Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Louisiana State University

Discipline
Keyword
Publication Year
Publication
Publication Type

Articles 3451 - 3480 of 4162

Full-Text Articles in Entire DC Network

Isolation And Characterization Of Macrophage Inhibitory Compounds From Mycobacterium Paratuberculosis., Murray Elison Hines Ii Jan 1991

Isolation And Characterization Of Macrophage Inhibitory Compounds From Mycobacterium Paratuberculosis., Murray Elison Hines Ii

LSU Historical Dissertations and Theses

Fractions exhibiting activity detrimental to the killing function of activated bovine monocyte/macrophages towards Candida albicans were obtained from Mycobacterium paratuberculosis. Active fractions were initially derived by ultrasonication of bacterial samples followed by ammonium sulfate precipitation, ion-exchange chromatography, gel filtration chromatography, heat precipitation, acid precipitation and alkali treatment. Two different fractions that exhibited marked inhibition of macrophage killing ability were derived and partially characterized. Novel methodology was developed to accomplish the task of lysis and fractionation of mycobacteria utilizing the Matrix Solid Phase Dispersion (MSPD) technique that appeared to be much more efficient and is certainly less time consuming and less …

Go to article

Environmental Factors And Production Characteristics Affecting The Culture Of Red Drum, Sciaenops Ocellatus., Rowland Glenn Thomas Jan 1991

Environmental Factors And Production Characteristics Affecting The Culture Of Red Drum, Sciaenops Ocellatus., Rowland Glenn Thomas

LSU Historical Dissertations and Theses

Experiments with red drum, Sciaenops ocellatus, were conducted to assess environmental requirements and culture characteristics. Pond trials were used to evaluate the effects of salinity, chloride source, predator control, acclimation procedure, stocking density, and size at stocking on production. Survival in individual ponds ranged from 0-92%; average daily weight gain from 0.46-2.22g; and feed conversion ratio from 2.30-4.90. Survival, growth, and feed conversion ratio did not differ significantly between equivalent treatments in saltwater and freshwater ponds. The minimum chloride concentration necessary for acceptable production of red drum in freshwater ponds (250-300 mg/l) was at least 100% higher than the concentrations …

Go to article

Nuclear Transplantation: Intracellular Release And Extracellular Influx Of Calcium In Response To Electrofusion Pulse And Its Effect On Murine Oocyte Activation And Embryonic Development., Lee F. Rickords Jan 1991

Nuclear Transplantation: Intracellular Release And Extracellular Influx Of Calcium In Response To Electrofusion Pulse And Its Effect On Murine Oocyte Activation And Embryonic Development., Lee F. Rickords

LSU Historical Dissertations and Theses

The transplantation of early embryonic cell nuclei into oocytes in which the maternal chromosomes have been removed is a method by which multiple offspring of the same genotype can be produced. One critical factor required for successful development of nuclear transfer derived embryos is inducing the release of the recipient ooplasm from meiotic arrest (activation). This is accomplished during fusion of the two cells. The DC electrofusion pulse used to fuse the two cells together also activates the recipient ooplasm to resume meiotic events, however, the efficiency of electrofusion pulse induced activation remains low. It is known that activation of …

Go to article

Study On Two Chitin-Binding Proteins From Vibrio Parahaemolyticus., Otto Silva Gildemeister Jan 1991

Study On Two Chitin-Binding Proteins From Vibrio Parahaemolyticus., Otto Silva Gildemeister

LSU Historical Dissertations and Theses

Two chitin-binding proteins from Vibrio parahaemolyticus are secreted into the culture medium after the addition of chitin or oligomers of N-acetylglucosamine, but only to lower levels of expression with a few other saccharides. The first protein exhibited a very salt-resistant chitinase activity with activity maxima at pH 6 and 9. The enzyme is stable for 30 minutes at 40$\sp\circ$C, and maximal activity is reached at 50$\sp\circ$C. The chitinase hydrolyzes optimally chitin oligomer substrates with degree of polymerization of 4 and higher. The hydrolytic activity upon the chitotrimer is low; the dimer cannot be hydrolyzed by the enzyme. When incubated with …

Go to article

Louisiana Principals' Perceptions Of Nontraditional Vocational Teachers And The Importance Of Vocational Education., Moo Yul Huh Jan 1991

Louisiana Principals' Perceptions Of Nontraditional Vocational Teachers And The Importance Of Vocational Education., Moo Yul Huh

LSU Historical Dissertations and Theses

Even though the elimination of sex bias and stereotyping has been a national priority in vocational education for a number of years, many educators or administrators still hold sex biased and stereotyped attitudes about labor force participation and have a belief that there are "men's" and "women's" jobs. A study of sources affecting sex bias and sex stereotyping of vocational teachers is critical to provide more productive programs. The local school principal typically has the greatest impact on school level employment decisions because the principal is the chief executive officer or administrator of the basic unit in the school system. …

Go to article

Characterization And Potential Utilization Of Proteases From The Hepatopancreas Of Crawfish, Procambarus Clarkii., Hyeung-Rak Kim Jan 1991

Characterization And Potential Utilization Of Proteases From The Hepatopancreas Of Crawfish, Procambarus Clarkii., Hyeung-Rak Kim

LSU Historical Dissertations and Theses

Four electrophoretically homogenous anionic trypsins, tentatively named trypsin A, B, C, and D, were isolated from crawfish hepatopancreas. Purity was increased 56, 100, 87, and 64-fold with approximately 2.4, 8.1, 5.1, and 3.0% yield for trypsin A, B, C, and D, respectively. The molecular weights of trypsin A, B, C, and D were estimated to be 23,800, 27,900, 24,800, and 31,400, respectively, using Sephacryl S-200 gel filtration. Isoelectric points and amino acid profiles of the trypsins were similar. Caseinolytic activity was consistently highest between pH 5.5 and 10.0 for all trypsins. Amidolytic and esterolytic activities were maximum in a narrower …

Go to article

Effects Of Alternative Protein And Fat Payment Plans On Production Variables And Returns In Louisiana Dairy Herds., Leonder Labbe Jan 1991

Effects Of Alternative Protein And Fat Payment Plans On Production Variables And Returns In Louisiana Dairy Herds., Leonder Labbe

LSU Historical Dissertations and Theses

Multiple linear regression was used to compare the impact of proposed multiple component milk pricing systems with the present milk pricing system for Louisiana Holstein herds on DHIA. Dependent variables were milk yield, fat yield, protein yield, six income over feed cost pricing systems, and six product value pricing systems. Independent variables were herd, year, and month as class variables and 18 production variables. Data were 16,675 herd-year-month observations of Louisiana Holsteins from DHIA monthly Herd Summary DHI-202 computer files. Pricing data was standardized using prices form the New Orleans - Mississippi Federal Milk Marketing Order 1094, Zone 1. The …

Go to article

Chromium, Tryptophan, And Picolinate In Diets For Pigs And Poultry., Timothy Guinn Page Jan 1991

Chromium, Tryptophan, And Picolinate In Diets For Pigs And Poultry., Timothy Guinn Page

LSU Historical Dissertations and Theses

Six experiments were conducted to evaluate the effects of supplemental dietary tryptophan (TRP), picolinate (Pic), CrCl$\sb3\cdot$6H$\sb2$O, chromium picolinate (CrPic), or a combination of Pic and CrCl$\sb3\cdot$6H$\sb2$O on growth performance, liver mineral concentrations, insulin, growth hormone, organ weights, and serum and carcass traits of pigs. One experiment was conducted to evaluate the effect of chromium picolinate (CrPic) on serum cholesterol (CH), egg CH, egg quality, and egg production of laying hens. Dietary TRP, Pic, CrCl$\sb3\cdot$6H$\sb2$O, and a combination of Pic and CrCl$\sb3\cdot$6H$\sb2$O did not affect growth performance, liver mineral concentrations, insulin, growth hormone, and serum and carcass traits of pigs. The …

Go to article

Curriculum Reform From Multicultural Perspectives: The Analysis Of An Urban School District's Systemic Process. (Volumes I And Ii)., Linda Johnson Stelly Jan 1991

Curriculum Reform From Multicultural Perspectives: The Analysis Of An Urban School District's Systemic Process. (Volumes I And Ii)., Linda Johnson Stelly

LSU Historical Dissertations and Theses

Crises in the economic and social conditions of the underrepresented have led to the analysis of education and the schooling process for responses to and explanations for these inequalities. The purpose of this ethnographically informed, autobiographic case study is to examine the relational and contradictory dynamics of an urban southern school district's systemic process of educational reform from multicultural perspectives. The case study examines the rules, roles and relationships of key change agents and stakeholders as they define education from multicultural perspectives in the process of change. The research further examines the developmental processes necessary to transform the existing curriculum …

Go to article

Structure Of Synthetic Oligosaccharides By Tandem Mass Spectrometry., Eunsun Yoo Yoon Jan 1991

Structure Of Synthetic Oligosaccharides By Tandem Mass Spectrometry., Eunsun Yoo Yoon

LSU Historical Dissertations and Theses

Certain linkage positions in oligosaccharides can be discerned by collision-activated dissociation mass spectrometry (MS-CID-MS), rationalized by molecular modeling. The first part of this dissertation shows that linkage-specific daughter ion spectra of synthetic amino-sugar containing oligosaccharides can be obtained from several alkylated derivatives such as sodiated, potassiated, ammoniated and lithiated derivatives. Methylated derivatives of the synthetic oligosaccharides give more useful linkage discernment product-ions, including a 3-linkage specific ion. A novel approach of relating daughter ion to parent ion ratios and collision energy is described and is predictive of linkage position in the first set of six oligosaccharides used. In the second …

Go to article

Timed Daily Thermopulses Alter The Circadian Hormonal Regulation Of Glucose And Lipid Metabolism., Christopher Joseph De Souza Jan 1991

Timed Daily Thermopulses Alter The Circadian Hormonal Regulation Of Glucose And Lipid Metabolism., Christopher Joseph De Souza

LSU Historical Dissertations and Theses

Studies were made in Syrian hamsters and Holtzman rats to examine roles for circadian rhythms in the control of body fats stores. Baseline and circadian rhythms of plasma insulin varied seasonally in the Syrian hamster. Baseline concentrations of the hormone were almost 4 times greater in scotosensitive female hamsters held on short daily photoperiods when they were fat than in lean animals at other seasons and other photoperiodic schedules. Additionally, plasma insulin levels in fat hamsters, but not in lean animals, peaked at light onset when lipogenic responsiveness to insulin is greatest. The circadian rhythms of plasma insulin are not …

Go to article

Ruminal Distribution And Utilization Of Zinc And Magnesium As Influenced By Dietary Source And Energy Level., Donald Wayne Kennedy Jan 1991

Ruminal Distribution And Utilization Of Zinc And Magnesium As Influenced By Dietary Source And Energy Level., Donald Wayne Kennedy

LSU Historical Dissertations and Theses

Steers fed a conventional diet were utilized to determine the effects of various Zn supplements on ruminal distribution of Zn. Treatments consisted of a basal (B) diet (no Zn supplementation) and B supplemented with equal parts of Zn from either a polysaccharide complex of Zn (PC-Zn) or zinc oxide (ZnO). Samples were fractionated into four fractions: a cell-free fraction, a particulate fraction and two microbial fractions. After PC-Zn or ZnO were dosed intraruminally, relative distribution of Zn from each Zn source within each fraction was evaluated up to 8 h postdosing. Cannulated growing lambs were used to study the effects …

Go to article

Conceptus-Derived Immunosuppressive Factors And Their Role In Fetal Allograft Protection., Terri Lynn Roth Jan 1991

Conceptus-Derived Immunosuppressive Factors And Their Role In Fetal Allograft Protection., Terri Lynn Roth

LSU Historical Dissertations and Theses

The role of conceptus-derived immunosuppressive factors in protecting the fetal allograft was investigated by first examining the immunosuppressive activity derived from ovine, caprine and hybrid conceptus trophoblast tissue. Medium conditioned by 20 day-old conceptus trophoblast tissue from each species suppressed sheep and goat lymphocyte proliferation (P $$.05) between the immunosuppressive effects of the three media on either sheep or goat lymphocytes. In subsequent studies, horse conceptus-conditioned medium (HCCM) derived from embryos at days 9, 15 and 26 of gestation, suppressed mitogen-stimulated horse lymphocytes (P $<$.001). HCCM maintained its suppressive activity following heating and repeated freeze-thawing. Using microconcentrator centrifugation, it was determined that the suppressor factor(s) was $>$100,000 MW. HCCM was tested in donkey and goat lymphocyte cultures and proved capable of …

Go to article

Louisiana Agriculture Magazine, Summer 1990, Lsu Agricultural Experiment Station Jul 1990

Louisiana Agriculture Magazine, Summer 1990, Lsu Agricultural Experiment Station

Louisiana Agriculture

No abstract provided.

Go to article

Cenobium 1990, Louisiana State University And Agricultural And Mechanical College, School Of Veterinary Medicine, Terry Doyle Jan 1990

Cenobium 1990, Louisiana State University And Agricultural And Mechanical College, School Of Veterinary Medicine, Terry Doyle

Cenobium Yearbook

Cenobium began publication in 1977 and continued through 1990. Produced by students, the yearbooks are a chronicle of the daily life and the special events experienced by veterinary students at the LSU School of Veterinary Medicine.

Go to article

Louisiana Agriculture Magazine, Winter 1990-1991, Lsu Agricultural Experiment Station Jan 1990

Louisiana Agriculture Magazine, Winter 1990-1991, Lsu Agricultural Experiment Station

Louisiana Agriculture

No abstract provided.

Go to article

Age Of Onset And Duration Variables: Relationship To Primary And Secondary Psychopathology Of Bulimia Nervosa., Darlene Broussard Witcher Jan 1990

Age Of Onset And Duration Variables: Relationship To Primary And Secondary Psychopathology Of Bulimia Nervosa., Darlene Broussard Witcher

LSU Historical Dissertations and Theses

Over the past decade there has been growing concern about the syndrome of bulimia nervosa. Current theoretical models of the etiology and symptomatology of bulimia predict that the psychopathology of the eating disorder worsens over time. The specific purposes of this study was to examine the effect of onset age and duration of the disorder on the primary and secondary psychopathology of bulimia nervosa at the time of presentation for treatment. The results suggest that binging and purging worsen with increasing duration and older age of onset, accompanied by increased weight and greater distortion of body size estimation. Furthermore, subjects …

Go to article

Assessment Of Athletic Potential And Augmentation Of Performance In Thoroughbred Racehorses., John Daniel Harkins Jan 1990

Assessment Of Athletic Potential And Augmentation Of Performance In Thoroughbred Racehorses., John Daniel Harkins

LSU Historical Dissertations and Theses

The purposes of this dissertation were to (1) determine running abilities of horses on the racetrack, (2) design treadmill standard exercise tests (SETs) to measure exercise variables that correlate with racetrack performance, and (3) assess the influence of training, competition, and ergogenic aids on performance. Run times of 25 Thoroughbreds were determined during solo and competitive track runs of 1200, 1600, and 2000 meters. Cardiac, respiratory, and hematologic variables were later measured during treadmill SETs. Variables were correlated with average run times. Heart rate scores, V$\sb{200}$, plasma lactate values, and maximal oxygen uptake correlated best with performance. Interval and conventional …

Go to article

Effects Of Gel Teat Cleaning And Sanitizing On Raw Milk Quality And Udder Health., Kasimu Hudu Ingawa Jan 1990

Effects Of Gel Teat Cleaning And Sanitizing On Raw Milk Quality And Udder Health., Kasimu Hudu Ingawa

LSU Historical Dissertations and Theses

Thirty lactating Holstein cows were divided into three groups of ten each and assigned to three treatments. The first treatment required using a gel teat sanitizer cleaner (GEL) and paper towels, no water to clean teats prior to milking. The second used only water (WASH) and paper towels, and the third used water, paper towels, and predipping (PREDIP) with 0.5% iodophor solution. Individual cow samples of milk were aseptically collected weekly from weigh jars for ten weeks. Bacteria counts were determined. Microorganism counts were also monitored from individual cow teat swabs. Treatment effects on daily milk yield, fat and protein …

Go to article

Effects Of Artificial Mineral Licks On White-Tailed Deer., Stephen Redmore Schultz Jan 1990

Effects Of Artificial Mineral Licks On White-Tailed Deer., Stephen Redmore Schultz

LSU Historical Dissertations and Theses

A commercial mineral mixture for deer was used to evaluate the effects of broad-spectrum dietary mineral supplementation on white-tailed deer (Odocoileus virginianus) growth, antler development, and tissue mineral content. Forty-two artificial mineral licks for deer were established on 3 study areas in East Feliciana Parish, Louisiana. All licks were monitored monthly, recharged to original level if used, and mineral consumption recorded from May 1988 through December 1989. Consumption data were converted to estimated average per deer values based on population estimates. Effects of artificial lick mineral consumption on free-ranging deer were examined by comparing deer harvested during the 1988-89 and …

Go to article

Effects Of Food Plots On Selected Growth Parameters, Productivity, And Harvesting Of White-Tailed Deer In A National Forest., Kenneth Dale Dancak Jan 1990

Effects Of Food Plots On Selected Growth Parameters, Productivity, And Harvesting Of White-Tailed Deer In A National Forest., Kenneth Dale Dancak

LSU Historical Dissertations and Theses

A total of 8.1 ha of warm-season and 16.8 ha of cool-season food plots were installed on 2 of 4 study units at National Red Dirt Wildlife Management Preserve, Louisiana, an area managed by the USDA Forest Service for multiple resources. Mean ($\pm$ s.e.) study unit size was 2220 $\pm$ 246 ha. No food plots were installed on the remaining 2 study units (controls). Warm-season food plots were planted with American jointvetch (Aeschynomene americana); cool-season plots were planted with red clover (Trifolium pratense), subterranean clover (Trifolium subterraneum), winter wheat (Triticum aestivum) and white clover (Trifolium repens). All plots were maintained …

Go to article

Impact Evaluation Of The Louisiana Cooperative Extension Service Clothing Education Program., Evva L. Zeagler Wilson Jan 1990

Impact Evaluation Of The Louisiana Cooperative Extension Service Clothing Education Program., Evva L. Zeagler Wilson

LSU Historical Dissertations and Theses

The objectives of this study were to determine: the practices of the LCES clothing program audience and of the general public, if differences exist between factors of the clothing program audience and the general public when controlled for urban or rural status, and if respondent characteristics are significant predictors of clothing practice factors. The research procedure utilized a descriptive design. A questionnaire was mailed to 400 randomly-selected Louisiana homemakers for each of four strata of Extension audience (urban and rural) and general public (urban and rural). Descriptive statistics were used to define the samples. Factor analysis was computed on 41 …

Go to article

A Comparative Study Of The Effects Of Sesbania Drummondii On The Hepatic Cytochrome P-450 Monooxygenase Systems Of Chickens And Rats., Marcy Iva Banton Jan 1990

A Comparative Study Of The Effects Of Sesbania Drummondii On The Hepatic Cytochrome P-450 Monooxygenase Systems Of Chickens And Rats., Marcy Iva Banton

LSU Historical Dissertations and Theses

The effect of an extract of Sesbania drummondii on the hepatic cytochrome P-450 monooxygenase system was evaluated in two experimental models, the White Leghorn chicken and the Sprague-Dawley rat. The cytochrome P-450 monooxygenase systems were compared using studies of catalytic activities and two major enzyme components, cytochrome P-450 and NADPH-cytochrome P-450 reductase. Two "classical" cytochrome P-450 inducers, phenobarbital and $\beta$-naphthoflavone, were used to probe induction mechanisms. S. drummondii induced opposite effects on the hepatic cytochrome P-450 component of chickens versus rats. Cytochrome P-450 specific content was increased 2-fold in chickens but decreased 2-fold in rats. Qualitative differences in microsomal proteins …

Go to article

Isolation And Physical Mapping Of The Mitochondrial Chromosome From The Zygomycete Mucor Racemosus., Mary Louise Schramke Jan 1990

Isolation And Physical Mapping Of The Mitochondrial Chromosome From The Zygomycete Mucor Racemosus., Mary Louise Schramke

LSU Historical Dissertations and Theses

Mitochondria were isolated from Mucor racemosus and DNA was purified from these organelles by cesium chloride/ethidium bromide isopycnic centrifugation. Examination of mitochondrial DNA samples with a transmission electron microscope revealed a circular mitochondrial chromosome approximately 63.8 kbp in length. Summation of restriction fragments of mitochondrial DNA separated by agarose gel electrophoresis yielded a comparable value of 63.4 kbp for the size of the intact molecule. Electrophoretic mobility and stoichiometry were determined for restriction fragments generated using nine different restriction enzymes. A physical map was deduced from single and double digestions of mitochondrial DNA with several of the restriction enzymes. The …

Go to article

The Eating Disorders Diagnostic Inventory (Eddi): The Development Of A New Assessment Instrument., Cecilia Jo Davis Jan 1990

The Eating Disorders Diagnostic Inventory (Eddi): The Development Of A New Assessment Instrument., Cecilia Jo Davis

LSU Historical Dissertations and Theses

The area of eating disorders have been intensively by both the psychological and medical researchers over the last two decades. Differential diagnosis of the four most prevalent eating disorders (anorexia nervosa, bulimia nervosa, compulsive overeating, and the non-binging obese) continues to be a problem for both researchers and clinicians. Diagnosis of these disorders has been complicated by the many changes in diagnostic criteria for each of the disorders. One consequence of these frequent changes is that there is no single self-report inventory for differential diagnosis which is based on currently accepted diagnostic criteria. The purpose of this study was the …

Go to article

Sampling And Analysis Of Dynamic Headspace Volatile Compounds From Selected Protein-Rich Food Matrices., Jose Ernesto Matiella Jan 1990

Sampling And Analysis Of Dynamic Headspace Volatile Compounds From Selected Protein-Rich Food Matrices., Jose Ernesto Matiella

LSU Historical Dissertations and Theses

Volatile compounds from two protein-rich foods, crabmeat and eggs, were studied with emphasis on qualitative and quantitative determination of a wide variety of chemical substances including degradation compounds from amino acids, lipids and carboyhdrates as well as compounds derived from the packaging material and the environment. Boiled and pasteurized blue crab (Callinectes sapidus) meat samples were analyzed for volatile flavor components by dynamic headspace sampling, capillary column gas chromatography and mass spectrometry. Fifty-three volatile compounds were identified in crabmeat samples. Levels of volatile compounds in both samples were compared and it was found that the boiled crabmeat contained higher levels …

Go to article

Predicting Potassium Uptake By White Clover With A Mathematical Model And Assessment Of White Clover Phosphorus And Potassium Status With The Dris., Hubert Joseph Savoy Jr Jan 1990

Predicting Potassium Uptake By White Clover With A Mathematical Model And Assessment Of White Clover Phosphorus And Potassium Status With The Dris., Hubert Joseph Savoy Jr

LSU Historical Dissertations and Theses

Environmental concerns emphasize the requirement for diagnostic tools compatible with more intensively managed agricultural systems. Two recent approaches, the Barber-Cushman mechanistic model and the Diagnosis and Recommendation Integrated System (DRIS), appear to offer more accurate predictions of soil nutrient supply and more flexible means of assessing plant nutrient status, respectively, than conventional methods. The objectives of this research were to verify the aforementioned models for predicting K uptake and assessing P and K status of LA S-1 white clover. In growth chamber experiments, the Barber-Cushman model correctly predicted K uptake by plants for up to 21 days from Rita muck, …

Go to article

Regulation Of Cortisol And Prolactin In Horses., Donald R. Colborn Jan 1990

Regulation Of Cortisol And Prolactin In Horses., Donald R. Colborn

LSU Historical Dissertations and Theses

In Experiment I, stallion exposure to an estrous mare on d 2 caused cortisol and PRL concentrations to increase (P $$.05) on d 1, 3, 4, 5 or 6 when no exposure occurred. In Experiment II, cortisol concentrations increased (P $<$.05) within 10 min after sexual stimulation (SS), physical exercise (PE), restraint via a twitch (RT) and epinephrine administration (EA) but not during control bleedings. PRL concentrations increased (P $<$.05) following SS, PE and RT but not after EA or during control bleedings. In Experiment III, cortisol concentrations in geldings increased (P $<$.05) following EA, PE and RT but not following SS or control bleedings. PRL concentrations increased (P $<$.05) following PE and SS. In Experiment IV, sulpiride injection was used in stallions in an attempt to increase PRL concentrations. Prior to sulpiride treatment, concentrations of both cortisol and PRL increased (P $<$.05) by 40 to 80% in response to exercise; concentrations of LH and FSH also increased (P $<$.05) by approximately 10%. Sulpiride treatment stimulated (P $<$.05) daily PRL secretion by approximately 5-fold, and caused a decrease (P $<$.05) in daily FSH secretion whereas only isolated differences (P $<$.05) occurred between treatment groups for daily LH and cortisol secretion. At the end of treatment, there was no PRL response to exercise for stallions treated with sulpiride, but there was (P $<$.05) for control stallions; only control stallions exhibited a marginal cortisol response (P $<$.05) to exercise. The PRL response to TRH was increased (P $<$.05) 4-fold in stallions treated with sulpiride but was unchanged in control stallions. Sulpiride treatment did not affect (P $>$.05) the LH or FSH response to exogenous GnRH. We conclude that: (1) returning stallions to the site of a previous period of sexual excitement does not cause a memory-mediated rise in cortisol or prolactin; (2) cortisol and PRL are secreted rapidly in response to some but not all forms of physical and chemical stress in stallions and geldings; …

Go to article

Factors Affecting Conceptus Loss In Cattle., Daniel Patrick Ryan Jan 1990

Factors Affecting Conceptus Loss In Cattle., Daniel Patrick Ryan

LSU Historical Dissertations and Theses

In the first experiment, the temperature humidity index (THI) was compared with pregnancy rates (PR) in bovine females under two different environmental cooling systems. The PR decreased if the THI was greater on the second day prior to or after mating compared with that of the day of mating. In the second experiment, the stages of embryo mortality in the first 40 days of gestation were identified in the hot and cool seasons of the year. At day 13 or 14 of pregnancy 27% of embryos were viable in the hot months, which was less than 60% at day 13 …

Go to article

The Socioeconomic Aspects Of Beef Cattle Production In Louisiana., Emmanuel Kagaba Nzabanita Jan 1990

The Socioeconomic Aspects Of Beef Cattle Production In Louisiana., Emmanuel Kagaba Nzabanita

LSU Historical Dissertations and Theses

This study was divided into: (1) a descriptive study of the farm resources, management practices, veterinary services utilization, and socio-psychological characteristics of Louisiana ranchers in relation to beef cattle performance, (b) a classification of the ranchers according to their utilization of veterinary services with the objective of identifying producer characteristics that are associated with frequent, moderate, and non-use of veterinary services, and (c) identification of factors associated with continuing or ending beef cattle production. The intensity of management, herd health and veterinary services utilization was quantified by scoring and ranking indicator variables that defined these composite variables. Most ranchers had …

Go to article

First Prev Next Last