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

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

The effect of alloy content on the microstructure of as-deposited weldmetal in 9Cr-based ferrous weldments

The more widespread use of 9Cr-1Mo-based steels (modified and un-modified) is limited, in part, by a lack of understanding of the welding behaviour of this class of materials. A series of weldments, based on modified 9Cr-1Mo alloy steels, with varying Si and Mn contents was investigated using transmission electron microscopy (TEM). All as-deposited samples were found to consist of laths of heavily dislocated martensite separated by an interlath phase. Addition of Si was found to increase the amount of retained austenite (γ) present in the interlath region, whilst increasing Mn content promoted carbide formation. At high levels of both additions, a banded structure containing both phases was formed. These additions had little effect on the carbides (M23C6 type) present within the laths

The Battle of the Somme 1916 The experience of the 13 (Service) Battalion of the York and Lancaster Regiment

SIGLEAvailable from British Library Lending Division - LD:8255.782(POL--6/77) / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Automatic and Interactive Correlation Partitioning Compared: Application to TiN/Ti/SiO2

A new method has been developed for the partitioning of sets of images with the objective of automatically identifying the number and locations of different regions in a material, The method is called automatic correlation partitioning and it involves the identification of clusters in the n-dimensional intensity histogram of a set of n images that are spatially registered, The method uses the peaks located in the simple intensity histograms of each image in the set to produce a list of all possible clusters in the entire data set, This list is then searched in order to find the actual clusters, The method is tested using data from a multi-imaging Auger electron microscope, which yields sets of Auger images characteristic of the spatial distributions of selected kinds of atoms in the surface of a solid, The first tests involve the use of a model sample consisting of a W overlay pattern on a Si substrate, The second tests are done on a TiN/Ti/SiO2 planar layer structure that has been ion beam bevelled to reveal a cross-section of the composition depth profile, The first set contains two images and the second set contains five images, The results of the new automatic method are compared with those obtained by the analyst working interactively with the data set to identify the clusters subjectively, Cluster analysis of the second sample reveals details of the interfacial layer chemistry not revealed by the interactive method and is consistent with published XPS depth profiling experiments reporting a titanium silicide layer at the Ti/SiO2 interface