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2007

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Articles 61 - 90 of 3598

Full-Text Articles in Life Sciences

Heifer Development – Then And Now, Richard N. Funston, Jeremy Martin, Andy Roberts Dec 2007

Heifer Development – Then And Now, Richard N. Funston, Jeremy Martin, Andy Roberts

Range Beef Cow Symposium

Studies in numerous species provide evidence that diet during development can partially control physiological changes necessary for puberty (Frisch, 1984). Energy balance or plane of nutrition influences reproductive performance in heifers and cows (Short and Adams, 1988; Butler and Smith, 1989; Swanson, 1989; Randel, 1990; Robinson, 1990). Numerous studies have reported inverse correlations between post-weaning growth rate and age at puberty (Wiltbank et al., 1966, 1969, 1985; Short and Bellows, 1971; Arije and Wiltbank, 1971; Ferrell, 1982), and pregnancy rates in heifers were shown to be dependent upon the number displaying estrus prior to or early in the breeding season …


Nutrition During Gestation And Fetal Programming, K. A. Vonnahme Dec 2007

Nutrition During Gestation And Fetal Programming, K. A. Vonnahme

Range Beef Cow Symposium

Historically, considerable efforts have been made to understand how nutrition impacts health and productivity during the postnatal period. While maternal nutrition during pregnancy plays an essential role in proper fetal and placental development, less is known about how maternal nutrition impacts the health and productivity of the offspring. Indeed, the prenatal growth trajectory is sensitive to the direct and indirect effects of maternal dietary intake from the earliest stages of embryonic life when the nutrient requirements for conceptus growth are negligible (Robinson et al., 1977). Not only is neonatal health compromised, but the subsequent health may be “programmed” as offspring …


Preparing Calves For The Feedlot, Daniel U. Thomson Dec 2007

Preparing Calves For The Feedlot, Daniel U. Thomson

Range Beef Cow Symposium

Evidence based medicine is a balancing act between data and experience (Apley and Thomson, 2003). Decision making with just experience and no data has been termed “wizardry.” This would be similar as to saying we used drug A last year and they all died. This year we used drug B and they all lived. Great! Scientists and statisticians need not apply to work in this environment. The friendly drug representative that sells drug B is the expert. Paralyzed indecision is using only data with no experience to make decisions. This is the art of trying to fix problems from a …


The Immune System And Recovery From Sickness In Cattle, Gordon W. Brumbaugh Dec 2007

The Immune System And Recovery From Sickness In Cattle, Gordon W. Brumbaugh

Range Beef Cow Symposium

Ideally, all diseases could be prevented and beef animals on-feed would finish healthy and with the highest quality of meat. That isn’t realistic for most diseases. In spite the best efforts, some animals will become sick and require treatment. Calves with bovine respiratory disease (BRD) that required more than one treatment had decreased quality of meat and economic returns than did calves that did not develop BRD or responded after one treatment. (Hicks, 2006; McNeill, 1999; Wagner, et al., 2006) Calf-hood diseases in heifer calves had measurable effects on maternal performance for several years. (Waltner-Toews et al., 1986; van der …


I. Basic Principles Used In The “Sandhills Calving System” And How They Apply To Other Production Environments, David R. Smith Dec 2007

I. Basic Principles Used In The “Sandhills Calving System” And How They Apply To Other Production Environments, David R. Smith

Range Beef Cow Symposium

Diarrhea is one of the most likely reasons young beef calves become sick or die.(45) Besides its detriment to calf health and well-being, calf scours is costly to cattle producers due to poor calf performance, death, and the expense of medications and labor to treat sick calves. (3, 41) In addition, catching and treating young calves puts herd owners and their employees at risk of injury, and many producers become disheartened after investing long hours to treat scouring calves during an already exhausting calving season.

Calf scours is a complex disease, with many interrelated causes.(1, 2, 37) Agent, host, and …


Ultrasound-Based Selection: Pitfalls And Rewards, Steve Paisley, Chris Loehr, Frances Niemala Dec 2007

Ultrasound-Based Selection: Pitfalls And Rewards, Steve Paisley, Chris Loehr, Frances Niemala

Range Beef Cow Symposium

Ultrasound has become widely used by the seedstock industry as a selection and evaluation tool. Ultrasound estimates of Ribeye Area, or REA, Intramuscular fat, or %IMF (marbling), and Rump Fat have been used to develop several EPD’s for many breed associations. Despite widespread use by seedstock producers, there is still some apprehension by commercial producers. Additionally, the use of ultrasound for commercial herd replacement decisions, used by some producers, is worth discussing. There are both benefits, as well as cautions, to using ultrasound generated information in a commercial beef herd.


Gene-Testing For Production And Carcass Traits: What Does It Mean To A Rancher?, Robert L. Weaber Dec 2007

Gene-Testing For Production And Carcass Traits: What Does It Mean To A Rancher?, Robert L. Weaber

Range Beef Cow Symposium

Marker assisted selection (MAS) is a process that enables the accurate selection of specific segments of DNA that are associated with a measurable difference or effect on a complex trait, like weaning weight or marbling score. MAS can be an effective way to increase or decrease the frequency of specific DNA sequences in a population. It is important to note that many genes control complex traits, like marbling or tenderness; they are polygenic in nature. Markers for specific variations in DNA sequences are available for only a few genes that contribute to marbling or tenderness. There are many other ‘unmarked’ …


Genetic Information Made Easy: How To Sort Through The Chaff To Find The Nuggets, Willie Altenburg Dec 2007

Genetic Information Made Easy: How To Sort Through The Chaff To Find The Nuggets, Willie Altenburg

Range Beef Cow Symposium

Altenburg Super Baldy Ranch has been a family owned business for nearly 30 years. The yearly calendar of events may help explain the philosophy and the cattle. The 150 head cowherd is made up of Simmental and Angus, both black and red. They are summered on large, native grass pastures on the Soapstone Grazing Association (20 acres per cow) on the Colorado/Wyoming border. They and their calves are trailed horseback there each June, a 15 mile drive crossing two ranches and using the help of friends and neighbors. After weaning and preg check, the cows are trailed home to graze …


The Value Of Heterosis In Cow Herds: Lessons From The Past That Apply To Today, Matthew L. Spangler Dec 2007

The Value Of Heterosis In Cow Herds: Lessons From The Past That Apply To Today, Matthew L. Spangler

Range Beef Cow Symposium

Beef cattle producers are currently faced with a multitude of challenges. The traditional cattle cycle appears to have deviated from conventional wisdom, in part because of increasing grain prices due to a biofuels ‘industry’ that has become a competitor for grain resources that the U.S. fed cattle industry has grown dependent upon. A suite of genetic tools have been provided, or are in the works, to address issues such as feed efficiency, fertility, and longevity; along with more traditional EPDs for production and carcass/ultrasound traits. Established EPDs have proven to be very successful at allowing producers to take advantage of …


Monitoring Grazing Lands: How, Why, When, What?, Paul J. Meiman Dec 2007

Monitoring Grazing Lands: How, Why, When, What?, Paul J. Meiman

Range Beef Cow Symposium

Monitoring is the orderly collection, analysis and interpretation of information and data used to make short- and long-term management decisions (Wyoming Range Service Team 2001). Therefore, monitoring is an evaluation process used by animal and natural resource managers to help determine how rangeland or pasture systems respond to management (Holechek et al. 2004). The identification of monitoring as a process is crucial and suggests a number of important considerations. Monitoring has multiple components. This process includes not just collection, but also analysis and interpretation of information and data. Simply collecting information and data (for example taking lots of pictures) does …


Working With Federal Agencies To Develop Win-Win Programs For Ranchers And The Public, Eric Peterson Dec 2007

Working With Federal Agencies To Develop Win-Win Programs For Ranchers And The Public, Eric Peterson

Range Beef Cow Symposium

In the west, producers often find themselves working with a federal agency in some sort of partnership. In public land areas, the most common relationship revolves around United States Forest Service (USFS) or Bureau of Land Management (BLM) grazing permits. However, there are many producers, far removed from USFS or BLM lands, who are involved in some sort of relationship with governmental agencies. The Natural Resource Conservation Service springs to mind as an agency which many producers partner with. Others include Farm Service Agency, state wildlife management agencies, state lands agencies, Bureau of Reclamation, Fish and Wildlife Service, to name …


Delivery Of Supplements Of Rangelands, Kenneth C. Olson, Adele Harty Dec 2007

Delivery Of Supplements Of Rangelands, Kenneth C. Olson, Adele Harty

Range Beef Cow Symposium

Supplementation of cows grazing rangelands is often beneficial to overcome nutrient deficiencies or imbalances. However, supplemental feeds and their delivery to the cow herd are expenses and thus supplementation decisions should be carefully made to ensure that costs are minimized and benefits in terms of cow performance exceed supplementation costs. When supplementing cows, there are questions that producers should ask themselves to determine the best management practices to provide the most cost effective supplement program for their operation. The first among these is the type of supplement to be provided in terms of whether it will provide the correct nutrient …


Creating And Being Rewarded For Value In Calves, Tim Davis Dec 2007

Creating And Being Rewarded For Value In Calves, Tim Davis

Range Beef Cow Symposium

A. The discovery of BSE that day may very well have changed the way the US beef industry conducts business evermore.

B. Consumers, international as well as domestic, are requiring more standards and better verification behind marketing claims.

C. The Agriculture Marketing Service (AMS) of USDA initiated a process to ensure companies and their suppliers could verifiably deliver products to consumers that met their respective product claims.


Creating Value And Preserving Margin With Commercial Cows, Jim Lerwick Dec 2007

Creating Value And Preserving Margin With Commercial Cows, Jim Lerwick

Range Beef Cow Symposium

If the object of the game is to do what one enjoys while making outstanding margin, we in the cow business have enjoyed one of the greatest opportunities in decades. Even though drought has made it an unequal distribution, and disease and politics have added considerable confusion, turning grass and other feed stuffs into marketable calves has been good. We have had challenges to enhance value for specific markets with new technologies. We have seen our aged cow and bull markets influenced heavily by border issues as well as premium meat markets disrupted by embargos and restrictions. Feed price has …


Marketing For Added Value, Glenn Smith Dec 2007

Marketing For Added Value, Glenn Smith

Range Beef Cow Symposium

“Value Added Calf” is a phrase that has been around the beef cattle industry for several decades. In short, value added marketing is taking a commodity and creating additional value through management practices, and then marketing that commodity in such a way as to be paid for the additional value created. Although producers may have taken a number of steps to create that added value, it is all for naught if the product is not marketed in such a way as to capture that additional value.

Added value can be created through quite a number of production steps. Breed selection …


Woody Invasive Plant Species Occurrence And Abundance As, Jyoti Patnaik Dec 2007

Woody Invasive Plant Species Occurrence And Abundance As, Jyoti Patnaik

All Theses

The spread of invasive plants is one of the most challenging ecological problems in the 21st century, causing a $35 billion loss per year to the economy in the United states alone. More than 85% of woody invasive species were introduced originally for ornamental and landscape use. As a result, over the last few decades, perennial woody invaders have appeared in fence rows, rights-of-way, old fields, understories, and the canopies of eastern forests of the United States. Besides the information about the geographical distribution, general biological characteristics, and response to herbicides, very little information is available on the occurrence and …


Analysis Of Hg And Stable Isotope Concentrations In Bald Eagle Feathers From The Great Lakes And Voyageurs National Park, Minnesota, Jennifer Thomsen Dec 2007

Analysis Of Hg And Stable Isotope Concentrations In Bald Eagle Feathers From The Great Lakes And Voyageurs National Park, Minnesota, Jennifer Thomsen

All Theses

Bald eagles (Haliaeetus leucocephalus) feed on a variety of aquatic and terrestrial wildlife. As top predators in their food chain, they may accumulate harmful concentrations of pollutants such as mercury, which can have detrimental effects on populations of this species. The stable isotope composition of feathers provides useful information about the food resources assimilated by bald eagles. The connection between mercury, (Hg), concentration and stable isotope concentration ( 13C and 15N) of feathers were measured to better understand the potential sources and pathways of Hg uptake by bald eagles living in the Great Lakes region of Michigan and Voyageurs National …


Network-Constrained Regularization And Variable Selection For Analysis Of Genomic Data, Caiyan Li, Hongzhe Li Dec 2007

Network-Constrained Regularization And Variable Selection For Analysis Of Genomic Data, Caiyan Li, Hongzhe Li

UPenn Biostatistics Working Papers

Graphs or networks are common ways of depicting information. In biology in particular, many different biological processes are represented by graphs, such as regulatory networks or metabolic pathways. This kind of {\it a priori} information gathered over many years of biomedical research is a useful supplement to the standard numerical genomic data such as microarray gene expression data. How to incorporate information encoded by the known biological networks or graphs into analysis of numerical data raises interesting statistical challenges. In this paper, we introduce a network-constrained regularization procedure for linear regression analysis in order to incorporate the information from these …


Comparison Of Compost Tea And Biological Fungicides For Control Of Early Blight In Organic Heirloom Tomato Production, Richard Kouyoumjian Dec 2007

Comparison Of Compost Tea And Biological Fungicides For Control Of Early Blight In Organic Heirloom Tomato Production, Richard Kouyoumjian

All Theses

The efficacy of compost tea was evaluated and compared alone and in combination with two biofungicides Serenade Max and Sonata for control of early blight caused by the fungal pathogen Alternaria tomatophila on tomato Solanum lycopersicum (L), heirloom cultivar `Cherokee Purple'. Results of field experiments over two growing seasons indicated that compost tea provided a low level of protection against early blight. The results were variable; most likely due to dry conditions and the presence of bacterial wilt the first year and tomato spotted wilt virus the second year. In both 2006 and 2007 field trials compost tea was not …


Provisioning And Prey Quality In Brown Pelicans (Pelecanus Occidentalis) In Charleston Harbor, South Carolina, Elena Sachs Dec 2007

Provisioning And Prey Quality In Brown Pelicans (Pelecanus Occidentalis) In Charleston Harbor, South Carolina, Elena Sachs

All Theses

I examined parent and nestling behavior during early chick rearing in Brown Pelicans (Pelecanus occidentalis) nesting at a colony in Charleston Harbor, South Carolina during the 2006 breeding season. There were significant differences in the frequency of feeding, attendance, and chick aggression according to chick age, although the pattern differed among behaviors. The rate of adult feeding, chick feeding and adult attendance all decreased with chick age while chick aggressive behavior peaked when chicks were ca. 21 d post-hatch. I found that nests with at least one juvenile parent had a lower average clutch size, hatch rate, and number of …


Effects Of Season Of Fire On Red-Cockaded Woodpecker (Picoides Borealis) Reproduction And The Breeding Bird Community Of A Longleaf Pine Ecosystem, Sarah Lauerman Dec 2007

Effects Of Season Of Fire On Red-Cockaded Woodpecker (Picoides Borealis) Reproduction And The Breeding Bird Community Of A Longleaf Pine Ecosystem, Sarah Lauerman

All Theses

Fire is the most important management tool in restoring and maintaining the longleaf pine ecosystem but the effects of season of burning on fauna are not fully understood. Of particular concern is the community of birds which breed in the longleaf pine forest, several of which are endangered, threatened or species of concern. This study examined the effects of season of fire on the breeding bird community and a population of red-cockaded woodpeckers (RCW) at Brosnan Forest in Dorchester, South Carolina. Fifty-eight RCW territories received dormant or growing season fire over a five-year period from 2001 to 2005. Prior to …


Phylogeny And Classification Of Hydropsychidae Subfamilies And Genera Of The World (Insecta: Trichoptera), Christy Geraci Dec 2007

Phylogeny And Classification Of Hydropsychidae Subfamilies And Genera Of The World (Insecta: Trichoptera), Christy Geraci

All Dissertations

The family Hydropsychidae is nearly ubiquitous in streams and rivers, with over 1600 described species worldwide. Hydropsychidae is ecologically important and its larvae play key roles as indicators of water quality. Conflicting morphological characters have obscured the evolutionary history of the subfamilies, and the wide diversity of phallic morphology among Hydropsyche sensu lato species has created unstable classification systems that have been disputed among authors. My research used five nuclear ribosomal and mitochondrial COI fragments to infer a molecular phylogeny for Hydropsychidae subfamilies and genera, focusing particularly on the Hydropsychinae and the Hydropsyche sensu lato lineage. The monophyly of four …


Household Food Security, Dietary Intake, And Anthropometric Assessment Of Dominican Children, Elizabeth Wall Dec 2007

Household Food Security, Dietary Intake, And Anthropometric Assessment Of Dominican Children, Elizabeth Wall

All Dissertations

The purpose of this study was to assess nutrition and food security status of Dominican school children and their families. Anthropometric measures, diet recalls, and household food security surveys were used as tools in this assessment. This assessment may assist in prioritizing programs for the transitioning country of the Commonwealth of Dominica.
In year 1, 199 children and 197 children in year 2 from 10 primary schools in 3 regions participated in the study. Four of the schools were involved with school feeding programs while six were not involved in school feeding programs. Weight was measured on an electric scale; …


Fungal Conversion And Supercritical Carbon Dioxide Processing For Value-Added Canola Oil, Meidui Dong Dec 2007

Fungal Conversion And Supercritical Carbon Dioxide Processing For Value-Added Canola Oil, Meidui Dong

All Dissertations

There is a growing awareness of health benefits of polyunsaturated fatty acids (PUFAs) e.g. arachidonic acid (ARA, C20:4n6) and eicosapentaenoic acid (EPA, C20:5n3). In general, plant seed oil and animal fat do not contains long-chain PUFAs with more than eighteen carbons. This study investigated the feasibility for addition of ARA and EPA to canola oil through the fermentation of fungi, Mortierella alpina, using canola flake, cake or meal as substrates. Supercritical CO2 extraction was also investigated for lipid extraction. In addition, a supercritical CO2 explosion process was characterized and applied to enhance oil extraction using supercritical CO2 and to potentially …


The Molecular Characterization Of The Virus And Virus-Like Agents Present In Ta Tao 5 Germplasm Of Prunus Persica , Diana Marini Dec 2007

The Molecular Characterization Of The Virus And Virus-Like Agents Present In Ta Tao 5 Germplasm Of Prunus Persica , Diana Marini

All Dissertations

Peach production in the southeastern United States is limited by late spring freezes. Ta Tao 5 germplasm, used either as an interstem or by chip bud inoculation, has been shown to delay bloom and avoid the effects of these late freezes. The growth modification is graft transmissible and the germplasm has been found to be infected with ACLSV, APruV-3, and PLMVd. Using a combination of PCR, cloning, and sequencing techniques, a molecular characterization of the three graft-transmissible agents present in Ta Tao 5 has been completed.

The complete nucleotide sequence of the genome of the isolate of ACLSV (ACLSV-Ta Tao …


Enhancing The Ability Of Panicum Virgatum To Survive Flooding And Its Effects On Soil Activity When Used For Lakeshore Stabilization, Lee Edwards Dec 2007

Enhancing The Ability Of Panicum Virgatum To Survive Flooding And Its Effects On Soil Activity When Used For Lakeshore Stabilization, Lee Edwards

All Dissertations

Reservoirs in upstate South Carolina are subject to erosion and vegetation has been placed to help stabilize banks, but soils are nutrient-poor and have high bulk densities. Panicum virgatum L. (switchgrass) has been planted in several sites, and it is hypothesized that over time, changes in microbial activity and soil quality will occur in response to the planting. As vegetated sites aged, acid phosphomonoesterase, nitrate reductase, and dehydrogenase activity increased. Low values of nitrogen fixation and substrate-induced respiration were measured at all sites with no statistical differences between sites. Fatty acids indicative of Gram negative bacteria were found in vegetated …


Development Of Novel Prolactin And Growth Hormone Receptor Agonists And Antagonists, John Langenheim Dec 2007

Development Of Novel Prolactin And Growth Hormone Receptor Agonists And Antagonists, John Langenheim

All Dissertations

Potential indications for human prolactin (hPRL) and human growth hormone (hGH) are the support and sustainment of lactation and the enhancement or reconstitution of the immune system when under dysregulation. A prolactin receptor (PRLR) antagonist, hPRL-G129R (G129R), and a PRLR and growth hormone receptor (GHR) antagonist, hGH-G120R (G120R), have been developed which may be useful for the treatment of breast cancer since PRLR is elevated in a majority of human breast tumors and makes cancer cells highly sensitive to the mitogenic and anti-apoptotic activity of hPRL and hGH.

As a single agent, G129R is more cytostatic than cytotoxic to human …


Nesting And Foraging Characteristics Of The Black Carpenter Ant Camponotus Pennsylvanicus (Degeer) (Hymenoptera: Formicidae), Donald Oswalt Dec 2007

Nesting And Foraging Characteristics Of The Black Carpenter Ant Camponotus Pennsylvanicus (Degeer) (Hymenoptera: Formicidae), Donald Oswalt

All Dissertations

Potential nesting sites of Camponotus pennsylvanicus (DeGeer) were investigated in South Carolina to determine if nesting sites features could be characterized by habitat features for black carpenter ant nests. Environmental data from forested plots showed large-scale habitat features such as vegetation density and canopy cover were not useful as indicators for the presence or absence of nests. Small-scale individual nest characteristics such as diameter at breast height of trees, log length, tree defect type or tree species were better indicators of occupied nests. In my study, C. pennsylvanicus preferred mature hardwood (Quercus spp.) trees approximately 30 cm in diameter and …


The Lss Supernodulation Mutant In Medicago Truncatula: Genetics, Characterization And Mapping, Arijit Mukherjee Dec 2007

The Lss Supernodulation Mutant In Medicago Truncatula: Genetics, Characterization And Mapping, Arijit Mukherjee

All Dissertations

The symbiotic association between legumes and nitrogen fixing rhizobia culminates in the formation of root nodules. Legumes control the extent of root nodule formation through a regulatory mechanism in which nodulating roots induce a shoot response that signals back to the roots, inhibiting further nodule initiation. Disruption of genes involved in this regulatory process lead to super or hypernodulation. The lss (like sunn supernodulator) mutant of Medicago truncatula has been identified as a naturally occurring supernodulation mutation in the Jemalong cultivar. The phenotype of lss is practically indistinguishable from the phenotype of the previously isolated sunn mutant with respect to …


Studies In The Biochemistry And Cell Biology Of Trypanosoma Brucei Hexokinases, Jeremy Chambers Dec 2007

Studies In The Biochemistry And Cell Biology Of Trypanosoma Brucei Hexokinases, Jeremy Chambers

All Dissertations

Trypanosoma brucei expresses two hexokinases (TbHK1 and TbHK2) that are 98% identical at the amino acid level. We previously found that recombinant TbHK1 (rTbHK1) has hexokinase activity, while rTbHK2 did not, a finding attributed to differences in the C-termini of the proteins. We found that the C-terminal tails of TbHK contained a novel motif specific for eukaryotic hexokinases found within the final helix of an ATP-binding domain. By altering the residues in the C-terminal tail of TbHK1 to resemble the residues found in TbHK2, we found that D454, F462, M466, and N469 were essential to TbHK1 catalysis. Additionally, we found …