Effect of in utero maternal stress on the calf's response to later stressors /
Twenty-five pregnant Brahman heifers were injected with either: 0 (saline), .125, .25,.5, or I IU ACTH per kg BW. After the dose response to ACTH was determined, 75 pregnant Brahman cows were randon-Ay assigned to treatment groups: 1) transported in a stock trailer for 24.2 km, unloaded at a second...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1995.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=742161761&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | Twenty-five pregnant Brahman heifers were injected with either: 0 (saline), .125, .25,.5, or I IU ACTH per kg BW. After the dose response to ACTH was determined, 75 pregnant Brahman cows were randon-Ay assigned to treatment groups: 1) transported in a stock trailer for 24.2 km, unloaded at a second farm and penned for I h then returned to the original farm (TRANS)- 2) injected with ACTR I IIJ/kg of BW (ACTH); or 3) merely walked through the handling facilities (SHAM). Treatments were repeated at 60, 80, 1 00, 120, and 140 d of gestation. Six TRANS and six SHAM calves were delivered by Cesarian-section on d 266 of gestation and sacrificed. Forty-two, naturafly-bom calves were either restrained (n = 21) or restrained and given ACTH (. 125 IU/kg of BW, n = 21) at 10- and 150 d of age. At 180 d of age, these calves were either hot-iron branded (n = 21) or injected with a bolus of cortisol (6.7 ng/kg of BW, n = 21) to determine clearance rate. Results for the dose response of ACTH indicated that the greater the dose of ACTR the greater was the integrated area (P = .0002). However, peak plasma cortisol in response to the four doses of ACTH did not dfffer (P = .5). Organs and plasma collected from Ceasarian-section calves found that TRANS calves had heavier pituitary glands (P .008) and body weight (P =.08) than SHAM calves. Between the TRANS and SHAM calves, the weight of the adrenal glands did not differ (P = .2) nor did the ratio of medulla to cortex (P = .6). Of the calves that were born naturally, ACTU calves weighed more than the SHAM calves but not the TRANS calves (P =.08). No differences were detected between treatments for calves being branded (P = . 1). Cortisol clearance rate was slower for the TRANS calves than for the SHAM calves (P = . 0 1), but not the ACTH calves (P = . 1). Exposing cows to repeated transportation stress during gestation appears to alter their calves' morphology and physiological response to stress. |
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| Item Description: | Vita. "Major Subject: Animal Science". |
| Physical Description: | ix, 64 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references. |