PSXVI-3 Evaluating the lag between body temperature and ambient temperature in hair sheep ewes in the tropics.

摘要

The objective of this study was to evaluate the relationship between environment and body temperature of non-pregnant, non-lactating St. Croix White (STX, 5.6 y of age, n = 10) and Dorper x St Croix White (DRPX, 3.8 y of age, n = 10) ewes grazing pasture. Temperature data loggers recorded vaginal temperature (VT) at 10-min intervals. Ambient temperature (AT), relative humidity (RH) were measured using an onsite weather station. The VT, AT and RH data collected for 96-h periods in July and August were a subset of a larger data set coinciding with the hottest time of the year. Data were analyzed using GLM procedures of SAS with breed, month and time of day in the model. The AT, RH and temperature-humidity index (THI) were 28.2 °C, 78.2 % and 79.6, respectively. There was no difference (P > 0.10) in minimum or maximum VT between STX and DRPX ewes (38.55 ± 0.03 vs 38.55 ± 0.03 °C or 39.45 ± 0.03 vs 39.52 ± 0.03 °C, respectively). There was no difference (P > 0.10) in time of day for minimum VT between STX and DRPX ewes (453.5 ± 10.7 vs 428.5 ± 10.7 min, respectively). The time of day for maximum VT was greater (P < 0.006) for STX than for DPRX ewes (1072.0 ± 10.7 vs 1030.0 ± 10.7 min, respectively). The lag time between minimum AT and VT was not different (P < 0.10) between STX and DRPX ewes (238.5 ± 15.6 vs 213.5 ± 15.6 min, respectively). The lag time between maximum AT and VT was greater (P < 0.06) for STX than for DRPX ewes (238.5 ± 15.6 vs 211.7 ± 15.6 min, respectively). The greater lag time for maximum VT of STX ewes may be a part of their adaptation to the tropical climate.