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Mechanisms Of Population Regulation In Confined Colonies Of Peromyscus Maniculatus (Wagner) And The Response To Exploitation, Donna Corn Olsen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Wild-trapped and laboratory-reared Peromyscus maniculatus (Wagner) were raised as confined colonies indoors with various stocking densities ranging from 0.026 to 0.100 mice per sq. ft. in pens of 40, 77, and 154 sq. ft. The animals were individually tagged and all pens were censused at weekly or semi-monthly intervals to record animals present, body weights, food consumption, and overt reproductive condition. At the termination of each experiment, all mice were necropsied and organ weights of gonads and adrenals recorded. Histological sections were made of the testes and ovaries. Half the colonies were subjected to density-independent exploitation by removal of 50% …

Habitat Selection By Large Wild Ungulates And Some Aspects Of The Energy Flow In A Sub-Tropical African Savanna Woodland Ecosystem, Stanley M. Hirst

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A study of habitat selection by large wild ungulates was carried out on a 50 cm² area in the sub-tropical Lowveld region of eastern Transvaal province, South Africa. Estimations were made of herbaceous forage net productivity and ungulate secondary productivity on the same area.

Fourteen vegetation types, varying in composition and structure from open savanna to dense woodland, were delineated by association analysis. Structural and vegetational characteristics which were considered to influence ungulate distribution were measured within each vegetation type.

The study area supported resident populations of seven ungulate species during the wet season; drv season densities were higher …

Economics Of Carry-Over Production And Increased Grazing Season Length Due To Range Fertilization, Paul W. Mccormick

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This paper entails the economic and biological interpretation of the response of rangeland grasses to nitrogen fertilization. Six sites throughout Utah received graduated rates of fertilizer. The coefficients of the production function
Y = a + bN - cN²
were identified.

An initial production and a carry-over response were identified on sites receiving greater than ten inches of annual precipitation. Optimum fertilization rates may be identified by equating the marginal physical product to the ratio of the price of nitrogen to the price of the forage.

Forage response to nitrogen is reflected strongly in the early growth response in …

Fish Production And Movements In The Lower Logan River, Utah, Eric P. Bergersen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Following the abatement of domestic sewage pollution xii in the lower Logan River , the fish population was investigated in terms of abundance, growth, fecundity, production, mortality, age class structure, species diversity, distribution and movements during 1970 and 1971.

Three general groupings of fish were identified in the study area on the basis of species composition, abundance and distribution using a cluster analysis technique. These were located in 1) the tributary stream (7-Mile Creek) which previously transported sewage to the river and 2) above and 3) below 7-Mile Creek in the main stream of the Logan River. A "transition" population …

Impact Of The Black-Tailed Jackrabbits (Lepus Californicus) On Vegetation In Curlew Valley, Northern Utah, Mark Westoby

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The interrelations of black-tailed jackrabbits and the desert-shrub vegetation on which they were feeding were studied in Curlew Valley, Northern Utah. The vegetation was described as a three-cornered continuum, the corners being types dominated respectively by Artemisia tridentata, Atriplex confertifolia, and Sarcobatus vermiculatus.

Jackrabbit diet was studied by microscopic analysis of plant fragments in stomachs from shot animals. The method was inaccurate, apparently because the ratio of identifiable tissues to all ingested tissues was very low, and varied between plant taxa, and seasonally. This problem seems intractable for desert shrub vegetation.

The diet was similar to that …

Effects Of Exercise On Serum Lactate Dehydrogenase Activity Of Catchable-Size Hatchery Rainbow Trout, Salmo Gairdneri, Gerlad T. Klar

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Effects of exercise and the relative condition of exercised fish were viii evaluated for two strains of rainbow trout. Circular tanks fitted with a paddle were used to continuously exercise the fish and a stamina tunnel was used to evaluate the condition of exercised trout. Trout were exercised continuously at one fish-length per second and one-half fish length per second. Serum LDH activity in Shephard-of-the-Hills (Missouri) rainbow trout acclimated to 10 C increased two fold during the first four days of exercise. Serum LDH activity returned to control levels by the tenth day of exercise. Serum LDH activity in Shephard-of-the-Hills …

Trout Movements In A Small Mountain Stream, Thomas Mark Twedt

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Five groups of 400 hatchery rainbow trout, (Salmo gairdneri), were stocked in a small, mountain stream at 3-week intervals from June to September, 1972. A fish trap captured any fish moving out of a 500 m study section.

Fish began moving at high levels during the first day of each stocking and continued at high rates for 5-8 days (Early Phase), after which movement decreased to low levels for 6-9 days (Late Phase). Early Phase fish moved primarily at night, possibly due to their disoriented state and high subjectivity to stream conditions. Fish moving during Late Phase did …

The Relationship Of Climatic Factors To Grazing Activities Of Cows On Winter And Spring Ranges, Benton M. Smith

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this research was to investigate the effects of climatic variations upon the daily activities of grazing cattle. The activities of individual cows on a partially seeded salt desert shrub range were observed and recorded during three grazing periods. Two of the periods were during consecutive winters and the other during the spring. Climatic variations during the second winter period were quantified and compared to changes in the daily activity patterns of the cattle.

Distinctly different daily routines of cattle activities were evident for the winter and spring seasons. In the spring, the cattle grazed, traveled, and drank …

A Computerized Performance Record Keeping System For Beef Cattle In Utah, John J. Pierce

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A computer program was developed at Utah State University (USU) to aid in obtaining a more complete individual performance record keeping system for beef cattle in Utah. Some computer programs for beef cattle records presently exist but a program was needed that was readily available to the USU animal science extension and resident staff.

The program was written in FORTRAN for use on the Burrogh 6700 computer located at the Utah State University Computer Center. It was designed to read input data for individual animals, perform various calculations (i. e. days of age, adjusted weaning weight and weaning weight ratio), …

An Evaluation Of Stress Induced Mortality Of Stocked Catchable-Sized Rainbow Trout In Temple Fork Of The Logan River, Robert Earl Gresswell

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The level of stress imposed by population pressure, handling and live transportation on planted catchable-sized rainbow trout in a northern Utah stream was examined. Production of adrenocorticotrophin, as measured by interrenal ascorbic acid and serum cortisol levels, did not occur in transported or planted fish.

Dead or moribund fish collected from stream or live boxes comprised 13 percent of the 2,000 fish planted. Aeromonas salmonicida, the causative agent of furunculosis, was isolated from 41 percent of 106 moribund fish sampled. In addition, 39 percent of the samples exhibited bacterial growth other than A. salmonicida. Apparently, handling, transportation, and planting did …

Factors Affecting Feeding Habits Of Sheep Grazing Foothill Ranges Of Northern Utah, Farid D. Iskander

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

An experiment was designed to study the effects of forage availability, season and intensity of grazing, and distribution and behavior of sheep on their forage preferences. Three grazing periods of 15 days each were used to study the effect of season. Each grazing period included a heavy and a moderate stocking intensity. Pastures were divided by a grid into 30.48 m x 30.48 m compartments. Each compartment was sampled for botanical composition of available herbage prior to and after grazing. Esophageally fistulated sheep were allowed to graze freely and positions of individual sheep with respect t o compartments were recorded …

Overwinter Mortality Of Trout In Temple Fork Of The Logan River, Daniel Richard Cerven

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The objectives of this study were to determine the mortality rates of trout in Temple Fork of the Logan River during the winter of 1970-1971 and to identify factors related to trout mortality.

Trout in seven 100-m sections of the 7 3-km stream were sampled by electroshocking in October, December, February, and April. Captured trout were weighed measured and tagged or fin-clipped. Scale samples were taken for age determinations and the fish were returned to the creek.

Water temperature, snow cover, and anchor ice were monitored.

Three species of trout were found in Temple Fork: brown, rainbow, and cutthroat trout. …