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Full-Text Articles in Animal Sciences

Highway Effects On Small Mammal Communities And Effectiveness Of A Deer-Vehicle Collision Mitigation Strategy, Silvia A. S. Rosa May 2006

Highway Effects On Small Mammal Communities And Effectiveness Of A Deer-Vehicle Collision Mitigation Strategy, Silvia A. S. Rosa

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

My work focused on the study of road effects and mitigation of negative impacts of roads on wildlife. Two different studies were conducted on Interstate 15, in southern Utah. My first study reported on road effects on small mammal communities. The results suggested that overall, there was no clear effect on small mammal populations relative to distance from the road. Most small mammal species did not appear to be negatively affected by the presence of the road. Instead, the road seemed to have either a neutral or a positive effect. The abundance and diversity of small mammals responded more markedly …


Remapping The Cliff Chipmunk (Neotamias Dorsalis) Distribution And Creating A Habitat Association Model In Southern Idaho, Masako Niwa May 2006

Remapping The Cliff Chipmunk (Neotamias Dorsalis) Distribution And Creating A Habitat Association Model In Southern Idaho, Masako Niwa

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The distribution of the cliff chipmunk in Idaho was previously considered to include only the Raft River Valley and the Goose Creek Basin. A pilot study was conducted in 2003 and 2004. Thirty-five cliff chipmunk presence locations and 124 absence locations were recorded. Habitat variables of elevation, slope, deviation from south, distance to water, and vegetation type were extracted for all of the absence and presence points by means of GIS analysis. The data were analyzed by implementing a classification tree, and a "GIS habitat association model" was created. The model was tested in 2005, and the overall model accuracy …


Catalase Activity Mediates The Inhibitory Actions Of 24,25 Dihydroxyvitamin D3, Sven L. Peery May 2006

Catalase Activity Mediates The Inhibitory Actions Of 24,25 Dihydroxyvitamin D3, Sven L. Peery

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The steroid hormone 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] rapidly stimulates the uptake of phosphate in isolated chick intestinal cells, while the steroid 24,25-dihydroxyvitamin D3 [24,25(OH)2D3] inhibits the rapid stimulation by 1,25(OH)2D3. Earlier work in this laboratory has indicated that a cellular binding protein for the 24,25(OH)2D3 is the enzyme catalase. Since binding resulted in decreased catalase activity and increased H2O2 production, studies were undertaken to determine if pro-oxidant conditions mimicked the inhibitory actions of 24,25(OH)2D3, and anti-oxidant conditions …


Tapirs And Rhinoceroses In Captivity: An Examination Of The North American Captive Populations And Their Husbandry, Lisa A. Nordstrom May 2006

Tapirs And Rhinoceroses In Captivity: An Examination Of The North American Captive Populations And Their Husbandry, Lisa A. Nordstrom

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

All species of Tapiridae and Rhinocerotidae are threatened or endangered in the wild. Captive populations have been established for most of these species, but successful management has proved challenging. Effective ex situ conservation strategies, however, rely on the ability of zoological institutions to maintain and breed these endangered species. In this study, I examined the captive environment to identify the factors associated with reproduction, mortality, and health of rhinos and tapirs. Zoological institutions in the North American region that currently housed rhinos and/or tapirs were surveyed in 2003. Attaining an approximately 90% response rate, I compiled information on the following …


Bird And Small Mammal Communities Of Sagebrush-Dominated Mountain Meadows: An Examination Of Meadow Characteristics As Part Of A Hierarchical, Multi-Level Study Of The Wasatch-Cache National Forest, Elizabeth Johnson May 2005

Bird And Small Mammal Communities Of Sagebrush-Dominated Mountain Meadows: An Examination Of Meadow Characteristics As Part Of A Hierarchical, Multi-Level Study Of The Wasatch-Cache National Forest, Elizabeth Johnson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Sagebrush shrubsteppe ecosystems have increasingly garnered attention as an endangered ecosystem. Ninety nine percent of all sagebrush ecosystems are thought to have been impacted by humans, and over 50% of grassland and shrubsteppe species are believed to be in decline. Most of the research on sagebrush ecosystems has been conducted at lower elevations and in large expanses of sagebrush. A considerable amount of sagebrush is found at higher elevations, often in meadows found within a forest matrix. The role of this high-elevation habitat is poorly understood. We conducted bird, small mammal, vegetation, and soil surveys in sagebrush-dominated mountain meadows within …


Wildlife-Vehicle Collisions In Utah: An Analysis Of Wildlife Road Mortality Hotspots, Economic Impacts And Implications For Mitigation And Management, Christine A. Kassar May 2005

Wildlife-Vehicle Collisions In Utah: An Analysis Of Wildlife Road Mortality Hotspots, Economic Impacts And Implications For Mitigation And Management, Christine A. Kassar

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In the US, the roaded landscape has had serious ecological effects. We studied wildlife-vehicle collisions occurring on the 248 state routes in Utah from 1992 to 2002. We tracked trends and patterns in deer-vehicle collisions, evaluated all routes for frequency of deer kills, and identified "hotspots" (segments of road with high concentrations of collisions per mile). We found pronounced patterns: e.g., 61.15% of all collisions occurred on only 10 routes. We studied the effects of posted speed limit and annual average daily traffic flow and found that no relationship existed between traffic volume and/or posted speed limit and the number …


Feeding Behavior Of Sheep In Relation To Kinetics Of Sagebrush Monoterpenes: Implications For Landscape Biodiversity, Luthando E. Dziba May 2004

Feeding Behavior Of Sheep In Relation To Kinetics Of Sagebrush Monoterpenes: Implications For Landscape Biodiversity, Luthando E. Dziba

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The sagebrush steppe is one of the most extensive vegetation types in the western US and an important habitat for wild and domestic herbivores. When sagebrush dominates, however, forage and habitat quality decline. Although sagebrush is nutritious, its forage value is reduced by terpenes. A better understanding of how terpenes limit intake is vital for increasing consumption of sagebrush and for enhancing and maintaining biodiversity in the sagebrush-steppe.

To better understand how terpenes in sagebrush limit intake, we studied feeding behavior of sheep in the field, influence of sagebrush monoterpenes on regulation of intake in pens, and the feeding behavior …


Breeding Bird Communities Of Major Mainland Rivers Of Southeastern Alaska, Jim A. Johnson May 2003

Breeding Bird Communities Of Major Mainland Rivers Of Southeastern Alaska, Jim A. Johnson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Because of the scarcity of information for bird communities at the major mainland rivers of southeastern Alaska, the main objective of this study was to provide baseline information including distribution, status, and habitat associations of breeding birds.

I conducted a meta-analysis of all known reports (including the current study) conducted at major mainland rivers during the breeding season. I described bird species composition, distribution, abundance estimates, status, habitat associations, and guild membership for all birds recorded at 11 major mainland rivers. Based on incidental observations, 170 species were recorded by all studies. Of these, 134 species were known or suspected …


Modeling Habitat Quality For American Martens In Western Newfoundland, Canada, William A. Adair May 2003

Modeling Habitat Quality For American Martens In Western Newfoundland, Canada, William A. Adair

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The "Den Mother" marten habitat quality models were created to provide insight into American marten habitat selection behavior and to promote the recovery of the Newfoundland marten (Martes americana atrata) population. Although these objectives are typical of most wildlife habitat modeling projects, the marten's idiosyncratic habitat ecology and apparently intractable conflicts associated with timber harvesting motivated a unique, process-oriented approach to appraising landscapes. The Den Mother models used optimal decision-making principles to synthesize critical resources (den sites and foraging opportunities) and constraints (adverse thermal situations and exposure to predations) into a single hierarchical framework. The resulting spatially explicit, …


Rapid Effects Of 25-Hydroxyvitamin D3 On Calcium Uptake In Isolated Chick Enterocytes, Ruta Phadnis May 2003

Rapid Effects Of 25-Hydroxyvitamin D3 On Calcium Uptake In Isolated Chick Enterocytes, Ruta Phadnis

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

25-Hydroxyvitamin D3[25(OH)D3] is a metabolite of vitamin D3 that has long been considered to be an inactive precursor of the hormonally active metabolite 1,25- dihydroxyvitamin D3[l,25(OH)2D3]; consequently very few studies have addressed the potential biological activity of 25(OH)2D3. However, it is known that 100 nM 25(OH)2D3 increases calcium transport in the perfused duodenal loop of the chicken to 200% of controls within 20 minutes. The hypothesis of the current study is that 25(OH)2D3 may be a hormonally active metabolite …


Foraging Behavior And Habitat Use Patterns Of Brown Bears (Ursus Arctos) In Relation To Human Activity And Salmon Abundance On A Coastal Alaskan Salmon Stream, Anthony P. Crupi Jr. May 2003

Foraging Behavior And Habitat Use Patterns Of Brown Bears (Ursus Arctos) In Relation To Human Activity And Salmon Abundance On A Coastal Alaskan Salmon Stream, Anthony P. Crupi Jr.

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Over the past decade, demand for recreation has increased as part of Alaska's doubling growth in tourism. Along the Chilkoot River, near Haines, fishing and bear viewing have become increasingly popular. I investigated the ecological and behavioral interactions there between brown bears, salmon, and humans between 2000 and 2002. My objectives were to: (1) determine if specific human activities differentially influenced bear activity and foraging behavior, (2) identify temporal and spatial habitat use patterns, (3) evaluate brown bear response to natural and human disturbances and quantify related flight distances, (4) investigate changes in bear foraging behaviors in response to prey …


Rapid Actions Of 1,25-Dihydroxyvitamin D3 On Phosphate Uptake In Isolated Chick Intestinal Cells, Bin Zhao May 2002

Rapid Actions Of 1,25-Dihydroxyvitamin D3 On Phosphate Uptake In Isolated Chick Intestinal Cells, Bin Zhao

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

1,25-dihydroxyvitamin D3 [1,25(OH)2D3] has been shown to promote phosphate transport rapidly in the perfused duodenal loop, relative to controls, reaching treated/av basal at T = 40 min = 1.82 ± 0.42 and 1.11 ± 0.21, respectively.

By using isolated chick enterocytes, studies were undertaken to determine whether 1,25(OH)2D3 has a direct effect on isolated intestinal cells that is manifested by either enhanced uptake or extrusion of phosphate.

In time course studies, with 4- to 8-wk-old chicks, 32P uptake in enterocytes at 10 min after addition of test substance was 0%, 130%, …


Physiological Importance Of 1,25(Oh)2D3 Membrane-Initiated And Nuclear Actions In Chickens As A Function Of Growth, And Maturation In Male And Female Chickens, Birgitta Larsson May 2002

Physiological Importance Of 1,25(Oh)2D3 Membrane-Initiated And Nuclear Actions In Chickens As A Function Of Growth, And Maturation In Male And Female Chickens, Birgitta Larsson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

It is well established that l,25(OH)2D3 is a major regulator of calcium homeostasis. The steroid exerts its effects on its target organs by two mechanisms, a slow mechanism mediated by nuclear vitamin D receptors (nVDR), and a rapid mechanism mediated by the l,25(OH)2D3 membrane-associated rapid response steroid binding protein (l,25D3-MARRS bp). In this dissertation, the physiological relevance of membrane initiated steroid signaling was investigated by studying the correlation of age in male and female chickens with the magnitude of responses to l,25(OH)2D3 in duodena from 7-, 14-, 28-, and …


Coyote Foraging Ecology, Vigilance, And Behavioral Cascades In Response To Gray Wolf Reintroduction In Yellowstone National Park, T. Adam Switalski May 2002

Coyote Foraging Ecology, Vigilance, And Behavioral Cascades In Response To Gray Wolf Reintroduction In Yellowstone National Park, T. Adam Switalski

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Vigilance behavior can aid in the detection of predators and may also play a role in observation of conspecifics, in food acquisition, and in the prevention of kleptoparasitism. However, in most occasions, vigilance is most important as an antipredator function. Generally, factors that increase the risk of predation also increase the amount of vigilance. We examined whether the reintroduction of the large predator, the wolf, in Yellowstone National Park (YNP) would influence coyote vigilance and foraging ecology. From December 1997 to July 2000, we collected 1743 h of coyote activity budgets. Coyote home ranges occurred within wolf territories (termed high-use …


Factors Affecting The Harvest Vulnerability Of Trumpeter Swans, Heidi L. Tangermann May 2002

Factors Affecting The Harvest Vulnerability Of Trumpeter Swans, Heidi L. Tangermann

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Two species of swan are regularly found in Utah, tundra swans (Cygnus columbianus) and trumpeter swans (Cygnus buccinator). Tundra swans migrate through Utah. During the fall migration period they are hunted in the state under guidelines established by the United States Fish and Wildlife Service (USFWS). Trumpeter swans are occasional visitors to Utah during the same migration period. Because trumpeter swans are difficult to distinguish from tundra swans in flight, they 11 are at risk of being harvested during the swan hunt. In my thesis, I examine the factors that may influence trumpeter swan vulnerability to …


Movement Patterns Of Phrynosoma Mcallii And Phrynosoma Platyrhinos In Response To Substrate Texture, Daniel H. Foley Iii May 2002

Movement Patterns Of Phrynosoma Mcallii And Phrynosoma Platyrhinos In Response To Substrate Texture, Daniel H. Foley Iii

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

During the summers of 1999 and 2000 the apparent habitat partitioning of two species of sympatric horned lizards was investigated at the Barry M. Goldwater Bombing Range near Yuma, Arizona. The flat-tailed horned lizard, Phrynosoma mcallii, and the desert horned lizard, P. platyrhinos, overlap in range in portions of the Sonora desert in the southwestern United States. However, upon finer scale examination, it appeared that these horned lizards were partitioning the available habitat according to soil substrate texture. Phrynosoma mcallii appeared to be exclusively found in areas of fine, loose, wind-blown sands, in contrast to P. platyrhinos, …


Effectiveness Of Earthen Escape Ramps In Reducing Big Game Mortality In Utah, Mary L. Hammer May 2001

Effectiveness Of Earthen Escape Ramps In Reducing Big Game Mortality In Utah, Mary L. Hammer

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

One-way escape gates and earthen escape ramps are structures used to enable deer to exit the highway right-of-way along fenced roads. I compared the use of one-way escape gates and earthen escape ramps by mule deer on two highways in Utah to determine if deer exhibited a preference for either structure. Results showed that earthen escape ramps were used by mule deer 8-11 times more frequently than one-way gates. Highway mortality data suggest that the installation of the escape ramps likely reduced mortality of mule deer in both study locations, because we could not attribute reductions in mortality to decreased …


Reproductive Allocation And Survival In Grasshoppers: Effects Of Resource Availability, Grasshopper Density, And Parasitism, David Heath Branson May 2001

Reproductive Allocation And Survival In Grasshoppers: Effects Of Resource Availability, Grasshopper Density, And Parasitism, David Heath Branson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A major challenge in ecology is to understand intraspecific variation in life histories. Variation in resource availability can lead to differences in reproductive allocation and life histories. Grasshoppers are a good organism for the study of variation in life histories, since they exhibit life history plasticity in response to biotic and environmental factors. An optimality model for grasshoppers was developed that predicts optimal total allocation to reproduction and optimal effort-per-offspring as functions of resource availability and mortality. Relative allocation to reproduction is predicted to increase with resource availability, while relative allocation to survival declines. A resource-based trade-off between egg size …


Rangeland Resources Monitoring: Concepts And Practical Applications, Benny R. Bobwski May 2001

Rangeland Resources Monitoring: Concepts And Practical Applications, Benny R. Bobwski

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

How does one person manage and monitor a half million acres of rangelands towards a sustainable future? Through a journey that begins with the understanding of sustainability, I explore the monitoring concept, two of its applications, and summarize with an emphasis on the art and science of management. Sustainability is a concept that confuses many managers because it is so complex. However, if one considers adaptability as the complement to sustainability, and realizes that an adaptable organism is a sustainable organism, then a manager can relate because the emphasis shifts from that of stability for the future to that of …


The Relationship Of Milk Urea Nitrogen And Dhia Production Variables In Western Commercial Dairy Herds, Rachael G. Johnson May 2001

The Relationship Of Milk Urea Nitrogen And Dhia Production Variables In Western Commercial Dairy Herds, Rachael G. Johnson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Monthly individual cow DHIA test records (approximately 90,000) from 96 Holstein and Jersey herds from Utah, Idaho, and Montana were analyzed used the Mixed procedure in SAS to determine the relationships of milk production parameters to milk urea N (MUN). Records spanned two consecutive years ending December 2000. Means for Holsteins were 34.1 kg/d milk yield, 15.2 mg/dl MUN, 3.18% milk protein, 3.5% milk fat, and 280,000 somatic cell count. Mean MUN for Holsteins was lowest in fall (Oct.-Dec) and highest in winter and spring. Cows with highest milk protein percent (≥ 3.2%) had lowest MUN over all levels of …


Intensification In A Risky Environment: The Case Of Improving Private Grazing Land For Beef Production In Utah, Louise D. Sainsbury May 2001

Intensification In A Risky Environment: The Case Of Improving Private Grazing Land For Beef Production In Utah, Louise D. Sainsbury

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Utah ranchers commonly face risks to their livelihoods. The objective of this work was to determine if ranchers could make profitable improvements to private land forage given the combined threat of low beef prices, drought, and possible loss of public grazing.

We used linear programming (LINDO) to identify the most profitable solutions for private land investment with an 11-year simulation. Operations were divided into small, medium, and large size classes. Various forage improvements and public permits were options. Two phases of a beef price cycle (peak and trough) and 2 precipitation patterns (wet and drought) were combined as joint favorable …


Development Of A Bird-Avoidance Model For Naval Air Facility El Centro, California, Edward J. Zakrajsek May 2001

Development Of A Bird-Avoidance Model For Naval Air Facility El Centro, California, Edward J. Zakrajsek

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Bird strikes (collisions between birds and aircraft) pose a significant threat to aviation safety. For example, Naval Air Facility El Centro, California, lost an F-18 jet to a bird strike in October 1995. To help combat the bird-strike threat at Naval Air Facility El Centro, I developed a bird-avoidance model as a risk-management tool for the installation. It can be used to schedule flights at NAF El Centro and its two associated practice-bombing ranges during times of low-bird activity. I calculated bird-strike risks and published them in web-page format on both the installation's server and the USGS/Utah State University, College …


A Social Analysis Of Grazing Management On National Forest Lands: A Case Study In Catron County, New Mexico, Alexis S. Watts May 1999

A Social Analysis Of Grazing Management On National Forest Lands: A Case Study In Catron County, New Mexico, Alexis S. Watts

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The rural west in this country faces increased national pressure concerning the management of natural resources on public lands. Issues regarding natural resource management are becoming more important as they continue to affect rural communities and capture the attention of a variety of interest groups. Natural resource managers are increasingly required to consider social dimensions of resource use and management. Lack of consideration in these areas can lead to dissatisfied, and even hostile, local residents and interest groups. Often land managers face criticism from many groups at once as a result of management decisions.

This study analyzed a particular resource …


Influence Of Type Of Supplemental Carbohydrate On Ruminal Responses And Methane Output From Ruminants Consuming Low-Quality Forage, Raul J. Lira May 1999

Influence Of Type Of Supplemental Carbohydrate On Ruminal Responses And Methane Output From Ruminants Consuming Low-Quality Forage, Raul J. Lira

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In a completely randomized design with a factorial arrangement, three energy supplements and two species (cows and ewes) were evaluated in two identical experimental periods: gestation and lactation. The three supplement treatments were a control, barley, and sugar beet pulp (SBP). The basal diet was tall wheatgrass straw (5.52% CP).

Forage and total dry matter intake (FDMI and TDMI, respectively) interacted (P=.04) with species, supplements, and physiological stages.

An interaction of physiological stage and sampling time occurred for pH. Supplement and sampling time interacted for butyric acid proportion and total VFA concentration.

Diet digestibility displayed an interaction between …


Modeling Habitat Attributes Of Cavity-Nesting Birds In The Uinta Mountains, Utah: A Hierarchical Approach, Joshua J. Lawler May 1999

Modeling Habitat Attributes Of Cavity-Nesting Birds In The Uinta Mountains, Utah: A Hierarchical Approach, Joshua J. Lawler

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Birds may have the ability to view their environments at a wide range of spatial scales; accordingly, they may make habitat-selection decisions at multiple spatial scales. I investigated the implications of hierarchy theory and a landscape perspective on nest-site selection in cavity-nesting birds in the Uinta Mountains in northeastern Utah. I used three different approaches to address the concept of a multi-scaled nest-site selection process. First, I conducted an exploratory study in which I investigated nest-site selection at three spatial scales for Red-naped Sapsucker (Sphyrapicus nuchalis), Northern Flicker (Colaptes auratus), Tree Swallow (Tachycineta bicolor), and …


Nest Success Of Dabbling Ducks In A Human-Modified Prairie: Effects Of Predation And Habitat Variables At Different Spatial Scales, Jaime E. Jimenez May 1999

Nest Success Of Dabbling Ducks In A Human-Modified Prairie: Effects Of Predation And Habitat Variables At Different Spatial Scales, Jaime E. Jimenez

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Nest success of dabbling ducks in the Prairie Pothole region of North America has been declining for the past 40 years in parallel with declines in duck populations. Low nest success seems to result from the combination of an extremely fragmented breeding ground in a human-dominated landscape with an abundant and expanding community of generalist nest predators. Studies that examined variables associated with nest vulnerability to predation have produced contradictory results, likely because of simplistic approaches, lack of spatio-temporal replication, use of artificial nests, and the effect of confounding variables. I attempted to clarify the equivocal findings of previous studies …


Kokanee Fry Recruitment And Early Life History In The Lake Tahoe Basin, Christine K. Gemperle May 1998

Kokanee Fry Recruitment And Early Life History In The Lake Tahoe Basin, Christine K. Gemperle

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Lake Tahoe kokanee salmon have experienced decreasing mean adult size and fluctuating populations since 1970. We proposed to determine whether fish production was limited by spawning and incubation processes in Taylor Creek, or by growth constraints, or by mortality in the lake by studying egg-to-fry survival rates and early life history. Estimated egg-to-fry survival was 15. 9% for the 1994 brood year and 1.5% for the 1995 brood year. Egg-to-adult survival was 3.5% for the 1991 brood year and 5.9% for the 1992 brood year. Of the 35 possible survival scenarios, egg-to-fry survival was 7.5-20% and fry-to-adult survival (inlake phase) …


The Role Of Ammonia In Reproductive Inefficiency In High-Producing Dairy Cows Fed Excess Rumen Degraded Protein, Douglas Scott Hammon May 1998

The Role Of Ammonia In Reproductive Inefficiency In High-Producing Dairy Cows Fed Excess Rumen Degraded Protein, Douglas Scott Hammon

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The role of ammonia in reproductive inefficiency in early lactation dairy cows was studied in a series of experiments designed to determine the concentrations of ammonia in normal bovine follicular fluid (bFF), to determine the effects of ammonia on the bovine embryo during specific stages of development, and to test the hypothesis that elevated plasma urea nitrogen concentration is associated with elevated ammonia and urea nitrogen concentrations in the reproductive fluids.

In the first study, ammonia concentration in different size follicles and the effect of ammonia during in vitro maturation on embryo development were determined. Ammonia concentration in the bFF …


Rangeland Dynamics And Pastoral Development In The High Andes: The Camelid Herders Of Cosapa, Bolivia, Lita P. Buttolph May 1998

Rangeland Dynamics And Pastoral Development In The High Andes: The Camelid Herders Of Cosapa, Bolivia, Lita P. Buttolph

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Current models of rangeland system dynamics were evaluated in Cosapa, a pastoral community on the Bolivian altiplano. Two specific models were tested: the "equilibrium" model, which assumes biotic interactions dominate rangeland dynamics and lead to system stability, and the "nonequilibrium" model, in which stochastic, abiotic factors control systems such that equilibrium is never attained. A livestock development project (called "Project Alpaca") working in the community was then assessed in terms of how its assumptions of system dynamics compared with empirical findings. The goal of Project Alpaca was to increase incomes for camelid (i.e., llama and alpaca) herders on the …


Seed Dispersal By Livestock: A Revegetation Application For Improving Degraded Rangelands, Ferhat Gokbulak May 1998

Seed Dispersal By Livestock: A Revegetation Application For Improving Degraded Rangelands, Ferhat Gokbulak

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A series of experiments was conducted to: 1) investigate how feeding cattle with different amounts of different-sized seeds affects seed passage rate through the digestive tract, and the germinability of passed seeds; 2) examine how the location of seeds in dungpats of different thicknesses influences seedling emergence, development, and survival in cattle dungpats; and 3) characterize seedling emergence in naturally and artificially deposited cattle dungpats. Three perennial, cool-season grasses, bluebunch wheatgrass [Psuedoroegneria spicata (Pursh) A. Love], Sandberg bluegrass (Poa secunda Presl.), and 'Hycrest' crested wheatgrass [Agropyron desertorum (Fisch. ex Link) X A. cristatum (L.) Gaert.], were used …