Summary Aerobic capacity and fitness was studied in three different horse breeds (Andalusian, Arabian and Anglo‐Arabian) using a four‐level exercise test of gradually increasing intensity (15, 20, 25 and 30 km/h). The lactate concentration at the first three exercise levels was significantly lower for Arabian and Anglo‐Arabian horses relative to Andalusian horses, but similar for the three breeds at the last level. Arabian and Anglo‐Arabian horses reached a higher rate than Andalusian horses at plasma lactate concentration of 2 mmol/l (VLA2) and 4 mmol/l (VLA4). Andalusian horses exhibited a significantly lower heart rate at rest than the other two breeds, but the differences virtually disappeared at 15 km/h. At 20 km/h, Andalusian horses reached a higher heart rate than Arabian and Anglo‐Arabian horses; at 25 km/h, however, their heart rate only exceeded that of Anglo‐Arabian horses. Finally, no significant differences between breeds were observed at 30 km/h. No differences between breeds as regards heart rate were found if this was expressed as a function of lactate plasma concentrations of 2 mmol/l (HRLA2) and 4 mmol/l (HRLA4). At a heart rate of 150 (VHR150) and 200 beat/min (VHR200), Andalusian horses achieved the lowest speeds.

ABSTRACT:The aim of this study was to evaluate the effect of aerobic training (16 weeks -T1 and 24 weeks -T2) on oxidative stress biomarkers. To this end, GSH, GSH-peroxidase (GSH-Px) and catalase (CAT) activity were analysed in plasma. Nine bulls (3-4 years), were included in this work. The exercise training protocol was performed in a track ("taurodromo") three days per week for 24 weeks and consisted of 400 m warming up, 1200 m to 4-5 m/s, two minutes' resting, 1200 m to 4-5 m/s and, finally, 400 m walking. The results reflected that GSH-Px activity was higher at T1 (6.18 ± 0.45) than at baseline (T0; 2.31 ± 0.08) while the GSH level (2.98 ± 0.37) was lower vs. T0 (14.59 ± 3.40). Moreover, there were significant increases in GSH-Px (18.23 ± 1.36) and CAT (2.52 ± 0.04) activities and the recovery of basal values in GSH (11.75 ± 2.84) in T2. In conclusion, the type of training carried out in this study involved two well-defined stages: (i) a period of perturbation, followed by (ii) adaptation. The former stage was characterised by the induction of oxidative stress manifested as a decrease in the GSH, and the latter (T2) by the recovery of this non-enzymatic antioxidant.

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The aim of the present work was to transfer a wider concept of teamwork and self-learning to the laboratory, encouraging students' capabilities when seeking, acquiring, and processing knowledge. This educational innovation was carried out with a total of 38 students (fourth year of degree in Biology) in the area of physiology (Advances in Reproduction course) at University of Córdoba in Córdoba, Spain. The design of the project's application methodology consisted of establishing a way in which problems would be tackled in the practical classes. For this purpose, the different tasks were set up so that students could relate them to the concepts learned in the theory classes. On the first day of class, the project was presented to the students. Groups of two to three students worked in the laboratory and set up an outline of the protocol of the practical work that they had done. This outline was performed individually and sent to the lecturers through a learning management system (Moodle). The teachers gave feedback and assessed student submissions. Upon finishing the course, students completed a survey. The project-based learning method promotes practical self-learning on the part of students. This methodology demonstrated to us that it stimulates a critical and self-critical capacity in students, both individually and in groups, and that writing didactic practical material helped students to enhance their theory knowledge. The experiment was a success in view of the scores obtained upon finishing the subject.

Summary Analysis of electrical ventricular systole in the sheep. 1. Depolarization phenomena Over a time period from birth to one year a study was made of the ECG in sheep of the early maturing merino breed in order to determine the influence of physical maturation on the process of ventricular depolarization. The QRS complex undergoes an increase in length in the course of bodily development; the electrical potential, on the other hand, is significantly lower in the 1‐year old animal. The morphological structure also seems to be involved since in V10 the Q‐spike is absent in the newborn; it becomes more frequent with increasing age. The length of both the RR interval and the QT interval undergo and increase from 20 days of age; there also occurs a highly significant correlation between the two intervals. The length of ventricular activation showed, however, no significant correlation with the length of the cardiac cycle. Resumen Se han analizado ECG procedentes de ovinos de raza Merino Precoz, a lo largo de un periodo de tiempo comprendido entre el nacimiento y la edad de 1 año, con el fin de determinar la influencia de la maduración física sobre el proceso de despolarización ventricular. El complejo QRS experimenta un aumento en su duración a medida que se produce la maduración física; por el contrario, el voltaje se muestra significativamente inferior en los individuos de 1 año. También la morfología parece verse afectada ya que, en V10, la onda ‘q’ está ausente en los individuos recién nacidos, haciéndose más frecuente a medida que aumenta la edad. Tanto la durción del intervalo RR como del intervalo QT experimenta un incremento a partir de los 20 días de edad, obteniéndose, además, una correlación muy significativa entre ambos. Sin embargo, la duración de la activación ventricular no presenta correlación significativa con la duración del ciclo cardíaco. Zusammenfassung Analyse der elektrischen Herzkammersystole bei Schafen I. Depolarisationsphänomene Während einer Zeitperiode, die von der Geburt bis zum Alter eines Jahres geht, wurden Elektrokardiogramme untersucht, die von Schafen der Frühreifen‐Merino‐Rasse stammten zwecks Feststellung des Einflusses der physischen Reife auf den Prozeß der ventrikulären Depolarisation. Der QRS‐Komplex erfährt einen Zuwachs in seiner Länge im Laufe der Entwicklung der körperlichen Reife; die elektrische Spannung hingegen ist signifikant niedriger bei den einjährigen Individuen. Der morphologische Aufbau scheint ebenfalls betroffen zu sein, da bei V10 die Q‐Zacke bei den Neugeborenen ausblieb; sie wird häufiger mit zunehmendem Alter. Sowohl die Länge des Intervalls RR wie die des Intervalls QT erfahren einen Zuwachs ab einem Alter von 20 Tagen; dabei wird außerdem eine hochsignifikante Korrelation zwischen beiden Intervallen erzielt. Jedoch weist die Länge der ventrikulären Aktivierung keine signifikante Korrelation mit der Herzzykluslänge auf.

The novel aim of this study was to describe the reference values of different haematological and biochemical parameters in the Spanish purebred horse (Andalusian, SPB) in each of the stages of a programmed exercise on a treadmill system, and to establish heritability and genetic correlations for these haematological and biochemical parameters. For this, 94 young SPB male horses (4.22 6 2.27 years old) were used. An increasing intensity exercise test at 4, 5, 6 and 7 m/s was carried out on a treadmill (6% inclination). Total red blood cells, total white blood cells, neutrophils and lymphocytes counts; haematocrit, haemoglobin, lactate, uric acid, creatinine and total plasma proteins concentrations and aspartate transaminase, lactate dehydrogenase, creatine-quinase activities were determined. To conclude: (i) the reference values for each parameter were determined for each of the exercise test stages (ii) all the parameters analysed manifested a medium-high heritability and a high repeatability. These results will, in the near future, determine the measuring guidelines for improving the SPB horse's athletic ability on an objective treadmill system and for selecting these animals in response to those parameters.

Studies on the electrical ventricular systole in the sheep 11. RepolarizationThe effects of physical maturation on the parameters related to ventricular repolarization in sheep at different ages were studied. The height of the T wave showed the most significant decrease between the first and fourth day of postnatal life; on the contrary, its duration showed a significant increase up to the second month of life. The wave form was also affected by physical maturation, in that the polarity of the T wave in adults differs from that of young individuals in the D-, Iand aVFleads.The ST segment, which is increased in its duration with age increase, showed very significant correlations with the duration of the cardiac cycle and the duration of the ventricular electrical systole.El proceso de repolarizacion viene representado en el ECG por el interval0 ST-T, constituido por el segmento ST y la onda T. Para algunos autores ambos parimetros son indesligables, ya que en algunas especies corn0 caballo, delfin y pinnipedos en general (HAMLIN y cols., 1970; HAMLIN y cols., 1972), es dificil establecer en quC rnornento acaba el citado segmento y comienza la onda T; incluso en ovinos, bajo deterrninadas circunstancias (hipoxia fetal), la elevation del segmento ST se confunde con la rarna ascendente de la onda T (ROSEN, 1976;HOKEGARD, 1979). Por otra parte, la onda T parece ser la mis controvertida de todas las deflexiones electrocardiogrificas, ya que el sentido de la recuperacidn ventricular puede modificarse bajo deterrninadas circunstancias (hipoxia, alteraciones rnetabolicas, disturbios electroliticos, trabajo muscular, etc.) (LEPESCHKIN,

The consequences of physical maturation on the orientation of the mean vector of auricular activation in Merino Precoz sheep at different ages has Peen analysed.The results show that the vectorial magnitudes of AP and SAP undergo a significant decrease at 20 days and between 3 months and 1 year of age. Conversely, physical maturation does not seem to have any effect on the sequence of auricular activation, since the P mean spatial vector takes a sinistrocaudal and slightly ventral orientation in all ages analysed.