Influence of Growth Rate from Three to Twelve Months of Age on Reproductive Characteristics of Boars

The objective of the present study was to evaluate the influence of growth rate from 3 to 12 months of age on the onset of puberty, libido and fertility of boars

MGA Influence on Ovum Transport and Fertility in Beef Cows

Artificial insemination (A.I.) has been commercially available to beef producers for nearly 20 years. However, most beef cattlemen do not take advantage of A.I. because of the labor and management required during the long breeding season. If the breeding season could be condensed into a few days through estrus synchronization, this disadvantage could be overcome. Most methods of estrus synchronization have involved the feeding of a synthetic progestin for several days. These compounds prevent estrus and ovulation until 2 to 8 days following their withdrawal. However, reduced fertility at the first estrus following withdrawal has been a problem. It is not understood why fertility is subnormal at this estrus. The purpose of this study was to determine the effect of melengestrol acetate (MGA), a synchronizing compound, on the rate of ovum transport in the beef cow. Egg development, ovarian conditions and fertility were also observed

Increasing the Frequency of Twinning in Beef Cows

The beef cow must be maintained throughout the year to produce only one useful product, a weaner calf. If she fails to wean a calf, the costs of maintaining her must be borne by the productive members of the herd. In the United States, the estimated percent calf crop ranges from 65 to 90% with 85% suggested as average for the more productive areas of the country. This means maintaining 100 cows for every 85 calves weaned. However, the rancher normally must add replacement heifers at the rate of 15% of the cow herd each year. This means marketing 70 weaning calves per 100 cows. One potential method of improving production efficiency is to increase the number of calves per 100 cows. Twinning could be a method of reaching this goal

A Comparison of Visual Observation and KaMar Heat Detectors as a Means of Detecting Heat in Heifers

The key to any successful artificial insemination program is doing an adequate job of detecting cows in heat. Not only is heat detection difficult for the inexperienced person, it requires considerable time and labor. There are devices available on the market which are designed to reduce labor requirements associated with heat detection. One of these devices is the heatmotmt detector called KaMar® (KaMar Inc., Steamboat Springs, Colorado). The purpose of this study was to compare the KaMar patch to a person experienced in detecting yearling heifers in heat

Influence of Temporary Chemical Immobilization of Boar Spermatozoa Upon In Vitro Survival

The use of artificial insemination (AI) in swine has been restricted because of the inability to store semen. It is usually recommended that for AI use boar semen not be stored more than 48 hours. Obviously, the goal is to develop a technique whereby boar semen could be stored indefinitely such as is the case with bull semen. However, until such a technique is developed, a method of storing boar semen for a few days would be of value for promoting AI in swine

Cool White Dwarfs Revisited -- New Spectroscopy and Photometry

In this paper we present new and improved data on 38 cool white dwarfs identified by Oppenheimer et al. 2001 (OHDHS) as candidate dark halo objects. Using the high-res spectra obtained with LRIS, we measure radial velocities for 13 WDs that show an H alpha line. We show that the knowledge of RVs decreases the UV-plane velocities by only 6%. The radial velocity sample has a W-velocity dispersion of sig_W = 59 km/s--in between the values associated with the thick disk and the stellar halo. We also see indications for the presence of two populations by analyzing the velocities in the UV plane. In addition, we present CCD photometry for half of the sample, and with it recalibrate the photographic photometry of the remaining WDs. Using the new photometry in standard bands, and by applying the appropriate color-magnitude relations for H and He atmospheres, we obtain new distance estimates. New distances of the WDs that were not originally selected as halo candidates yield 13 new candidates. On average, new distances produce velocities in the UV plane that are larger by 10%, with already fast objects gaining more. Using the new data, while applying the same UV-velocity cut (94 km/s) as in OHDHS, we find a density of cool WDs of 1.7e-4 pc^-3, confirming the value of OHDHS. In addition, we derive the density as a function of the UV-velocity cutoff. The density (corrected for losses due to higher UV cuts) starts to flatten out at 150 km/s (0.4e-4 pc^-3), and is minimized (thus minimizing a possible non-halo contamination) at 190 km/s (0.3e-4 pc^-3). These densities are in a rough agreement with the estimates for the stellar halo WDs, corresponding to a factor of 1.9 and 1.4 higher values.Comment: Accepted to ApJ. New version contains some additional data. Results unchange

The Faint End Slopes Of Galaxy Luminosity Functions In The COSMOS 2-Square Degree Field

We examine the faint-end slope of the rest-frame V-band luminosity function (LF), with respect to galaxy spectral type, of field galaxies with redshift z<0.5, using a sample of 80,820 galaxies with photometric redshifts in the Cosmic Evolution Survey (COSMOS) field. For all galaxy spectral types combined, the LF slope, alpha, ranges from -1.24 to -1.12, from the lowest redshift bin to the highest. In the lowest redshift bin (0.02<z<0.1), where the magnitude limit is M(V) ~ -13, the slope ranges from ~ -1.1 for galaxies with early-type spectral energy distributions (SEDs), to ~ -1.9 for galaxies with low-extinction starburst SEDs. In each galaxy SED category (Ell, Sbc, Scd/Irr, and starburst), the faint-end slopes grow shallower with increasing redshift; in the highest redshift bin (0.4<z<0.5), the slope is ~ -0.5 and ~ -1.3 for early-types and starbursts respectively. The steepness of alpha at lower redshift could be qualitatively explained by large numbers of faint dwarf galaxies, perhaps of low surface brightness, which are not detected at higher redshifts.Comment: 24 pages including 5 figures, accepted to ApJ

An Evaluation of the Use of Dexamethasone for Inducing Parturition in the Sow

The objective of the study was to evaluate the use of dexamethasone for inducing and controlling the time of parturition in the sow

Exploring the multi-humped fission barrier of 238U via sub-barrier photofission

The photofission cross-section of 238U was measured at sub-barrier energies as a function of the gamma-ray energy using, for the first time, a monochromatic, high-brilliance, Compton-backscattered gamma-ray beam. The experiment was performed at the High Intensity gamma-ray Source (HIgS) facility at beam energies between E=4.7 MeV and 6.0 MeV and with ~3% energy resolution. Indications of transmission resonances have been observed at gamma-ray beam energies of E=5.1 MeV and 5.6 MeV with moderate amplitudes. The triple-humped fission barrier parameters of 238U have been determined by fitting EMPIRE-3.1 nuclear reaction code calculations to the experimental photofission cross section.Comment: 5 pages, 3 figure