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Articles 1 - 10 of 10
Full-Text Articles in Animal Sciences
Dopaminergic Input To The Equine Pituitary: Seasonal And Estradiol Effects, Sarah Case Clavier
Dopaminergic Input To The Equine Pituitary: Seasonal And Estradiol Effects, Sarah Case Clavier
LSU Master's Theses
Two experiments were conducted to study the effects of season and estradiol administration on dopaminergic input to the equine adenohypophysis. Experiment 1 began in the spring with 8 mares and 8 stallions and was repeated again in the summer, fall, and winter. Horses were given sulpiride injections of eight incremental doses (0.25 to 32 µg/kg BW). Within each group of 8 horses, half received the sulpiride in an increasing manner, the other half in a decreasing manner. Prolactin concentrations peaked in the first 15 to 30 min in all horses in all seasons. Prolactin areas under the curve increased (P < 0.001) with increasing doses of sulpiride, and were highest (P < 0.05) in March for stallions, but in June for mares. The calculated half-maximum values, which should be proportional to the dopaminergic input to the pituitary, were lowest (P < 0.05) in June and greatest in September. The variation in half-maximum values with season indicated a change in dopaminergic input to the pituitary, with lowest input occurring in June in both sexes. Experiment 2 was designed to determine if the degree of dopaminergic input to the adenohypophysis is altered by estradiol administration. Twelve geldings were used. On day 0, geldings received an i.m. injection of either estradiol cypionate (ECP; n = 6) or vegetable oil (n = 6) at one of two dose volumes (2 vs. 10 mL). On day 6, all geldings received an injection of sulpiride at 0.082 µg/kg BW in saline. Sulpiride injections were repeated every other day with the dose increasing each day, from 0.164 to 100 µg/kg BW. Estradiol pretreatment increased (P < 0.05) the prolactin response to sulpiride at the 2.56 µg/kg dose and higher. However, the half-maximum values for ECP-treated and control geldings did not differ, indicating that the amount of sulpiride needed to counterbalance the amount of dopamine reaching the pituitary was unaltered by estradiol treatment. It was concluded that estradiol likely stimulates prolactin production and secretion after sulpiride directly at the lactotrope level, rather than by decreasing hypothalamic dopamine input to the lactotropes.
Effects Of Meal Timing On Anabolic Hormone Status And Energy Metabolism In Neonatal Dairy Calves, Katherine Claire Simon
Effects Of Meal Timing On Anabolic Hormone Status And Energy Metabolism In Neonatal Dairy Calves, Katherine Claire Simon
LSU Master's Theses
Twelve neonatal Holstein bull calves (38.52 ± 5.87 kg) were fed milk replacer at a fixed or varied meal time to determine the effects on metabolic hormone secretion, average daily intake, growth, and energy metabolism. Body weights were measured every two weeks from birth to 8 weeks. Rumen fluid was collected every two weeks from week 2 through 8. Serial blood collections were conducted every two weeks from week 2 through 8. Blood was collected, beginning at 0530, at 0, 15, 30, 45, 60, 75, 90, 105, 120, 135, and 150 minutes. Plasma was analyzed for ghrelin, leptin, growth hormone …
Pregnancy Rates In Beef Cattle Artifically Inseminated With Frozen-Thawed Aged Beef Semen, David Barry Carwell
Pregnancy Rates In Beef Cattle Artifically Inseminated With Frozen-Thawed Aged Beef Semen, David Barry Carwell
LSU Master's Theses
The duration of frozen semen storage had no effect on pregnancy rates (60%, 61% and 61%, respectively) in Angus females inseminated with semen from 25 Angus bulls from Time Frames 1 (1960-1975), 2 (1976-1991) and 3 (1992-2006). Pregnancy rates were not different for beef females inseminated with semen from Time Frames 1, 2 and 3 (55%, 62% and 55%, respectively). There were no differences for total and progressive sperm motility across Time Frames 1 (42% and 29%), Time Frame 2 (51% and 38%) and Time Frame 3 (55% and 41%) and percentage of normal and abnormal sperm from bulls in …
Copper Oxide Wire Particles In Feed Pellets For Controlling Gastrointestinal Nematode Infection In Ewes And Lambs, Sarah Tammy Nicole Orlik
Copper Oxide Wire Particles In Feed Pellets For Controlling Gastrointestinal Nematode Infection In Ewes And Lambs, Sarah Tammy Nicole Orlik
LSU Master's Theses
Gastrointestinal nematode parasites cause extensive damage to small ruminants, and Haemonchus contortus is a major concern to production. In the past, small ruminants were dewormed at regular intervals and control methods were based primarily on the use of anthelmintics. At present, anthelmintic resistance has been reported worldwide and has developed into a serious problem for small ruminant management programs. In view of this, alternate control methods are needed. One alternative method is the use of copper oxide wire particles (COWP). Three independent trials were conducted during Spring, Summer, and Fall of 2008. Two trials evaluated the effect of COWP in …
Cell Extract-Based Reprogramming Of Somatic Cells, Laura Whitney Coley
Cell Extract-Based Reprogramming Of Somatic Cells, Laura Whitney Coley
LSU Master's Theses
The differentiation potential of adult stem cells (ASC) has long been thought to be limited to cell lineages present in the organ from which they are derived; however, several studies have challenged this notion by demonstrating that some ASC exhibit a remarkably high degree of plasticity. Unlike terminally differentiated somatic cells, the less differentiated state of ASC can assume the functional phenotypes and expression profiles of cells unique to other tissues. The expansive repertoire of differentiation potential exhibited by ASC suggests these cells possess characteristics similar to pluripotent cells, including epigenomic regulatory pattern. Therefore, ASC may be better equipped for …
Effects Of Varying Levels Of Cottonseed Hulls On Growth And Metabolic Indications Of Rumen Development Of Dairy Calves, Ryan Doescher
Effects Of Varying Levels Of Cottonseed Hulls On Growth And Metabolic Indications Of Rumen Development Of Dairy Calves, Ryan Doescher
LSU Master's Theses
A study was conducted to determine the effects of varying levels of cottonseed hulls on growth and metabolic indications of rumen development of dairy calves. Sixty-four Holstein calves (Heifers, n=40; Bulls, n=24) were randomly assigned to one of four dietary treatments which included calf starters containing no cottonseed hulls (control; C), 10% cottonseed hulls (10% CSH), 15% cottonseed hulls (15% CSH), or 20% cottonseed hulls (20% CSH). Calves were fed their respective treatments beginning on day 6 until day 56 of age. Body weights were measured at birth and biweekly thereafter until day 56 of age. Wither and hip heights …
Influence Of Low Homogenization Pressures On Acid Tolerance, Bile Tolerance, Protease Activity, And Growth Characteristics Of Lactobacillus Delbrueckii Ssp Bulgaricus Lb-12, Streptococcus Salivarius Ssp Thermophilus St-M5, And Lactobacillus Acidophilus La-K, Tanuja Muramalla
LSU Master's Theses
Lactobacillus delbrueckii ssp bulgaricus LB-12, Streptococcus salivarius ssp thermophilus ST-M5 and Lactobacillus acidophilus LA-K are dairy cultures widely used in the fermentation of dairy products. Homogenization is an essential process in dairy industry for making several products. High homogenization pressures (>50 MPa) are used to create stable emulsion, inactivate the pathogens and increase the protease activity of dairy cultures. Sparse literature is available on the influence of low homogenization pressures, and their effect on beneficial characteristics of dairy cultures is not well understood. The objective of this study was to determine the effect of low homogenization pressures on acid …
Prepartum Maternal Cortisol Concentrations On Postnatal Cortisol Concentration And Immunoglobulin Absorption In Neonatal Dairy Calves, Dana Nadine Wooley
Prepartum Maternal Cortisol Concentrations On Postnatal Cortisol Concentration And Immunoglobulin Absorption In Neonatal Dairy Calves, Dana Nadine Wooley
LSU Master's Theses
The role of glucocorticoids on intestinal closure in neonates has recently become an area of interest but a definitive mechanism remains to be identified. It is known that glucocorticoids enhance immunoglobulin absorption in dairy calves, but the role of maternal glucocorticoids at parturition is not clear. In the present experiment, we obtained plasma and milk samples from primiparous and multiparous Holstein cows (n=24) to measure cortisol at 72, 48 and 24 hours before and 3, 6, 12, 24 and 48 hours after spontaneous parturition. After parturition, calves (n=24) were immediately removed from their dams and a blood sample was taken …
Laser-Assisted Zona Pellucida Hatching Of Frozen-Thawed In Vivo-Produced Bovine Embryos, Mindy Kaye Chiasson
Laser-Assisted Zona Pellucida Hatching Of Frozen-Thawed In Vivo-Produced Bovine Embryos, Mindy Kaye Chiasson
LSU Master's Theses
Incomplete zona hatching or failure of the zona to rupture compromises post-transfer embryo viability and conceptus development. Assisted hatching prior to the transfer of frozen-thawed bovine embryos has been proposed as a means to increase recipient pregnancy rates. The objective of this study was to determine if laser-assisted hatching would improve in vivo-produced frozen-thawed bovine embryo hatching and pregnancy rates. In Experiment I,II and III frozen direct-transfer embryos received either two a or three symmetrical rents at either 40% or 80% through the outer zona surface using the Hamilton Thorne XYClone® (Hamilton Thorne Biosciences) diode laser at 90% power with …
Effects Of Serum Addition To Culture Medium On Gene Expression In Day-7 And Day-14 Bovine Embryos, Jaime Manuel Angulo Campos
Effects Of Serum Addition To Culture Medium On Gene Expression In Day-7 And Day-14 Bovine Embryos, Jaime Manuel Angulo Campos
LSU Master's Theses
The addition of serum to embryo culture media may alter gene expression and trigger development of Large Offspring Syndrome. The objectives of this study were to determine gene expression levels in embryos cultured in the absence or presence of 5% calf serum and compare these expression patterns to in vivo derived embryos (IVD), and to determine the effects of serum on the length of day-14 embryos. Abattoir derived oocytes were fertilized and cultured in mSOFaa. At 72 hours post-insemination (hpi), embryos were randomly allocated into two treatments: mSOFaa without and with 5% calf serum. Embryos were then cultured to 168 …