Confinement and social isolation as possible stressors on horses /
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| Format: | Thesis Book |
| Language: | English |
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[College Station, Tex.] :
[Texas A&M University],
[1990]
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| Subjects: |
| Abstract: | ABSTRACT: Thirty six embryo transfer recipient mares, blocked by age and temperament, were assigned to one of three housing treatment groups: Pasture (P); Confinement stalls (C), allowing social contact; and Isolation stalls (I), allowing no contact with conspecifics. Forty-eight h post placement on treatment, the animals were observed in situ for 1 h and behaviors were recorded. After in situ observations were completed, mares were injected intradermally with a solution of .1 mg phytohemagglutinin (PHA) in .1 ml saline in one side of the neck. After 65 h on treatment, each mare was fitted with a jugular catheter from which a blood sample was drawn and analyzed for plasma concentrations of thyroid hormones, complete blood cell counts, and differential leukocyte counts. The mares were allowed to stand for 1 h with the catheter in place, during which time the PHA response measured. After 1 h, a second sample was drawn and ACTH was administered. Blood samples were drawn 20, 40, 60, 80, 100, 120, 150, 180, and 210 min post ACTH administration. Samples were later assayed for plasma cortisol concentrations in order to determine adrenal function (AF). After the last blood sample was drawn, the mares were subjected to a 15 min open field test in a 23 x 23 m pen and their behaviors recorded. Isolation mares traveled farther in the open-field test, trotted more, and stood less. Behavioral time budget differences were observed for treatments. A trend in AF was observed, with P mares tending to have the lowest AF and I mares the highest. No differences were seen for concentrations of thyroxine and triiodothyronine, although for C and I mares the concentrations of these hormones were higher than the normal values reported in the literature. Concentrations of 3,3',5' triiodothyronine were higher in I mares than in C and P mares. Blood hemoglobin was elevated for I mares. Reaction to PHA injection was higher for C and I mares than for P mares. Behavioral and physiological data suggest that C and I mares exhibited evidence of stress reactions due to treatment. |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Animal Science." "Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of Master of Science May 1990". |
| Physical Description: | xi, 122 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |