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Evaluation of ultrasound and other sources of information to predict beef carcass traits and final carcass valueDean, Dustin Tyler 16 August 2006 (has links)
Purebred Beefmaster steers (n = 160) from five owners were fed at a commercial
feedlot in South Texas beginning in November of 2004; 68 steers possessed pedigree
information. Beginning in mid-November, steers were individually weighed and
evaluated for ultrasound body composition at 56-d intervals by a certified technician.
Feeder calf frame (FRM) and muscle (MUS) scores were assigned at initial ultrasound
evaluation. Steers were fed and marketed through a lean-based, branded beef program
and were harvested in two groups in May and June of 2005 at a commercial beef plant.
Analyses were conducted to investigate the ability to predict carcass traits from the
different sources of information available on these cattle. Evaluation of carcass traits
were investigated using four sets of independent variables referred to as sources A, B, C,
or D and ultrasound scan session (1 Â 4). An analysis included initial weight at first scan
session (IWT), FRM and MUS as independent variables through GLM procedures. B
analyses utilized ultrasound measures of the longissimus area, intramuscular fat, fat
thickness, rump fat, and gluteus medius depth along with IWT as independent variables.
Multiple regression was performed on each carcass trait using IWT and ultrasound traits
at each scan session. MallowÂs CP was used to select a model that best described each carcass trait. C analyses (GLM) utilized variables from A and B analyses combined plus
ranch. D analyses (GLM) included variables from C analyses plus sire nested within
ranch. Respective R-square values (scan 1 Â 4) for marbling score were .02, .04, .05, and
.10 using A information, .14, .17, .42, and .54, using B information, .35, .35, .47, and .55
using C information, and .56, .59, .65, and .76 using D information. R-square values
ranged from .34 to .86 for carcass weight, .11 to .77 for fat thickness, .06 to .82 for ribeye
area, and .10 to .81 for yield grade. Ultrasound data obtained closer to harvest and
increasing amount of data related to genetic and management background showed
increased R-square values, but may be best utilized in conjunction with one another to
predict carcass traits and final carcass value.
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Synchronization of follicular wave emergence, luteal regression, and ovulation for fixed-time artificial insemination in beef cows and heifersStutts, Kyle Jeffrey 30 October 2006 (has links)
Two experiments tested the efficacy of gonadotropin-releasing hormone
(GnRH) or estradiol cypionate (ECP) administration in combination with
controlled internal drug release (CIDR) inserts on pregnancy rate to fixed-time
artificial insemination (FTAI) in beef heifers. In the first experiment, heifers in the
two ECP groups received ECP in conjunction with the CIDR insert. The CIDR
insert was removed and PGF was administered on either d 7 or 9. Heifers
received ECP 24 h after CIDR removal and were inseminated 30 h after ECP.
Heifers in the two GnRH groups received GnRH in conjunction with the CIDR
insert. Heifers received PGF on either d 6 or 7, and the CIDR insert was
removed on d 7. Heifers were inseminated and received GnRH 48 h after CIDR
removal. Pregnancy rates to FTAI were higher for heifers treated with GnRH.
Pregnancy rate to FTAI was highest for heifers in the GnRH group that received
PGF on d 6 and was lowest for the group that received ECP in combination with
a 7-d CIDR insert. In the second experiment, heifers received GnRH in conjunction with the
CIDR insert. CIDR inserts were removed and PGF was administered on d 7.
Heifers were inseminated 60 h later, with one group receiving GnRH at
insemination. Pregnancy rate to FTAI was higher for heifers that received GnRH
at insemination.
The final experiment tested the efficacy of estradiol 17_ (E17) or GnRH in
combination with a CIDR insert on pregnancy rate to FTAI in Brahman cows.
Either E17 or GnRH was administered in conjunction with the CIDR insert.
CIDR inserts were removed on d 7. Cows in the GnRH group received PGF on
d 6 and GnRH at insemination which occurred 48 h after CIDR removal. Cows
in the E17 group received PGF on d 7, E17 24 h later, and were inseminated 30
h after E17 administration. Pregnancy rate to FTAI was higher for cows treated
with E17.
These data indicate acceptable pregnancy rates were obtained when the
CIDR insert was combined with either GnRH in beef heifers or with E17 in
Brahman cows.
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Comparison of buffered grazing systems for beef cattleWolfe, Charles R., January 1900 (has links)
Thesis (M.S.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains viii, 52 p. : ill. Vita. Includes abstract. Includes bibliographical references (p. 36-39).
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Influence of mass of ruminal contents on voluntary intake and digesta passage of a concentrate and a forage dietWhetsell, Marcela. January 1900 (has links)
Thesis (Ph. D.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains vi, 123 p. Includes abstract. Includes bibliographical references.
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Induction of cycling status and effect of follicle size on fertility in postpartum beef cowsPerry, George A. January 2003 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 162-201). Also available on the Internet.
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Effect of concentrations of progesterone on follicular development and fertility in beef cowsCandler, Jason B. January 2001 (has links)
Thesis (M.S.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains vi, 44 p. : ill. Vita. Includes abstract. Includes bibliographical references (p. 35-43).
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Profitability and business risk of fall versus spring calving in WyomingStrauch, Brian A. January 2008 (has links)
Thesis (M.S.)--University of Wyoming, 2008. / Title from PDF title page (viewed on Mar. 4, 2010). Includes bibliographical references (p. 94-96).
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An economic analysis of pasture-raised beef systems in AppalachiaEvans, Jason R. January 2003 (has links)
Thesis (M.S.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains vi, 163 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 132-136).
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Induction of cycling status and effect of follicle size on fertility in postpartum beef cows /Perry, George A. January 2003 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 162-201). Also available on the Internet.
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Factors influencing the incidence of dystocia in beef heifers /Norman, Scott T. January 2002 (has links) (PDF)
Thesis (Ph. D.)--University of Queensland, 2002. / Includes bibliographical references.
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