scholarly journals Evaluating the impact of breed, pregnancy, and hair coat on body temperature and sweating rate of hair sheep ewes in the tropics

2017 ◽  
Vol 95 (7) ◽  
pp. 2936
Author(s):  
R. W. Godfrey ◽  
W. D. Preston ◽  
S. R. Joseph ◽  
L. LaPlace ◽  
P. E. Hillman ◽  
...  
2017 ◽  
Vol 95 (7) ◽  
pp. 2936-2942 ◽  
Author(s):  
R. W. Godfrey ◽  
W. D. Preston ◽  
S. R. Joseph ◽  
L. LaPlace ◽  
P. E. Hillman ◽  
...  

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 169-170
Author(s):  
Bob Godfrey ◽  
Amran Nero ◽  
Sue Lakos

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.


2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 200-201
Author(s):  
Robert Godfrey ◽  
Sue A Lakos

Abstract The study was conducted to evaluate body temperature of hair sheep ewes at various stages of the production cycle in an accelerated lambing system in the tropics. Multiparous St. Croix White (STX: n = 7) and Dorper x STX (DRPX; n = 7) ewes lambing in October and raising single lambs weaned at 120 d were used. Synchronized breeding began at 96 d postpartum. Vaginal temperature (VT) was measured at 10-min intervals for 96 h at 38 and 66 d post-partum (PP1, PP2) and at 2 days after mating (PM) using data loggers. Daily minimum, maximum and range of VT were determined for ewes within PP1, PP2 and PB. Data were analyzed using GLM procedures of SAS with breed, day and time (PP1, PP2, PM) in the model. Mean ambient temperature, temperature-humidity index and solar radiation at PP1, PP2 and PM were 24.8 °C, 25.2 °C, 23.8 °C, and 74.7, 74.9, 73.3, and 180 W/m2, 160 W/m2 and 155 W/m2, respectively. Minimum VT was lower (P < 0.002) in STX than DRPX ewes at PP1, PP2 but not PM (38.27 ± 0.04 vs 38.44 ± 0.04 °C, 38.16 ± 0.04 vs 38.33 ± 0.04 °C, 38.47 ± 0.04 vs 38.58 ± 0.04 °C, respectively). There was no difference in maximum VT between breed or time (P > 01.0). There was no breed difference (P > 0.10) in range of VT, but the range of VT was lower (P < 0.0001) at PM compared to PP1 and PP2 (1.22 ± 0.04 vs 1.77 ± 0.04 vs 1.63 ± 0.04 °C, respectively). These results show that tropically adapted STX ewes have lower body temperatures, as shown by the lower minimal VT which indicates a degree of nighttime cooling, during the postpartum period compared to DRPX ewes in a tropical environment.


2017 ◽  
Vol 95 (suppl_4) ◽  
pp. 247-247
Author(s):  
R. W. Godfrey ◽  
A. Nero ◽  
G. Roberts ◽  
S. A. Lakos

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Kazuyuki Miyamoto ◽  
Keisuke Suzuki ◽  
Hirokazu Ohtaki ◽  
Motoyasu Nakamura ◽  
Hiroki Yamaga ◽  
...  

Abstract Background Heatstroke is associated with exposure to high ambient temperature (AT) and relative humidity (RH), and an increased risk of organ damage or death. Previously proposed animal models of heatstroke disregard the impact of RH. Therefore, we aimed to establish and validate an animal model of heatstroke considering RH. To validate our model, we also examined the effect of hydration and investigated gene expression of cotransporter proteins in the intestinal membranes after heat exposure. Methods Mildly dehydrated adult male C57/BL6J mice were subjected to three AT conditions (37 °C, 41 °C, or 43 °C) at RH > 99% and monitored with WetBulb globe temperature (WBGT) for 1 h. The survival rate, body weight, core body temperature, blood parameters, and histologically confirmed tissue damage were evaluated to establish a mouse heatstroke model. Then, the mice received no treatment, water, or oral rehydration solution (ORS) before and after heat exposure; subsequent organ damage was compared using our model. Thereafter, we investigated cotransporter protein gene expressions in the intestinal membranes of mice that received no treatment, water, or ORS. Results The survival rates of mice exposed to ATs of 37 °C, 41 °C, and 43 °C were 100%, 83.3%, and 0%, respectively. From this result, we excluded AT43. Mice in the AT 41 °C group appeared to be more dehydrated than those in the AT 37 °C group. WBGT in the AT 41 °C group was > 44 °C; core body temperature in this group reached 41.3 ± 0.08 °C during heat exposure and decreased to 34.0 ± 0.18 °C, returning to baseline after 8 h which showed a biphasic thermal dysregulation response. The AT 41 °C group presented with greater hepatic, renal, and musculoskeletal damage than did the other groups. The impact of ORS on recovery was greater than that of water or no treatment. The administration of ORS with heat exposure increased cotransporter gene expression in the intestines and reduced heatstroke-related damage. Conclusions We developed a novel mouse heatstroke model that considered AT and RH. We found that ORS administration improved inadequate circulation and reduced tissue injury by increasing cotransporter gene expression in the intestines.


Blood ◽  
2012 ◽  
Vol 120 (13) ◽  
pp. 2600-2609 ◽  
Author(s):  
Maegan L. Capitano ◽  
Michael J. Nemeth ◽  
Thomas A. Mace ◽  
Christi Salisbury-Ruf ◽  
Brahm H. Segal ◽  
...  

Abstract Neutropenia is a common side effect of cytotoxic chemotherapy and radiation, increasing the risk of infection in these patients. Here we examined the impact of body temperature on neutrophil recovery in the blood and bone marrow after total body irradiation (TBI). Mice were exposed to either 3 or 6 Gy TBI followed by a mild heat treatment that temporarily raised core body temperature to approximately 39.5°C. Neutrophil recovery was then compared with control mice that received either TBI alone heat treatment alone. Mice that received both TBI and heat treatment exhibited a significant increase in the rate of neutrophil recovery in the blood and an increase in the number of marrow hematopoietic stem cells and neutrophil progenitors compared with that seen in mice that received either TBI or heat alone. The combination treatment also increased G-CSF concentrations in the serum, bone marrow, and intestinal tissue and IL-17, IL-1β, and IL-1α concentrations in the intestinal tissue after TBI. Neutralizing G-CSF or inhibiting IL-17 or IL-1 signaling significantly blocked the thermally mediated increase in neutrophil numbers. These findings suggest that a physiologically relevant increase in body temperature can accelerate recovery from neutropenia after TBI through a G-CSF–, IL-17–, and IL-1–dependent mechanism.


2012 ◽  
Vol 279 (1742) ◽  
pp. 3520-3526 ◽  
Author(s):  
Brian Tilston Smith ◽  
Amei Amei ◽  
John Klicka

Climatic and geological changes across time are presumed to have shaped the rich biodiversity of tropical regions. However, the impact climatic drying and subsequent tropical rainforest contraction had on speciation has been controversial because of inconsistent palaeoecological and genetic data. Despite the strong interest in examining the role of climatic change on speciation in the Neotropics there has been few comparative studies, particularly, those that include non-rainforest taxa. We used bird species that inhabit humid or dry habitats that dispersed across the Panamanian Isthmus to characterize temporal and spatial patterns of speciation across this barrier. Here, we show that these two assemblages of birds exhibit temporally different speciation time patterns that supports multiple cycles of speciation. Evidence for these cycles is further corroborated by the finding that both assemblages consist of ‘young’ and ‘old’ species, despite dry habitat species pairs being geographically more distant than pairs of humid habitat species. The matrix of humid and dry habitats in the tropics not only allows for the maintenance of high species richness, but additionally this study suggests that these environments may have promoted speciation. We conclude that differentially expanding and contracting distributions of dry and humid habitats was probably an important contributor to speciation in the tropics.


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