2,126 research outputs found
Effects of Bull Exposure and Gonadotropin Releasing Hormone on Postpartum Interval and Fertility in Beef Cowsa
Spring calving beef cows were utilized in a study to determine the effects of bull exposure (BE) and Gonadotropin Releasing Hormone (GnRH) administration on return to estrus and reproductive efficiency. Cows were either exposed to an epididectomized bull soon after calving until the breeding season or not exposed to bulls (NE). All cows were synchronized with Synchro-Mate B (SMB). One-half of the BE and NE cows were implanted with GnRH at SMB implant removal in 1987 or given an injection of GnRH at breeding in 1988. Each year, 20 cows were bled hourly for 80 consecutive hours after SMB removal. There was no difference (P\u3e.05) in days from calving to first estrus, calving date, number of cows cycling before breeding or conception rate to the synchronized estrus between BE or NE cow groups. In 1987 GnRH implants reduced (P\u3c.05) the time from SMB removal to the pre-ovulatory LH peak by 23.5 hours. However, there was no difference (P\u3e.05) in LH peak levels, duration of Luteinizing Hormone (LH) peak or conception rate. Bull exposure and GnRH implants had little effect on the interval from calving to first estrus or reproductive performance
Effects of Bull Exposure on Post-partum Interval and Reproductive Performance in Beef Cows
Spring calving beef cows were utilized to study the effect of bull exposure early postpartum on return to estrus and fertility. In the spring of 1985 and 1986, cows were randomly exposed to epididectomized bulls 3 to 7 days after calving until beginning of the breeding season or not exposed to bulls. Cows were observed for estrus twice daily beginning approximately 4 weeks after the start of calving until synchronization. I n 1986, blood samples were collected weekly by jugular venipuncture during heat detection and serum progesterone concentrations were determined. ALL cows were synchronized with Synchro-Mate B and inseminated 48 hours after implant removal. Calves were removed for 48 hours following implant removal. Each year a group of cows was selected from the two treatment groups and cannulated at estrus following Synchro-Mate B implant removal. Blood samples were collected at 15-minute intervals for 2 hours and every 2 hours for 46 hours for determination of luteinizing hormone concentration. Bull exposed cows had a shorter (Pa.09) interval to first estrus in 1985 and there was no difference (P\u3e.05) in 1986. The percentage exhibiting estrus prior to synchronization was greater (P\u3e.01) for bull exposed than nonexposed in 1985 and there was no difference (P\u3e.05) in 1986. There was no difference (P\u3e.05) in conception rates to the timed insemination in 1985 and 1986 and the total percentage pregnant did not differ (P\u3e.05) in either year. Bull exposure may reduce the interval from calving to first estrus and increase the percentage cycling prior to breeding, but conception rates are not influenced
The Bailey Point Region and Other Muskox Refugia in the Canadian Arctic: A Short Review
The muskox (Ovibos moschatus) is widely distributed over much of arctic Canada but only at a few locations do their densities remain high and populations relatively stable. These refugia constitute the most favourable muskox ranges in the Canadian Arctic Archipelago .... Refugia for muskoxen in the High Arctic include lowlands on eastern Axel Heiberg Island in the Mokka Fiord region, the lowlands of northeastern Devon Island, and the Bailey Point region of Melville Island .... All of those regions historically have supported high densities of muskoxen from time to time but the Bailey Point region must be considered the best habitat for muskoxen in the Canadian High Arctic. ..
Precision Primordial He Measurement with CMB Experiments
Big bang nucleosynthesis (BBN) and the cosmic microwave background (CMB) are
two major pillars of cosmology. Standard BBN accurately predicts the primordial
light element abundances (He, D, He and Li), depending on one
parameter, the baryon density. Light element observations are used as a
baryometers. The CMB anisotropies also contain information about the content of
the universe which allows an important consistency check on the Big Bang model.
In addition CMB observations now have sufficient accuracy to not only determine
the total baryon density, but also resolve its principal constituents, H and
He. We present a global analysis of all recent CMB data, with special
emphasis on the concordance with BBN theory and light element observations. We
find and
(fraction of baryon mass as He) using CMB data alone, in agreement with
He abundance observations. With this concordance established we show that
the inclusion of BBN theory priors significantly reduces the volume of
parameter space. In this case, we find
and . We also find that the inclusion of deuterium
abundance observations reduces the and ranges by a factor
of 2. Further light element observations and CMB anisotropy experiments
will refine this concordance and sharpen BBN and the CMB as tools for precision
cosmology.Comment: 7 pages, 3 color figures made minor changes to bring inline with
journal versio
Towards a formalism for mapping the spacetimes of massive compact objects: Bumpy black holes and their orbits
Observations have established that extremely compact, massive objects are
common in the universe. It is generally accepted that these objects are black
holes. As observations improve, it becomes possible to test this hypothesis in
ever greater detail. In particular, it is or will be possible to measure the
properties of orbits deep in the strong field of a black hole candidate (using
x-ray timing or with gravitational-waves) and to test whether they have the
characteristics of black hole orbits in general relativity. Such measurements
can be used to map the spacetime of a massive compact object, testing whether
the object's multipoles satisfy the strict constraints of the black hole
hypothesis. Such a test requires that we compare against objects with the
``wrong'' multipole structure. In this paper, we present tools for constructing
bumpy black holes: objects that are almost black holes, but that have some
multipoles with the wrong value. The spacetimes which we present are good deep
into the strong field of the object -- we do not use a large r expansion,
except to make contact with weak field intuition. Also, our spacetimes reduce
to the black hole spacetimes of general relativity when the ``bumpiness'' is
set to zero. We propose bumpy black holes as the foundation for a null
experiment: if black hole candidates are the black holes of general relativity,
their bumpiness should be zero. By comparing orbits in a bumpy spacetime with
those of an astrophysical source, observations should be able to test this
hypothesis, stringently testing whether they are the black holes of general
relativity. (Abridged)Comment: 16 pages + 2 appendices + 3 figures. Submitted to PR
Effects of Bull Exposure on Postpartum Intervals and Reproductive Performance in Beef Cows: A progress Report
The effects of bull exposure on time from calving until estrus, conception rates and calving interval were studied for mature beef cows. In the spring of I985 and 1986, cows were randomly allotted to one of two treatment groups. Cows were exposed to vasectomized bulls after calving until breeding or no bull exposure. Cows were heat detected twice daily and blood samples were collected weekly to determine progesterone levels. Heat detection data and progesterone levels indicated onset of estrous cycles occurred earlier in bull exposed cows than non-exposed cows. Conception rates to a timed insemination were not different between the two groups. Bull exposed cows tended t o calve earlier
Effectiveness of Albendazole Against Parasites and Cow and Calf Performance
Albendazole was utilized in drench and feed additive form to determine its effectiveness against parasite control, cow weight and conception rate and calf weaning weights. Fecal oocyte number was decreased by administration of Albendazole. Calf weaning weights from treated cows were heavier the first two years (14.5 lb for heifers and 10.5 lb for bulls) but decreased the third year (13 lb and 6 lb for heifers and bulls, respectively). Conception rates were similar between the two groups, with the only difference occurring the third year when control cows had a higher conception rate from the second AI than treated cows
A Proposed Test of Charge Symmetry in Decay
The semi-leptonic decays of offer a vehicle for observing charge
symmetry-breaking. The effect is expected to be about 6\%, enhanced due to the
replacement of two u quarks by d quarks. We propose that present experimental
data be improved to search for this effect.Comment: 6 pages, submitted to Physical Review D, Brief Reports, Report #
DOE/ER/40427-14-N9
Nonlocal Effects and Shrinkage of the Vortex Core Radius in YNi2B2C Probed by muSR
The magnetic field distribution in the vortex state of YNi2B2C has been
probed by muon spin rotation (muSR). The analysis based on the London model
with nonlocal corrections shows that the vortex lattice has changed from
hexagonal to square with increasing magnetic field H. At low fields the vortex
core radius, rho_v(H), decreases with increasing H much steeper than what is
expected from the sqrt(H) behavior of the Sommerfeld constant gamma(H),
strongly suggesting that the anomaly in gamma(H) primarily arises from the
quasiparticle excitations outside the vortex cores.Comment: 4 pages, 4 figures, submitted to Phys. Rev.
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