Alfalfa accumulates phytoestrogens and when ingested binds the estrogen
receptor and induces morphological changes similar to endogenous estrogens. The
objective of this study is to evaluate morphological changes in uteri, vulva, and
teats of ovariectomized prepubertal ewe lambs. Eighteen prepubertal ewe lambs
were ovariectomized in November 2000 and fed nonestrogenic hay until May 2001.
In May, ewes were fed bentgrass straw and cottonseed meal. On day 0 of a 12-day
feed trial, ewes were assigned randomly to three treatments (n=6 in each
treatment): Estradiol, Control, and Alfalfa. Estradiol treated ewes were fed
bentgrass straw and cottonseed meal ad libitum, plus receiving a daily injection of
10 mg estradiol-17�� suspended in corn oil. Control ewes were fed bentgrass straw
and cottonseed meal ad libitum and received a daily injection of corn oil vehicle.
Alfalfa ewes were fed alfalfa ad libitum and received a daily injection of corn oil
vehicle. Three blinded observers assigned each ewe a subjective score ranging
from 1 (no change) to 4 (significant change) for vulva and teat morphology on
Days 0, 1, 3, 5, 7, 9 and 12. Teat length and circumference were measured on Days
1, 7 and 12. Ewes were slaughtered on Day 13, uteri were weighed, and a cross-section
was collected from each uterine horn. Cross-sections were fixed in Lillie's
Neutral Buffered Formalin and embedded in paraffin wax, sectioned at 4-5 ��m, and
stained with hematoxylin and eosin. An ocular micrometer was used to measure
luminal epithelial cell height. Estradiol treated ewes had heavier (p<0.05) uterine
weights and greater (p<0.05) uterine luminal epithelial cell height than that of ewes
fed alfalfa or control ewes. Uterine weights and uterine luminal epithelial cell
height were greater (p<0.05) in alfalfa fed ewes than control ewes. Vulva scores
for estradiol treated ewes were higher than those of control ewes (p<0.05). Alfalfa
fed ewes had numerically higher vulva scores than control ewes but the difference
was not significant statistically (p>0.05). Teat scores or measurements showed no
differences (p>0.05) among treatments. Ewes exhibited slight changes in vulva
scores due to treatment, but the most noted effects were observed in uterine growth.
This research suggests that uterine weight and uterine luminal epithelial cell height
are sensitive to the estrogenic activity of alfalfa and estradiol-17 resulting in
morphological changes in estrogen target tissues in the prepubertal ewe lamb. / Graduation date: 2003
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/31127 |
| Date | 15 July 2002 |
| Creators | Sexson, Clinton |
| Contributors | Males, James R. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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