ dc + Aω s , where the power law exponent (s) increases with the temperature. The imaginary part of the complex impedance (Z'') was found to be frequency dependent and shows relaxation peaks that move towards higher frequencies with the increase of the temperature. The relaxation activation energy deduced from the Z'' vs. frequency plots was similar to the conduction activation energy obtained from the conductivity. Hence, the relaxation process and the conduction mechanism may be attributed to the same type of charge carriers. The Nyquist plots (Z'' vs. Z') at different temperatures revealed the appearance of two semi-circular arcs corresponding to grain and grain boundary contributions.

Relationships between climate and sperm quality in dairy bull semen: A retrospective analysis.

The aim of the present study was to make a retrospective analysis of the relationship between climatic factors and sperm quality of frozen-thawed semen from bulls kept in temperate climates. Semen samples from 21 European dairy bulls from 2 countries were collected and cryopreserved in winter, spring, and summer. Sperm quality parameters such as kinematics, morphology, plasma membrane integrity, mitochondrial membrane potential, sperm chromatin structure assay, and reactive oxygen species were analyzed and correlated retrospectively with climate factors recorded by the local meteorological office. This study demonstrated that sperm quality parameters are more likely to be correlated with climate factors 1 or 2 mo before semen collection than in the month of semen collection. During the month of sperm collection, sperm kinematics, DNA fragmentation, and hydrogen peroxide production were the only sperm quality parameters related to climate factors, whereas 1 and 2 mo before sperm collection, normal morphology and additional sperm kinematics, in addition to DNA fragmentation and hydrogen peroxide production, were correlated with climate factors. In conclusion, dairy bull sperm quality is affected by climatic conditions, even in so-called temperate zones. The timing of heat stress during spermatogenesis determines which aspects of sperm quality are likely to be affected. Husbandry conditions for bulls used for semen collection should be adapted to allow the animals' physiological responses for temperature regulation within the scrotum to operate fully, to mitigate the effects of increased temperature and humidity. Extremes of temperature should be avoided.

Variation in scale cortisol concentrations of a wild freshwater fish: Habitat quality or seasonal influences?

A significant body of literature suggests that aquatic pollutants can interfere with the physiological function of the fish hypothalamic-pituitary-interrenal (HPI) axis, and eventually impair the ability to cope with subsequent stressors. For this reason, development of accurate techniques to assess fish stress responses have become of growing interest. Fish scales have been recently recognized as a biomaterial that accumulates cortisol, hence it can be potentially used to assess chronic stress in laboratory conditions. We, therefore, aimed to evaluate the applicability of this novel method for cortisol assessment in fish within their natural environment. Catalan chub (Squalius laietanus) were sampled from two sites; a highly polluted and a less polluted (reference) site, in order to examine if habitat quality could potentially influence the cortisol deposition in scales. We also evaluated the seasonal variation in scale cortisol levels by sampling fish at three different time points during spring-summer 2014. In each sampling, blood was collected to complement the information provided by the scales. Our results demonstrated that blood and scale cortisol levels from individuals inhabiting the reference site were significantly correlated, therefore increasing the applicability of the method as a sensitive-individual measure of fish HPI axis activity, at least in non-polluted habitats. Since different environmental conditions could potentially alter the usefulness of the technique, results highlight that further validation is required to better interpret hormone fluctuations in fish scales. Scale cortisol concentrations were unaffected by habitat quality although fish from the polluted environment presented lower circulating cortisol levels. We detected a seasonal increase in scale cortisol values concurring with an energetically costly period for the species, supporting the idea that the analysis of cortisol in scales reveals changes in the HPI axis activity. Taken together, the present study suggests that cortisol levels in scales are more likely to be influenced by mid-term, intense energetically demanding periods rather than by long-term stressors. Measurement of cortisol in fish scales can open the possibility to study novel spatio-temporal contexts of interest, yet further research is required to better understand its biological relevance.

10-MV SBRT FFF IRRADIATION TECHNIQUE IS ASSOCIATED TO THE LOWEST PERIPHERAL DOSE: THE OUTCOME OF 142 TREATMENT PLANS FOR THE 10 MOST COMMON TUMOUR LOCATIONS.

There is a growing interest in the combined use of Stereotactic Body Radiation Therapy (SBRT) with Flattening Filter Free (FFF) due to the high local control rates and reduced treatment times, compared to conventionally fractionated treatments. It has been suggested that they may also provide a better radiation protection to radiotherapy patients as a consequence of the expected decrease in peripheral doses. This work aims to determine this reduction in unattended out-of-field regions, where no CT information is available but an important percentage of second primary cancers occur. For that purpose, ten different cases suitable for SBRT were chosen. Thus, 142 different treatment plans including SBRT, as well as 3D-CRT, IMRT and VMAT (with standard fractionation) in low and high energies for Varian (FF and FFF), Siemens and Elekta machines were created. Then, photon and neutron peripheral dose in 14 organs were assessed and compared using two analytical models. For the prostate case, uncomplicated and cancer free control probability estimation was also carried out. As a general behavior, SBRT plans led to the lowest peripheral doses followed by 3D-CRT, VMAT and IMRT, in this order. Unflattened beams proved to be the most effective in reducing peripheral doses, especially for 10 MV. The obtained results suggest that FFF beams for SBRT with 10 MV represent the best compromise between dose delivery efficiency and peripheral dose reduction.

Hair cortisol and progesterone detection in dairy cattle: interrelation with physiological status and milk production.

Hair cortisol concentrations (HCCs) and hair progesterone concentrations (HPCs) allow monitoring long-term retrospective steroid levels. However, there are still gaps in the knowledge of the mechanisms of steroid deposition in hair and its potential application in dairy cattle research. This study aimed to evaluate the potential uses of hair steroid determinations by studying the interrelations between HCC, HPC, physiological data from cows, and their milk production and quality. Cortisol and progesterone concentrations were analyzed in hair from 101 milking Holstein Friesian cows in a commercial farm. Physiological data were obtained from the 60 d prior to hair collection. Moreover, productive data from the month when hair was collected and the previous one were also obtained as well as at 124 d after hair sampling. Significant but weak correlations were found between HCC and HPC (r = 0.25, P < 0.0001) and between HPC and age (r = 0.06, P = 0.0133). High HCC were associated with low milk yields from the 2 previous months to hair sampling (P = 0.0396) and during the whole lactation (P < 0.0001). High HCC were also related to high somatic cell count (P = 0.0241). No effect of HCC on fat or protein content was detected. No significant correlations were detected between hair steroid concentrations and pregnancy status, days of gestation, parturition category (primiparous vs multiparous), number of lactations or days in milk. The relationship between physiological variables and HCC or HPC could depend on the duration of the time period over which hair accumulates hormones. Steroid concentrations in hair present high variability between individuals but are a potential tool for dairy cattle welfare and production research by providing a useful and practical tool for long-term steroid monitoring.

Analysis of ZP1 gene reveals differences in zona pellucida composition in carnivores.

The zona pellucida (ZP) is an extracellular envelope that surrounds mammalian oocytes. This coat participates in the interaction between gametes, induction of the acrosome reaction, block of polyspermy and protection of the oviductal embryo. Previous studies suggested that carnivore ZP was formed by three glycoproteins (ZP2, ZP3 and ZP4), with ZP1 being a pseudogene. However, a recent study in the cat found that all four proteins were expressed. In the present study, in silico and molecular analyses were performed in several carnivores to clarify the ZP composition in this order of mammals. The in silico analysis demonstrated the presence of the ZP1 gene in five carnivores: cheetah, panda, polar bear, tiger and walrus, whereas in the Antarctic fur seal and the Weddell seal there was evidence of pseudogenisation. Molecular analysis showed the presence of four ZP transcripts in ferret ovaries (ZP1, ZP2, ZP3 and ZP4) and three in fox ovaries (ZP2, ZP3 and ZP4). Analysis of the fox ZP1 gene showed the presence of a stop codon. The results strongly suggest that all four ZP genes are expressed in most carnivores, whereas ZP1 pseudogenisation seems to have independently affected three families (Canidae, Otariidae and Phocidae) of the carnivore tree.

Magnetocaloric study, critical behavior and spontaneous magnetization estimation in La0.6Ca0.3Sr0.1MnO3 perovskite.

A detailed study of structural, magnetic and magnetocaloric properties of the polycrystalline manganite La0.6Ca0.3Sr0.1MnO3 is presented. The Rietveld refinement of X-ray diffraction pattern reveals that our sample is indexed in the orthorhombic structure with Pbnm space group. Magnetic measurements display a second order paramagnetic (PM)/ferromagnetic (FM) phase transition at Curie temperature T c = 304 K. The magnetic entropy change (ΔS M) is calculated using two different methods: Maxwell relations and Landau theory. An acceptable agreement between both data is noted, indicating the importance of magnetoelastic coupling and electron interaction in magnetocaloric effect (MCE) properties of La0.6Ca0.3Sr0.1MnO3. The maximum magnetic entropy change (-ΔS max M) and the relative cooling power (RCP) are found to be respectively 5.26 J kg-1 K-1 and 262.53 J kg-1 for µ 0 H = 5 T, making of this material a promising candidate for magnetic refrigeration application. The magnetic entropy curves are found to follow the universal law, confirming the existence of a second order PM/FM phase transition at T c which is in excellent agreement with that already deduced from Banerjee criterion. The critical exponents are extracted from the field dependence of the magnetic entropy change. Their values are close to the 3D-Ising class. Scaling laws are obeyed, implying their reliability. The spontaneous magnetization values determined using the magnetic entropy change (ΔS M vs. M 2) are in good agreement with those obtained from the classical extrapolation of Arrott curves (µ 0 H/M vs. M 2). The magnetic entropy change can be effectively used in studying the critical behavior and the spontaneous magnetization in manganites system.

Coenzyme Q10 supplementation during in vitro maturation of bovine oocytes (Bos taurus) helps to preserve oocyte integrity after vitrification.

Oocyte vitrification causes less cell stress than slow cooling, but cytoskeletal and spindle alterations may occur affecting the oocyte competence. In vitro maturation (IVM) supplementation with different antioxidant molecules has been performed to attenuate this harmful stress. Coenzyme Q10 (CoQ10 ) supplementation has previously shown to have positive effects in bovine and mouse in vitro embryo development. The aim of this study was to evaluate the effects of CoQ10 during bovine oocyte IVM and vitrification. Cumulus-oocyte complexes (COCs) (n = 311) were cultured under standard maturation conditions with 0 µM (control), 25 µM and 50 µM CoQ10 supplementation. After 22 hr, a cohort of 170 oocytes both from the control and from CoQ10 -supplemented groups were vitrified, warmed and returned to incubation until 24 hr of maturation, while the rest of the oocytes (n = 141) remained fresh. Then, oocyte survival was assessed morphologically by stereomicroscopy. Oocytes from all groups were then fixed and stained for assessing cortical granules (CG) migration and nuclear stage. High rates of oocyte MII progression and appropriate CG migration as a continuous layer beneath the plasma membrane were obtained both in control and in CoQ10 groups. Results showed that although vitrification has great impact in survival of IVM bovine oocytes, 50 µM CoQ10 supplementation significantly improved oocyte survival (p = .045) and reduced the premature CG exocytosis, helping to preserve the CG migration pattern (31.3% control vs. 54.5% in 50 µM CoQ10 ; p = .039), attenuating the negative effects of vitrification.

Effect of heat stress during in vitro maturation on developmental competence of vitrified bovine oocytes.

Heat-shock protein 70 (HSP70) plays a crucial role as intracellular cytoprotectant and molecular chaperone. A phenomenon of heat stress (HS) leads to production of these proteins that could be beneficial to cells during cryopreservation, which is also a stressful process for the cell. This study aimed to evaluate the protective effect of exposure of bovine oocytes to moderate HS during in vitro maturation (IVM) prior vitrification. First, oocytes were subjected to HS (41.5°C for 1 hr) at 0, 4, 8, 12 or 16 of IVM. Oocytes in vitro matured for 20 hr served as control group. Presence of HSP70 was detected at 20 hr by immunofluorescence. HSP70 expression was significantly higher when oocytes were subjected to HS at 8 hr of IVM. Next, oocytes were distributed into four groups: Control: IVM oocytes; VIT: oocytes vitrified/warmed at 20 hr of IVM; HS: oocytes subjected to HS at 8 hr of IVM; HS-VIT: oocytes subjected to HS at 8 hr of IVM and vitrified/warmed at 20 hr of IVM. Oocytes were fertilized at 24 hr of IVM, and cleavage and blastocyst yield were assessed. No significant differences were observed among treatments when cleavage rate was evaluated. However, fresh control and HS oocytes resulted in a significantly higher (p < .05) blastocyst rate when compared to VIT and HS-VIT groups, although no significant differences within fresh or vitrified groups were observed. In conclusion, HS did not have a negative impact on the oocyte competence but HS applied before vitrification, offered no benefits for embryo development.

Increased sperm cell production in ageing roosters by an oral treatment with an aromatase inhibitor and a natural herbal extract designed for improving fertility.

Rooster fertility peaks between 30 and 40 weeks of age and declines rapidly from 50 weeks of age. This is linked to a reduction in the number of spermatozoa in the ejaculate due to high density of spermatids in the seminiferous tubules of low-fertility roosters. In this study, we assessed the effects over spermatogenesis of both letrozole, an aromatase inhibitor, and a commercial herbal extract designed for improving fertility composed by Tribulus, Cinnamomum, Zingiber and Sativus. Forty-two-week-old Ross 308 roosters (n = 24) were distributed into four groups: control, letrozole (0.03 mg/kg), herbal extract (0.04 ml/kg) and letrozole+herbal extract. After 14 weeks of daily oral supplementation, their testes and epididymides were weighed, fixed and sectioned for assessment of spermatogenesis and quantification of sperm cells inside the lumen. Differences in seminiferous tubules measurements and density of sperm cells were tested using R software (version 3.0.1). Although body weight was not affected by the treatment, testes from animals treated with the combination of letrozole and herbal extracts were heavier than those from control animals. Animals treated with either letrozole or herbal extract, or their combination, showed a significant higher number of sperm cells inside the seminiferous tubules and epididymis than control animals (p < .05). These data suggest that the use of letrozole and the herbal extract could improve sperm cell production in ageing roosters. Future studies are needed to disclose the causal mechanisms involved and its effect on fertility and ejaculate features.

Effects of season on bull sperm quality in thawed samples in northern Spain.

The aim of the present study was to evaluate the possible effects of climate factors on sperm quality of Holstein dairy bulls housed in northern Spain. Semen samples from 11 Holstein dairy bulls were collected and cryopreserved in winter, spring and summer. Sperm quality parameters such as motility, morphology, plasma membrane integrity, acrosome status, mitochondrial membrane potential, DNA fragmentation index and reactive oxygen species were assessed. Samples collected in spring showed higher mean values of total and progressive motility compared with samples collected in winter. Mean values of average path velocity and straight-line velocity were higher in spring than in summer. The proportion of viable spermatozoa was higher in spring than in winter as was the proportion of viable spermatozoa with non-reacted acrosome. The proportion of live cells that were not producing superoxide or hydrogen peroxide was higher in samples collected in spring than in winter. No differences were found in sperm morphology or the DNA fragmentation index among seasons. In conclusion, results suggest that sperm quality of bulls housed in northern Spain is affected by season. Samples collected in spring appear to have better sperm quality than samples collected in other seasons.

Acute ACTH-induced elevations of circulating cortisol do not affect hair cortisol concentrations in calves.

In recent times, the detection of cortisol in hair is intended to be used as an animal-based indicator for the assessment of chronic stress. However, the relationship between the ability to report average values of long-term circulating cortisol concentrations and the sensitivity to acute peaks of cortisol is still unclear. To gain insight into this relationship, 24 Holstein-Friesian bull calves under the same management conditions were used in this study. Two injections of ACTH (at D0 and D7) were administrated to twelve animals with the aim to create two acute increases of serum cortisol concentrations. Blood samples were taken in order to determine the duration of serum cortisol peaks and to confirm a mediated response by the administration of ACTH. Cortisol concentrations from 14-day-old white hair samples collected from forehead and hip were analysed separately by EIA and compared with those from the control group. Serum cortisol analyses revealed an acute increase of cortisol concentrations for approximately three hours after each ACTH administration. Concentrations of hair cortisol from forehead and hip locations showed no differences between ACTH-administrated and control animals. Hair cortisol concentrations from 14-day old samples were not altered by two acute elevations of serum cortisol suggesting that hair cortisol is not masked by short and non-recurrent moments of stress. These results are a step forward in the validation of hair cortisol detection as a robust integrative measure of serum cortisol concentrations from an extended period of time.