Digital Commons Network^™

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 …

Effects Of Uv-B Radiation On Egg And Larval Golden Shiner (Notemigonus Crysoleucas) In Castle Lake, California, Jai-Ku Kim

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

I studied effects of UV-B radiation on egg and larval golden shiner (Notemigonus crysoleucas) in Castle Lake, California, USA. To compare egg hatching and survival of larval golden shiner, I exposed eggs and larval fish to three different UV-B treatments, low UV-B (4% UV-B), high UV-B (92% UV-B), and ambient (100% UV-B). The egg experiment was conducted in lake and pond water, whereas proto- and mesolarval stage experiments were conducted in lake water only.

High and ambient UV-B radiation affected the hatching rate of golden shiner eggs. The mean hatching rate was 13% lower in high UV-B, and …

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) …

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 …

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 …

Protein Production In The Milk Of Genetically Engineered Animals, Katherine M. Bates

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

There are numerous proteins that have potential uses in commercial and scientific applications that are not utilized to their full potential. this is partly because it is not economically feasible to isolate some of these proteins from their natural sources or to produce them using bacterial fermentation methods. The purpose of this research was to target recombinant protein expression to the mammary glands of genetically engineered or transgenic animals. Foreign protein expression has been achieved in the mammary glands of rabbits, sheep, cows, and swine. By using a strong mammary gland promoter and signal peptide fused to the protein, it …

Livestock Watering Practices In The Moroccan Pre-Sahara: Their Effects On Water And Nutrient Metabolism Of Sheep In Different Body Conditions, El Mostafa Darfaoui

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A field survey and a metabolism experiment were conducted to study livestock watering practices in the Moroccan Pre-Sahara and their changes with drought extent, season, ecological zone, pastoral system, and herd size. The metabolism experiment was designed to determine effects of once per 2 days (ID), once daily and twice daily drinking frequencies, and high and low body conditions on water and nutrient utilization by sheep fed high- and low-quality diets.

The way herds are managed in this region exposes all sex and age categories of animals to food and water shortages during annual dry seasons and occasional droughts. Livestock …