| dc.description.abstract | Linseed meal (LSM) was fed to ovariectomized ewes exposed to estradiol 17-ß (E2)
implants over time, and LSM was supplemented to beef cows during late gestation and
early lactation to evaluate the estrogenic potential of the phytoestrogen secoisolariciresinol
diglycoside (SDG) found in LSM. Forty-eight ovariectomized ewes were fed a diet
containing 12.5% LSM for 0, 1, 7, or 14 d and implanted with estradiol-17ß (E2) for 0, 6,
or 24 h before tissue collection. Uterine cellular proliferation, vascularity, and the
expression of the angiogenic factors and their receptors were recorded. There was an
interaction of LSM and E2 on uterine mass (P = 0.05). At 24 h of E2 exposure,
proliferation was reduced (P < 0.001) when ewes were fed for 14 d compared to being fed
0 or 1 days. There was a LSM x E2 interaction (P ≤ 0.03) on VEGF receptor-2 (KDR) and
hasicfihrohlast growth factor receptor (FGFR2) decreasing by 24 h E2 exposure.
Exposure of LSM and E2 may impact the estrogenic response of sensitive tissue.
Two studies were conducted to examine the effects of supplementing beef cows
with LSM during late gestation or early lactation on calf growth and development. In
Experiment 1, multiparous cows received either LSM or a control (CON) supplement
(approximately 10% diet dry matter) for the last 60 d of gestation. Offspring weights,
ADG, heifer age at puberty, conception percentage and steer carcass characteristics were
recorded. In Experiment 2, multiparous cows received LSM or CON supplements
(approximately 10% diet dry matter) during the first 60 d of lactation, and only heifer calf
development performance was observed and recorded. Heifer calf weight, average daily
gain, and attainment of puberty were assessed. For both experiments, birth weight, weaning
weight and ADG were not affected (P > 0.31) by LSM supplementation. While final body
weights were heavier (P = 0.04) for steer calves in Experiment 1, there was no effect (P =
0.09) of supplementation on carcass characteristics. In Experiment 1 and 2, attainment of
puberty in heifer calves was not influenced (P > 0.58) by supplement type. Linseed meal
supplementation during late gestation or early lactation does not appear to have a negative
impact on calf growth, onset of puberty in heifer calves, or steer carcass quality,
implicating that it may make a good supplement choice in cattle. | en_US |
