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United States Department of Agriculture

Agricultural Research Service

Title: Functional test of the hypothalamic-pituitary-adrenal axis of sows housed in various environments

Author
item Lay, Jr, Donald

Submitted to: International Society of Applied Ethology
Publication Type: Abstract Only
Publication Acceptance Date: April 25, 2007
Publication Date: July 31, 2007
Citation: Lay Jr, D.C. 2007. Functional test of the hypothalamic-pituitary-adrenal axis of sows housed in various environments. International Society of Applied Ethology. Proceedings, p. 212.

Technical Abstract: The objective of this study was to assess the behavioral state of sows housed in various housing systems, and determine if the regulation of their hypothalamic-pituitary-adrenal axis had been altered. In Experiment 1, 33 sows were housed in either gestation stalls, group housed with no bedding, or group housed with bedding. A 10 mL blood sample was collected at 1800 h. Immediately following blood collection, 2 mg of dexamethasone was administered i.v. Twelve hours later, a second blood sample was collected. In Experiment 2, all 14 sows were stall housed. Behavioral data was collected weekly on 3 separate days. At 0830, 1 h after sows were fed. Behavioral assessments were conducted to determine the incidence and type of stereotypic behavior that each sow performed. Dexamathasone was administered as in Experiment 1 with blood collection at 2000 h and 0800 h the following morning. Baseline concentrations of plasma cortisol varied among treatments in Experement 1, with stall housed sows having a greater baseline (P < .05) than grouped sows without bedding. Sows in all three treatments showed a similar decrease in plasma cortisol. Ten sows from Experiment 2 performed stereotypic behaviors during 50 % or more of the observations. Dexamethasone suppressed plasma cortisol in 11 sows who exhibited base concentrations of 37.4 ± 4.9 ng/mL which were decreased to 9.9 ± 1.2 ng/mL by 12 h later. Three sows proved to be resistant to the dexamethasone. These sows exhibited base concentrations of 44.6 ± 14.7 ng/mL, which increased to 57.8 ± 13.4 ng/mL by 12 h later. The incidence of oral stereotypic behaviors were not associated with suppression of cortisol (P > .10). Sows were responsive to the suppression of cortisol by dexamethasone. Some sows were not responsive, but this characteristic does not appear to be related to the performance of stereotypic behavior.

Last Modified: 10/23/2014
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