Life Sciences Commons^™

Effects Of Grazing Vs. Resting On Soil Chemistry And Plant Community Dynamics For The Central Coast Of California In 2012, Jessica Combs

Animal Science

No abstract provided.

Effects Of Long-Term Cattle Grazing And Woody Plant Encroachment On Soil Microbial Communities At The Santa Rita Experimental Range, Arizona, Cody Burton, Steven Archer, Rebecca L. Mcculley

Plant and Soil Sciences Presentations

Livestock grazing is considered a key driver of woody plant encroachment in dryland ecosystems worldwide. Woody plant establishment in these systems creates “islands of fertility,” in part by modifying erosional processes such that soil and plant litter are deposited beneath the shrub canopy, creating a nutrient rich soil/litter matrix that supports enhanced soil microbial biomass pools. In this study, we utilized a long-term grazing exclosure (>80 yrs) at the Santa Rita Experimental Range south of Tucson, Arizona and phopsholipid fatty acid analysis to quantify livestock grazing effects on soil microbial communities associated with the complex vegetative mosaic that characterizes …

Idiosyncratic Responses Of Seagrass Phenolic Production Following Sea Urchin Grazing, Latina Steele, John F. Valentine

Biology Faculty Publications

While chemical defenses can determine plant persistence in terrestrial ecosystems and some marine macroalgae, their role in determining seagrass persistence in areas of intense grazing is unknown. As a first step toward determining if concentrations of feeding deterrents in seagrasses increase following herbivore attacks, we conducted 4 experiments using a common macrograzer (sea urchin Lytechinus variegatus) and 2 phylogenetically divergent seagrass species (Thalassia testudinum and Halodule wrightii). Macrograzer impacts on production of phenolic acids and condensed tannins varied somewhat idiosyncratically with season, urchin density, and distance from urchin damage. In general, phenolic concentrations were higher in both turtlegrass and shoalgrass …

Bulletin No. 385 - Comparitive Nutritive Value And Palatability Of Some Introduced And Native Forage Plants For Spring And Summer Grazing, C. Wayne Cook, L. A. Stoddart, Lorin E. Harris

Christopher Cook

From 1952 to 1954 studies were conducted on foothill ranges of central Utah to determine the forage production, palatability, and nutritive value of some of the more important native and introduced species used for spring and summer grazing.

Plants studied were four introduced wheatgrasses (crested, tall, pubescent, and intermediate) , four native grasses (western wheatgrass, beardless wheatgrass, squirreltail grass, and Indian ricegrass), and two introduced annual forbs (Russian-thistle, and smother weed).

Field digestibility trials were conducted to determine the nutrient content by the lignin-ratio technique. In addition, both sheep and cattle preferences were studied on areas where both introduced and …

Maternal Environment And Fescue Cultivar Effects On Growth, Development, And Fertility Of Beef Heifers, Jennifer Denyse Patterson

Graduate Theses and Dissertations

Eighty Brahman-influenced cows (5.6 BCS) were assigned to graze common bermudagrass (CB) or toxic tall fescue (E+) during a 60-d breeding season. Body condition (BC) was assessed at d 0, 30, and 60 of breeding season. Cows were managed to achieve marginal (4.2 BCS) or good (6.3 BCS) BC during last trimester. Heifer birth and weaning (WW; 7 to 8 mo) weights were recorded. The Angus sired heifers were weighed and randomly assigned to E+ or non-toxic (Novel) tall fescue at 9 to 10 mo of age for 190d. Heifer weight, growth data, and antral follicle count (AFC) were collected …

Avian Habitat Response To Grazing, Haying, And Biofuels Production In Native Warm-Season Forages In The Mid-South, Jessie Lee Birckhead

Masters Theses

Declines in grassland birds have been attributed to loss of habitat, habitat degradation, and changes in land management. In the Mid-South, pasture and hayfield management has focused on maintaining dense stands of non-native forages that do not provide suitable vegetative structure for grassland birds or northern bobwhite. Native warm-season grasses have been promoted for livestock forage and biofuels feedstock. However, little information exists on how these practices affect habitat for grassland songbirds or northern bobwhite in the Mid-South. We conducted a study of two cattle grazing treatments, two hay harvest treatments and a biofuels harvest treatment on vegetative structure for …

Monitoring Standing Herbage Of Mid-Grass Prairie On The Fort Pierre National Grassland, South Dakota, Daniel W. Uresk

The Prairie Naturalist

Monitoring vegetation with a modified Robel pole on the Fort Pierre National Grassland was evaluated for combined shallow clay and loamy overflow ecological sites (dominated by warm-season grasses), and for clayey ecological sites (dominated by cool-season grasses). My objectives were to 1) develop a relationship between visual obstruction readings (VOR) and standing herbage, 2) provide guidelines for vegetation monitoring, and 3) evaluate vegetation monitoring during the growing season for clayey ecological sites. The relationship between visual obstruction readings and standing herbage was linear and regression coefficients were highly significant (P < 0.001) for both ecological types. Cluster analyses for shallow clay and loamy overflow ecological sites grouped the VOR and standing herbage (kg•ha-1) into 4 resource categories. Monitoring with 4 transects will provide adequate information to estimate standing herbage within 259 ha (1 section). Three resource categories (VOR + herbage) for clayey ecological sites were defined by cluster analyses. Monitoring with 4 transects was determined to provide reliable estimates of standing herbage. July validation of vegetation with the developed clayey ecological site model will provide reliable monitoring of standing herbage from July through November for this ecological site.

Sp731-C Grazing Native Warm-Season Grasses In The Mid-South, Patrick Keyser, Gary Bates, John Waller, Craig Harper, Elizabeth Doxon

Animals/Livestock

No abstract provided.

Effects Of Management Strategies And Molecular Breeding Values On Cattle Performance And Carcass Traits, Benjamin Collins Williamson

Graduate Theses and Dissertations

Forty-eight Gelbvieh x Angus steers (265 ¡À 40 kg) were utilized to determine the relationships among molecular breeding values (MBV), steer performance, and carcass traits. Body weight (BW), hip height (HH), hip width (HW), exit velocity (EV; rate at which steers exited the squeeze chute and traversed 1.8 m) and body ultrasound measurements of steers were recorded at d 0, 93 and 154 of grazing mixed stockpiled endophyte-infected and -free tall fescue. Tissue samples were collected for genomic profiling (Igenity, Merial Limited, Duluth, GA). Steers were transported to the Oklahoma State U fed for 159 d, harvested and carcass parameters …

Global Patterns In The Impact Of Marine Herbivores On Benthic Primary Producers, Alistair G.B. Poore, Alexandra H. Campbell, Ross Coleman, Graham J. Edgar, Veijo Jormalainen, Pamela L. Reynolds, Erik E. Sotka, John J. Stachowicz, Richard Taylor, Mathew A. Vanderklift, J. Emmett Duffy

VIMS Articles

Despite the importance of consumers in structuring communities, and the widespread assumption that consumption is strongest at low latitudes, empirical tests for global scale patterns in the magnitude of consumer impacts are limited. In marine systems, the long tradition of experimentally excluding herbivores in their natural environments allows consumer impacts to be quantified on global scales using consistent methodology. We present a quantitative synthesis of 613 marine herbivore exclusion experiments to test the influence of consumer traits, producer traits and the environment on the strength of herbivore impacts on benthic producers. Across the globe, marine herbivores profoundly reduced producer abundance …

Influence Of Habitat Heterogeneity On Small Mammals In The Central Platte River Valley, Nebraska, Justin D. Anderson

Master's Theses

Although the loss of prairie is substantial across the extent of its historic range, large portions of native rangeland still remain throughout Nebraska. It is critical that resource managers and private landowners manage rangelands in a manner that will enhance ecosystem integrity by using techniques that provide disturbance regimes. Heterogeneity based management, such as patch-burn grazing and rest-rotation grazing, can be used as a conservation tool to increase biodiversity within management units and at a landscape level. Heterogeneity-based management has received much attention in the literature within the past decade, but there has been little focus on how these management …

Grasslands And Carbon: Processes And Trends, Rebecca L. Mcculley

Plant and Soil Sciences Presentations

Grasslands, which make up 30% of the U.S. land surface, store significant amounts of carbon belowground in roots and soils. Learn how disturbances such as drought, grazing, fire and tillage can significantly impact the grassland carbon balance.

Dr. Rebecca McCulley of the University of Kentucky, Dept. of Plant & Soil Sciences, talks about grasslands and the way they store and process carbon. Grasslands make up about 30 percent of the North American surface. Grasslands differ from forests in many ways, but from a carbon perspective they store a much greater proportion of the carbon than they take in in any …

Dried Distillers Grains As A Substitute For Grazed Forage, L. A. Stalker, T. J. Klopfenstein, Walter H. Schacht, J. D. Volesky

Department of Animal Science: Faculty Publications

A 2-yr study evaluated effects of feeding dried distillers grains (DDG) to yearlings grazing native range at greaterthan- recommended stocking rates on BW gain, grazed forage quality, and forage disappearance. Thirty-six paddocks were assigned randomly to 1 of 3 treatments: 1) control, stocked at a moderate stocking rate (1.48 animal unit months/ha in yr 1, 1.06 animal unit months/ha in yr 2) with no DDG; 2) double stocked, in which stocking rate was exactly twice the control with no DDG; and 3) double stocked with 2.27 kg/d (DM) of DDG per animal. Six paddocks per treatment replication were grazed in …

Extended Grazing: A Detailed Analysis Of Irish Dairy Farms, D. Läpple, T. Hennessy, M. O'Donovan

Farm Animal Husbandry Collection

Profitability and factors affecting grazing season length were econometrically analyzed using a representative sample of Irish dairy farms. The objective of this study was to explore what potential exists on Irish dairy farms to extend the grazing season and to quantify the possible economic benefits that result from lengthening the grazing season. Regression results indicate that location factors affect the length of the grazing season, but even when physical factors are controlled, farmer characteristics, such as education, also affect the grazing season length. The results of a panel data analysis show that significant cost reductions can be achieved by extending …

Effects Of Ungulate Herbivory On Aspen, Cottonwood, And Willow Development Under Forest Fuels Treatment Regimes, Bryan A. Endress, Michael J. Wisdom, Martin Vavra, Catherine G. Parks, Brian L. Dick, Bridgett J. Naylor, Jennifer M. Boyd

USDA Forest Service / UNL Faculty Publications

Herbivory by domestic and wild ungulates can dramatically affect vegetation structure, composition and dynamics in nearly every terrestrial ecosystem of the world. These effects are of particular concern in forests of western North America, where intensive herbivory by native and domestic ungulates has the potential to substantially reduce or eliminate deciduous, highly palatable species of aspen (Populus tremuloides), cottonwood (Populus trichocarpa), and willow (Salix spp.). In turn, differential herbivory pressure may favor greater establishment of unpalatable conifers that serve as ladder fuels for stand-replacing fires. The resulting high fuel loads often require silvicultural fuels reductions …

A Synoptic Review Of U.S. Rangelands A Technical Document Supporting The Forest Service 2010 Rpa Assessment, Matthew Clark Reeves, John E. Mitchell

USDA Forest Service / UNL Faculty Publications

The Renewable Resources Planning Act of 1974 requires the USDA Forest Service to conduct assessments of resource conditions. This report fulfills that need and focuses on quantifying extent, productivity, and health of U.S. rangelands. Since 1982, the area of U.S. rangelands has decreased at an average rate of 350,000 acres per year owed mostly to conversion to agricultural and residential land uses. Nationally, rangeland productivity has been steady over the last decade, but the Rocky Mountain Assessment Region appears to have moderately increased productivity since 2000. The forage situation is positive and, from a national perspective, U.S. rangelands can probably …

Energy And Water Use By Invasive Goats (Capra Hircus) In An Australian Rangeland, And A Caution Against Using Broad-Scale Allometry To Predict Species-Specific Requirements, Adam J. Munn, C E. Cooper, B Russell, T J. Dawson, S R. Mcleod, S K. Maloney

Faculty of Science - Papers (Archive)

Feral goats (Capra hircus) are ubiquitous across much of Australia's arid and semi-arid rangelands, where they compete with domestic stock, contribute to grazing pressure on fragile ecosystems, and have been implicated in the decline of several native marsupial herbivores. Understanding the success of feral goats in Australia may provide insights into management strategies for this and other invasive herbivores. It has been suggested that frugal use of energy and water contributes to the success of feral goats in Australia, but data on the energy and water use of free-ranging animals are lacking. We measured the field metabolic rate …

Grazing On Synechococcus Spp. By The Red-Tide Dinoflagellate Karenia Brevis: Implications For Bloom Dynamics In The Gulf Of Mexico, Leo A. Procise

OES Theses and Dissertations

Karenia brevis, the toxic dinoflagellate responsible for massive red tides in the Gulf of Mexico (GOM), causes fish kills, shellfish poisoning, and acute respiratory irritation in humans. Bloom initiation and maintenance have been linked to the physical environment as well as various nutrient input mechanisms. To date, efforts to quantify nitrogen (N) sources fueling K. brevis blooms in the GOM have not included mixotrophic grazing although many dinoflagellates, including K. brevis, are known to be capable of mixotrophy. This dissertation reports field and laboratory results demonstrating that natural bloom populations and K. brevisisolates from the West Florida …