Investigation into the effect of season on oestrus in gilts over two years of climate adaptation

This study examined the changes in age at first oestrus, the weaning-to-oestrus interval (WEI), and duration of oestrus (DE) in a Yorkshire sow population during two years of adaptation from a northern (55°48′N, 9°13′W) European region to a southern (44°03′N, 23°35′W) one. The adaptation process induced a grouping effect of gilts around the mean age of the onset of puberty. Autumn and spring were characterized by the most enhanced gilt grouping effect at 201 to 210 days of age. The same effect was found for oestrus duration, which declined from a 12- to 96-hour range in the first year to an 18- to 90-hour range in the second year. The mean age of first oestrus was 0.8 days significantly lower in the second year compared with the first; the maximal lowering (1.7 days) occurred in the winter season. The WEI decreased significantly from the first to the second year in all four seasons, by a mean annual value of 0.88 days (15.9%). DE increased by 6.5 hours (significantly for all seasons) from the first year to the next. DE showed an ascending evolution from winter to spring and descending from summer to autumn, during each monitored year. Adaptation influences the oestrus in sows. The age to puberty and WEI tended to decrease, while DE tended to increase, with a simultaneous decrease in the variability of these oestrus parameters.Keywords: Age of puberty, climate conditions, length of oestrus, weaning to oestrus interva

Parâmetros eletrocardiográficos de equinos Puro Sangue Árabe submetidos a exercício prolongado de enduro Electrocardiographic parameters of Arabian horses submitted to prolonged exercise of endurance

Foram estabelecidos os parâmetros eletrocardiográficos de 20 equinos Puro Sangue Árabe em repouso e após exercício prolongado de enduro. A frequência cardíaca média foi de 35,85bpm em repouso, com predominância do ritmo sinusal, e de 53,78bpm, com taquicardia sinusal após o exercício. Como variação fisiológica, observou-se marcapasso migratório, e como não fisiológica, complexo ventricular prematuro. No pós-exercício, ocorreu aumento da amplitude das ondas P, R, S e T, com onda P tendendo a se tornar única em 35% dos animais e bífida positiva em 65%, e a onda T monofásica positiva. Houve redução da duração das ondas, dos intervalos e dos segmentos, e alongamento do QTc; porém, o complexo QRS quase não se alterou. O eixo elétrico, no plano frontal, apresentou desvios à direita e à esquerda em repouso sugestivo de aumento de câmara e hipertrofia secundárias ao treinamento, ao passo que, após o exercício, demonstrou desvio extremo para a direita, indicando alterações eletrolíticas. O escore cardíaco médio foi de 128,45ms, o que caracteriza os animais como atletas, sendo reduzido a 118,60ms após o exercício.<br>Electrocardiographic parameters of 20 Thoroughbred Arabian horses were established at rest and after prolonged endurance exercise. The mean heart rate was 35.85bpm at rest with predominant sinus rhythm, and 53.78bpm with sinus tachycardia after exercise. As physiological variation, wandering pacemaker was observed, and as non physiological, premature ventricular complex was noted. At post-exercise there was an increase of the amplitude of waves P, R, S and T, with P wave tending to become single in 35% of the animals and bifid positive in 65%, and with monophase positive T wave. There was a reduction in the duration of the waves, intervals and segments, and elongation of QTc, but the QRS complex hardly changed. The electrical axis in the frontal plane showed deviations to the right and to the left at rest, suggesting chamber enlargement and hypertrophy secondary to training, while after the exercise it showed extreme deviation to the right, indicating electrolyte imbalances. The average heart score was 128.45ms, which features the animals as athletes, being reduced to 118.60ms after exercise