160 A comparison of body temperature among pregnant, non-pregnant and lactating hair sheep ewes in the tropics

Abstract

Abstract St. Croix White hair sheep are well adapted to the tropics. The objective of this study was to evaluate the impact of pregnancy on body temperature of hair sheep. Multiparous St. Croix White ewes (n = 9) were evaluated over 4 d at 128 d of gestation (PREG) and 45 d postpartum (PP) while lactating. A set of non-pregnant, non-lactating (DRY) ewes (n = 9) were also evaluated at each time. Temperature data loggers recorded vaginal temperature (VT) at 10-min intervals for 96 h. Ewes were kept in a 0.6 ha pasture. Data were analyzed using GLM procedures of SAS for repeated measures with pregnancy status and time of day in the model. Mean temperature and solar radiation were 26.3 °C and 212.3 W/m2, respectively. Ewe VT was lowest (P < 0.0001) between 0 and 0700 h and greatest between 1400 and 1900 h (38.21 ± 0. 02 vs 39.11 ± 0.02 °C, respectively). Ewe VT was lowest (P < 0.004) in PREG ewes compared to DRY or PP ewes (38.38 ± 0.02 vs 38.76 ± 0.02 vs 38.77 ± 0.02, °C, respectively). The VT of PREG ewes was lower than that of DRY ewes (P < 0.0001) during 0 to 0480 and 1920 to 2400 h, but there was no difference (P > 0.10) between 0480 and 1920 h. There was no difference in VT between PP and DRY ewes at any time of the day (P > 0.10). The VT of PREG ewes was lower than that of PP ewes (P < 0.0001) during 0 to 0480 and 1920 to 2400 h, but there was no difference (P > 0.10) between 0480 and 1920 h. The lower VT of PREG ewes compared to PP and DRY ewes may be a protective mechanism for the developing fetus.