1,073 research outputs found
Daily or weekly rotational feeding of Bovatec®- and Rumensin®/Tylan® to cattle on a steam-flaked corn finishing ration
One hundred sixty-five crossbred steers averaging 823 lb were utilized to evaluate the daily or weekly rotational feeding of ionophores. Treatments were (g/ton of feed, 90% dry basis): 1) Bovatec (B; 30), 2) Rumensin plus Tylan (RT; 25 and 10, respectively), 3) treatments one and two in a daily rotation (D), and 4) treatments one and two in a weekly rotation (W). Steers fed RT consumed less (P\u3c.05) dry matter than B, D\u3eor W steers. No differences (P\u3e.15) in daily gain were observed, suggesting that the increased consumption by B, D) and W steers was accompanied by an al teration in passage rate and/or other kinetics of digestion, such that additional consumption was poorly utilized. Thus, RT steers gained 3.9% more efficiently (P=.06) than B steers and numerically more efficiently than D or W steers. No differences were observed among treatments for carcass quality or yield. Performance of D and W steers did not differ from that predicted by the performance of steers fed B and RT fed separately, indicating no synergism from alternate feeding of ionophores in this study
Utilization of dried bakery product by finishing beef steers
One hundred forty-four medium-framed
crossbred steers averaging 857 lb were used to
evaluate steer performance and determine net
energy (NE) values of finishing diets that
included dried bakery product (DBP). DBP replaced
corn in the control diet at 15 or 30% of
dietary DM. DM intake was depressed 6.5%
by inclusion of 30% DBP. No differences in
daily gain (P>.3) or feed efficiency (P>.9)
were observed by replacing corn with DBP.
Dietary values of NEm and NEg, calculated
from animal performance, were not affected
(P>.7) by the inclusion of DBP. Kidney,
pelvic, and heart fat (KPH) (P<.05) and 12th
rib fat thickness (P<.1) were increased
linearly with inclusion of DBP, whereas other
carcass characteristics were unaffected. These
data indicate the DBP (10% rice hulls included)
has an energy value similar to that of corn
grain, although the optimal inclusion level of
DBP appears to be below 30% of dietary DM
Optimal urea level in corn-based finishing diets containing alfalfa as the roughage source
One hundred medium-growth potential,
crossbred yearling steers (766 lb) were used to
identify the optimal level of urea in finishing
diets, based on growth and carcass traits. The
corn-base d diets had no urea o r contained .35,
.70, 1.05, or 1.40% urea (dry matter basis) and
no other supplemental protein. Alfalfa hay
(10% of DM) was the roughage source and
contained 16% crude protein. Feed efficiency
and gain were improved by .35% urea, with
little improvement from higher additions.
Regression analysis indicated that the optimal
level of urea for gain and feed efficiency was
.5% of dietary dry matter. Hot carcass weight
and dressing percentage responded
quadratically, being highest for steers receiving
.7 and 1.05% urea. Fat thickness and yield
grade responded cubically to the addition of
urea; these traits were also highest for steers receiving
.7 and 1.05% urea. Loineye area
decreased linearly with increased urea in the
diet. Marbling scores and KPH fat were
unaffected by urea addition. The increased
growth, carcass weight, and finish, with no
improvements in loineye area, indicate that urea
enhance d diet digestibility but did not increase
metabolizable protein supply. Optimal urea
levels (.5%) were less than those previously
indicate d for diets containing prairie hay as the
roughage source (.9%), suggesting that alfalfa
may supply a portion of the rumen degradable
nitrogen requirement when utilized as a source
of roughage in high grain diets
Comparison of Synovex-S® and steer-oid® in finishing yearling steers
Synovex-S (SS) and STEER-oid (SO) were
compared in a 122-d finishing study. No
differences were observed over the entire study
for animal performance or carcass traits.
However, in the final period (d 91-122), steers
implanted with SO gained 8.4% faster (P=.17)
and 8.7% more efficiently (P=.10) than steers
implanted with SS, suggesting that estradiol
payout in this period was less diminished for SO
implants. The importance of this finding is
unknown, because it is generally recommended
that steers fed for longer periods of time be
reimplanted midway through the finishing period
to maintain maximal implant response
Implant strategies for finishing calves
Two hundred-sixteen Angus and Angus-cross
steer calves (690 lb) were used in a 129-
day finishing study to evaluate different implant
strategies, including an experimental new
implant for feedlot cattle that contains 28 mg of
estradiol benzoate and 200 mg of trenbolone
acetate (EBTBA). Treatments were 1)
nonimplanted control, 2) implanted and
reimplanted with Synovex-Sfi, 3) single initial
implant with EBTBA, 4) single initial implant
with Revalor-Sfi, 5) implanted with Synovex-S
and reimplanted with EBTBA, and 6) implanted
and reimplanted with EBTBA. Initial implants
and reimplants were administered on day 0 and
63, respectively. All implant treatments
increased feed intake, slaughter and carcass
weights, and rate and efficiency of gain.
Compared with other implant treatments, the
use of EBTBA as a reimplant treatment (trts 5
and 6) resulted in improved (P<.08) rate and
efficiency of gain and heavier carcass weights
(P<.07). However, only 58.3% of cattle in trts
5 and 6 graded Choice vs. 86.1% for controls
and 80.6% for steers implanted twice with
Synovex-S (P<.07). Carcasses were more
masculine (P<.07) for steers in trts 5 and 6 than
for nonimplanted controls, steers implanted with
Revalor-S, and steers implanted twice with
Synovex-S. Performance of steers implanted
once with EBTBA did not differ from that of
steers implanted once with Revalor-S or twice
with Synovex-S, but carcasses were more
masculine (P<.07) for EBTBA vs. Revalor-S
steers. Implant treatment
did not affect meat tenderness, as
measured by Warner-Bratzler shear force
determinations. Single EBTBA or Revalor-S
implants resulted in performance and carcass
traits similar to those resulting from implanting
twice with Synovex-S
Puberty and breeding performance of beef heifers developed at different rates of gain
Crossbred heifers (546 lb initial body
weight) were developed in drylot and limit-fed
a corn, corn silage diet to gain .5 (n =
14), 1.0 (n = 15), 1.5 (n = 14), or 2.0 lb/d (n
= 15) from Dec. 7, 1992 until the onset of the
breeding season, May 3, 1993. Actual daily
gains averaged 1.0, 1.4, 1.8, and 2.1 lb/d,
respectively. Age at puberty was not affected
by feeding treatment. At the onset of the
breeding season, nutritional treatment had a
linear effect on body condition score, ribeye
fat thickness (both P<.01), and reproductive
tract score (P<.05), all increasing with
increasing rate of gain. Nutritional treatment
had a quadratic effect on pelvic area (P<.05),
which averaged 190.6, 201.6, 206.5, and
205.3 cm2 for heifers fed to gain .5, 1.0, 1.5,
and 2.0 lb/d, respectively. At the conclusion
of the development period, estrus was
synchronized, and heifers were inseminated
artificially at estrus for 45 days and, if open,
mated naturally for another 17 d. Overall
pregnancy rates were similar among heifers
fed to gain .5, 1.0, and 1.5 lb/d (92.9, 93.3,
and 92.9%, respectively), and all tended to be
greater (P<.09) than the rate for heifers fed to
gain 2.0 lb/d (66.7%). In summary, NRC
recommendations underestimated gain of
limit-fed heifers at lower predicted rates of
gain. Thus, even though heifers fed to gain
only .5 lb/d had lower body condition scores
and reproductive tract scores at the onset of
the breeding season, their actual body weight
gains (1.0 lb/d) were sufficient for normal
onset of puberty and subsequent conception.
In addition, heifers fed to achieve relatively
high rates of gain (2.0 lb/d) during development
may have had impaired fertility
Increasing levels of grain supplementation for intensive-early stocked steers: three-year summary
During the initial 3 years of a 4-year
experiment, average daily gain tended to
increase in direct proportion to increasing levels
of grain sorghum supplementation (2.3, 2.5 and
2.7 lb gain per day for the control and 2 and 4
lb supplement per day, respectively). The
amount of grass remaining in the pastures at the
end of the growing season (October 1) was
greater in each of the 3 years when cattle were
supplemented at 4 lb/day. During the 2 years
(1989 and 1990) that feedlot performance was
monitored, level of supplementation for grazing
steers did not influence subsequent feedlot gain
or efficiency
Supplemental chromium and revaccination effects on performance and health of newly weaned calves
Two trials were conducted to evaluate the effects of chromium (Cr) supplementation (4 mg/hd/day in a yeast form) or no supplementation, with or without revaccination with a modified live viral vaccine at 9 days postweaning o n performance, health, and ability to withstand an IBR challenge infection. In Trial 1, Cr supplementation had no effect on performance of newly weaned calves in a 28-day receiving study, but reduced the incidence of respiratory disease by 37%. Revaccinati on depressed dry matter intake and had no effect on animal health. In trial 2, blood plasma levels of cortisol and ACTH (stress hormones ) were measured at 6 and 26 days postweaning. Cortisol levels were unaffected by treatment or by time after weaning. Plasma ACTH conc e ntrations were lower at 26 vs 6 days postweaning, and were reduced at 26 days by revaccination. Despite some slight differences in rectal temperature, treatment did not appear to affect the animals\u27 ability to withstand a live IBR challenge. We concluded that supplemental Cr was beneficial in reducing the incidence of bovine respiratory disease, although mediation of stress hormones was not involved. Revaccination of newly weaned calves with a modified live viral vaccine showed no performance or health benefit
A Survey of z>5.7 Quasars in the Sloan Digital Sky Survey IV: Discovery of Seven Additional Quasars
We present the discovery of seven quasars at z>5.7, selected from ~2000 deg^2
of multicolor imaging data of the Sloan Digital Sky Survey (SDSS). The new
quasars have redshifts z from 5.79 to 6.13. Five are selected as part of a
complete flux-limited sample in the SDSS Northern Galactic Cap; two have larger
photometric errors and are not part of the complete sample. One of the new
quasars, SDSS J1335+3533 (z=5.93), exhibits no emission lines; the 3-sigma
limit on the rest-frame equivalent width of Ly alpha+NV line is 5 A. It is the
highest redshift lineless quasar known, and could be a gravitational lensed
galaxy, a BL Lac object or a new type of quasar. Two new z>6 quasars, SDSS
1250+3130 (z=6.13) and SDSS J1137+3549 (z=6.01), show deep Gunn-Peterson
absorption gaps in Ly alpha. These gaps are narrower the complete Gunn-Peterson
absorption troughs observed among quasars at z>6.2 and do not have complete Ly
beta absorption.Comment: AJ in press, 16 pages, 3 figure
Optimization of the Observing Cadence for the Rubin Observatory Legacy Survey of Space and Time: A Pioneering Process of Community-focused Experimental Design
© 2021. The Author(s). Published by the American Astronomical Society. This work may be used under the terms of the Creative Commons Attribution 4.0 licence. https://creativecommons.org/licenses/by/4.0/Vera C. Rubin Observatory is a ground-based astronomical facility under construction, a joint project of the National Science Foundation and the U.S. Department of Energy, designed to conduct a multipurpose 10 yr optical survey of the Southern Hemisphere sky: the Legacy Survey of Space and Time. Significant flexibility in survey strategy remains within the constraints imposed by the core science goals of probing dark energy and dark matter, cataloging the solar system, exploring the transient optical sky, and mapping the Milky Way. The survey’s massive data throughput will be transformational for many other astrophysics domains and Rubin’s data access policy sets the stage for a huge community of potential users. To ensure that the survey science potential is maximized while serving as broad a community as possible, Rubin Observatory has involved the scientific community at large in the process of setting and refining the details of the observing strategy. The motivation, history, and decision-making process of this strategy optimization are detailed in this paper, giving context to the science-driven proposals and recommendations for the survey strategy included in this Focus Issue.Peer reviewedFinal Published versio
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