03306naa a2200433 a 450000100080000000500110000800800410001902400560006010000240011624501790014026000090031952019590032865000110228765000210229865000260231965000190234565000210236465000100238565000140239565300250240965300230243465300180245765300150247565300090249065300290249965300270252865300210255570000220257670000220259870000270262070000210264770000270266870000190269570000230271470000270273770000230276470000180278777300670280521533642023-04-26       2023    bl uuuu     u00u1 u    #d7 ahttps://doi.org/10.1016/j.jtherbio.2023.1035462DOI1 aRODRIGUES, J. N. D.  aClimatic seasons and time of the day influence thermoregulation and testicular hemodynamics in Santa Inês rams raised under humid tropical conditions.h[electronic resource]  c2023  aAbstract: This study evaluated the possible association between the diurnal variations of climatic factors during the rainy (RS) or less rainy (LS) seasons on the testicular hemodynamics and thermoregulatory responses of hair sheep rams raised in a humid tropical climate. Santa Inês rams (n = 6) underwent evaluation of general and testicular physiological parameters (heart and respiratory rates, internal and scrotal temperatures, internal-scrotal temperature gradient, scrotal distention, and color Doppler ultrasound evaluation of the spermatic cords and spectral analyses of testicular arteries) over six consecutive weeks per season at three separate times daily (morning = 8:00 a.m., noon = 12:00 p.m., and afternoon = 5:00 p.m.) during the RS and LS. Climatic air temperature and relative humidity data were recorded, and the temperature and humidity index (THI) was calculated. Higher thermal challenge was observed in LS relative to RS (air temperature = 28.0 vs. 30.9 °C; relative humidity = 84.1 vs. 69.9%; THI = 80.0 vs. 82.5; P &lt 0.05). In both seasons, respiratory rate and internal temperature were normal, demonstrating the animals? adaptability. In RS, however, a higher scrotal temperature was recorded in relation to LS (35.0 vs. 34.7 °C; P &lt 0.05), with a gradual increase from morning to afternoon. Lower resistivity (0.40 vs. 0.64; P &lt 0.05) and pulsatility (0.55 vs. 1.14; P &lt 0.05) indices, and a higher rate of high-velocity blood flow of testicular arteries (71.1 vs. 60.6%; P &lt 0.05) were observed in RS compared to LS. The lowest correlations between testicular hemodynamic, physiological variables, and environmental parameters (P &lt 0.05) were observed in the morning. In conclusion, testicular thermoregulation and testicular hemodynamics were influenced by the climatic seasons and time of the day, being more efficient in the LS season and with less interference from environmental factors in the morning.  aBrazil  aClimatic factors  aEnvironmental factors  aSpermatic cord  aThermoregulation  aOvino  aUltrassom  aCordão espermático  aDoppler ultrasound  aHaemodynamics  aHair sheep  aILPF  aPhysiological parameters  aTesticular hemodynamic  aTropical climate1 aGUIMARÃES, J. D.1 aFONSECA, J. F. da1 aPENITENTE-FILHO, J. M.1 aRANGEL, P. S. C.1 aRAMÍREZ LÓPEZ, C. J.1 aFREITAS, R. S.1 aCASTILHO, E. F. de1 aRODRIGUES, L. F. de S.1 aOLIVEIRA, M. E. F.1 aGARCIA, A. R.  tJournal of Thermal Biologygv. 114, article 103546, May, 2023.