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|Title:||The time-course of physiological variation in rate function and acid-base disturbance in the domestic pig subjected to thermal stress|
|Author(s):||Park, Thomas Frank, Jr|
|Doctoral Committee Chair(s):||Harrison, Paul C.|
|Department / Program:||Animal Sciences|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Subject(s):||Biology, Animal Physiology
Agriculture, Animal Culture and Nutrition
|Abstract:||Basic physiological rates and blood characteristics were time-course measured during three 48 hour heat-stress (35 $\pm$ 2$\sp\circ$C) periods (HS). Function variation was also monitored during a 48 hour thermoneutral recovery (25 $\pm$ 2$\sp\circ$C) period (TN).
Physiological parameters measured included: rectal temperature (Tr), respiratory rate (RR), heart rate (HR), systolic (BPS) and diastolic (BPD) blood pressure. Arterial (A) and Venous (V) blood characteristics collected via chronic catheterization included: pH (PH), PCO$\sb2$ (CO), PO$\sb2$ (O), and ionic calcium (CA). Samples of each parameter were taken prior to and at 2, 4, 6, 8, 24 and 48 hours after each temperature change. Carbonated-drinking-water (CW) was provided during the second, and tap-drinking-water (TW; TW$\sb2$) was supplied during the first and third hot exposure periods, respectively.
Physiological parameter and level of blood characteristics rapidly changed in functional rate or value, respectively, followed by a plateau at a different rate or level than during the previous temperature exposure, respectively.
RR parallels the rise in Tr during HS but recovery occurs independently of and previous to Tr into thermorecovery. RR of HS pigs did not change at elevated Tr. The pig did not shift to thermal hyperpnea as HS intensified. Tr did not generally exhibit a statistically significant increase during HS nor did APH alkaline shift. RR peaked during HS and maintained 1/2 the magnitude with CW supplementation.
Increased HR was an initial response exhibited during HS exposure. Thermally-induced bracycardia was exhibited with CW supplementation. HR decreased (P $<$.001) 24 hours into HS and continued 6 hours into TN. This may infer that CW provides a deficiency compensation.
BPS, BPD and ultimately pulse pressure declined immediately during a hot temperature episode. BPS and BPD acclimated in HS or TN with CW supplementation which implies general benefits of cardiovascular homeostasis.
ACO plateaued at a greater (P $<$.09) magnitude during HS and returned to pre-HS exposure value within 24 hours of subsequent TN with CW supplementation. ACA declined immediate to HS exposure values with CW therapy infering an improved calcium mobilization or total bioavailability mechanism.
CW provides an innovative and inexpensive source of carbonate (CO$\sb2$) and protons (H+).
|Rights Information:||Copyright 1989 Park, Thomas Frank, Jr|
|Date Available in IDEALS:||2011-05-07|
|Identifier in Online Catalog:||AAI8916294|