Abstracts 2001

02-03-004 Beckett, Jonathon L.

Effects of Long-Acting Estrogen-base Growth Promotant on Growth and Performance and Carcass Characteristics in Holstein Steers.

The use of growth-promoting implants in the US is widespread, although optimization of compound type and onset of implant exposure has not been completely resolved.  In particular, although implants dramatically increase average daily gain (~10%) and feed efficiency (~15%), there is evidence that implants decrease quality grades (Prime, Choice, Select and Standard) and tenderness of the meat.  The preponderance of research has been conducted on traditional beef cattle genetics.  While the vast majority of the cattle fed in the US are of traditional beef cattle background, there is a large number of steers that enter feedlots as byproducts of the dairy industry.  Indeed, California places approximately 600,000 Holstein steers in feedlots annually.  Due to the profound differences in growth characteristics between dairy breeds and cattle of more traditional beef genetics, the Holstein steers are fed for a longer period of time and thus are subjected to repeated implant regimens.  The implementation of repeated, serial implants can result in losses in efficiency and growth as the animals are processed more frequently, and are subject to more injury due to the more frequent handling.  As more investigators report on the interaction between genetic influences and implant effects, there is growing concern that traditional implant regimens are not adequately tested in Holstein steers, particularly as they relate to season of placement.  The objective of the proposed research is to test the efficacy of a long-lasting, sustained release estrogen implant, singularly, and in combination with other growth promotants.  Specifically, the following responses will be measured: (1) effect on growth and efficiency characteristics, (2) influence on quality grade, yield grade, dressing percent and ribeye area, and (3) effect of season on implant regimen.  The working hypotheses of the proposed research are (1) A long-acting estrogen implant can be used in a growth promoting strategy (which limits the number of times the cattle must be handled), maintains the rapid growth and high efficiency of other implant regimens, yet minimizes the detrimental effects of implants on carcass quality.  (2) Different strategies are appropriate depending on the season of placement into the feedyard.
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02-03-009 Costello, Michael

Cultural Practices for Integrating Arthropod Pest Management with Improvements in Grape and Wine Quality.

Key issues for grape growers in California include environmentally sound pest management, sustainable soil management, irrigation efficiency, optimal vine fertility and improving wine quality.  There is a great deal of interest in using irrigation management (regulated deficit irrigation) to improve color, maturity and flavor components of wine.  In addition, cultural practices such as cover cropping and irrigation management can have a significant effect on leafhopper numbers by influencing vine vigor.  Recent work suggests that water stress at critical times during the season can increase leafhopper mortality.  Spider mites are among the most widespread and troublesome grape arthropod pests in California, and these pests will be at the forefront of grape IPM in the next few years because of the probable loss of the most commonly used miticde, propargite (Omite), due to FQPA restrictions.  There is a strong relationship between vine stress and outbreaks of spider mites which has been long recognized, and water stress seems to be the most common type of stress leading to spider mite outbreaks.  There is also a fair amount of evidence correlating sulfur use with increased spider mite density.  To date, these cultural, pest management and grape quality issues have largely been studied separately by scientists within a particular discipline.  Our project integrates these issues into a whole systems vineyard management program, so that a set of production practices can be used to achieve multiple objectives.  Our studies focus on two objectives: 1) Irrigation strategies for managing leafhoppers and improving wine quality and 2) Soil and sulfur management for spider mites.  We have found that deficit irrigation can be timed to increase leafhopper mortality and improve wine quality, and we propose the continuation of these studies.  We also propose studies to measure the potential types of stress involved in making vines susceptible to spider mite outbreaks, and will focus our efforts on soil factors and the use of sulfur.
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02-03-059 Costello, Michael

Identifying Environmental Variables that Influence the Severity of Pierce’s Disease and the Glassy-winged Sharpshooter.

Pierce’s Disease (PD) of grapevines in caused by a bacterium (Xylella fastidiosa or Xf), and is transmitted by leafhoppers commonly known as sharpshooters.  PD is usually fatal in grapes, and in California, has caused millions of dollars of damage in the past decade.  Sharpshooters are a highly specialized group of leafhoppers.  There are at least three native sharpshooters which will transmit PD to grapes, but during the 1990s, an exotic species, the glassy-winged sharpshooter (GWSS) has become established in virtually every Southern California county, and has been trapped in over a dozen central valley and north coast counties.  The broad host breadth and strong flying ability of the GWSS makes it a much more serious vector of PD than any of the native sharpshooters.  There are many factors which may be involved in the expression of PD, including grape variety, climate, adjacent vegetation, proximity to riparian habitats, soil chemistry, soil physical factors, soil biology and soil water status.  The general objective of this study is to identify the various factors involved in the expression of PD.  We propose to investigate and evaluate these factors by collecting data from several regions throughout the state to analyze how the incidence and severity of PD in grapevines in influenced by their interaction.  All data collected will be combined into a database that will be analyzed with canonical correspondence analysis, which will allow us to assess many dependent variables along with many independent variables simultaneously.  In addition, we will evaluate the relative effectiveness of four trapping methods for monitoring sharpshooters, which will enable more effective surveillance techniques for sharpshooters in and around vineyards.
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02-03-010 Dietterick, Brian

LIDAR Geomorphic Evaluation of Watershed and Channel Characteristics in the Little Creek Watershed, Swanton Pacific Ranch

Recent developments using LIDAR (LIght Detection And Ranging) technology has permitted high-resolution, three-dimensional mapping and the ability to evaluate landscape features, such as channel and watershed characteristics.  The ability of high-resolution laser altimetry to accurately identify and evaluate watershed and channel characteristics will be investigated.  Comparisons will be made between field-mapped inner gorge areas, streamside landslides, and channel characteristics with the same landscape features generated with digital terrain models derived from the laser altimetry.  The results of this study are expected to determine whether LIDAR technology can provide an accurate and cost-effective alternative to delineating watershed and channel characteristics that contribute to cumulative watershed effects analysis required under California Forest Practice Rules.  A model will be developed to identify areas susceptible to streamside landslides to help predict potential sediment sources for the cumulative effects analysis and to possibly warrant additional WLPZ (watercourse and lake protection zone) considerations.
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02-03-016 Hampson, Brian

Aqueous Ozone for Pathogen and Cross-contamination Prevention

The project goal is to increase the safety of fresh produce commodities by means of utilizing ozone as a germicide for wash reduction of surface-borne pathogen contaminants.  Dissolved ozone in wash water rapidly eliminates microorganisms entrained in the water, thus preventing cross-contamination.  Additionally, this application allows for enhanced water recyclability and the economic employment of other germicides in combination.  Experiments are designed to elucidate the relationship between dose (concentration of ozone in solution x time of exposure) and logarithmic reduction of bacterial pathogens, pathogen indicator organisms, and indigenous microflora.  Aqueous ozone will be applied directly to the exterior of the fruits or vegetables; used to treat produce wash water for prevention of cross-contamination; and, applied as a spray wash to various food-processing surfaces inoculated with Escherichia coli, generic coliforms, and mixed populations of indigenous bacteria and fungi.  Experiments will also be performed to demonstrate the removal of the above microorganisms from the wash water as it makes its way to drainage, or is disposed of at the end of processing.  These results will be transferred to the produce and agricultural industries, and will assist with the development of good manufacturing practices for the use of ozone.  The timeliness of this research cannot be ignored.  Ozone is currently under review by FDA for government GRAS affirmation.  Self-affirmation by an expert panel occurred in 1997, and as a result, many companies are using, or are willing to use ozone, however, guidelines, evidence of efficacy, and dissemination of findings through conferences, symposia, and workshops is sparse.
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02-03-017 Brown, J. Wyatt

Bulk Modified Atmosphere Packaging of Fresh Produce Commodities

The use of Modified Atmosphere Packaging (MAP) technology is advancing from infancy to its adolescent stages.  As the technology matures, new applications that make the technology adaptable and user-friendly will require validation.  One such novel application for MAP is the SLX container system produced by SLX International, a San Luis Obispo-based corporation.  The container is made of food-grade plastic with a hermetic seal able to contain a modified inner atmosphere.  The container is re-usable and is considered a “green technology”, as opposed to paperboard containers that are single use and disposable.  It is the intent of the investigators to use the SLX container for the optimization of shelf-life and shipping quality of California-grown perishable agricultural commodities.  Primarily, fruits and vegetables applicable to MAP transport will be studies.  Research parameters include, but are not limited to, respiration rate of the commodity, color, taste, odor, and microbial load of the commodity, as well as extension of quality factors over time and distance shipped.  Optimization of these parameters for various produce commodities will allow for extended market access of such shipped items.  As regional markets are saturated, growers, packers, and shipper must seek distant markets.  In addition, with the advent and expansion of the global marketplace, more and more people desire fresh, high-quality produce items, from California too, if they can get them.  The main objective of the proposed study is to investigate and define the criteria and parameters necessary for optimization of quality, thus allowing for extended shipment of California agricultural commodities.  This will allow for sale of fresh items all around the globe, especially to lucrative, previously inaccessible markets in Asia and Europe.
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02-03-022 Eisenberg, Barry

Reducing Nitrogen and Pesticide Run-off from Container-grown Nursery Stock by Optimizing Cultural Practices Using a Predictive Environmental Interaction Model

Run-off water contamination is a serious problem for container-grown nursery stock.  The problem is acute when rain follows a dry period.  Developing data from irrigation/run-off collection plots with the ability to deliver “rain” will enable the construction of a predictive computer model to take a proactive approach in minimizing run-off issues.  This data must be linked to leaf, soil, and air temperature, soil and leaf nutrient status, photosyntheticly active irradiation and transpiration to have a tool industry can use to optimize production while minimizing chemical run-off.  The project will also fill the need to develop an education/training tool to be used in courses and for the industry.
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02-03-023 Headrick, David

Citrus IPM: Secondary Pest Biology and Demography II

Secondary pests, such as the fork-tailed katydid, Scudderia furcata Brunner, have in the past been minor pests of citrus in California.  In the last few years, such species have increasingly become a problem in commercial citrus production due to restrictions on broad-spectrum insecticide usage, reducing pesticide pressures normally controlling such pests.  In areas that are incorporating the use of natural enemies for control of homopterous pests, such as California red scale, conventional treatments for katydids and other secondary pests have proven to be upsetting.  Control strategies are changing every year in response to secondary pests.  Without a solid biological database on secondary pests, sound management decisions cannot be made – only guess work and that has proven to be an expensive and less than adequate option.  The ecological studies are the foundation of future pest management programs in agriculture.  The only way to achieve effective pest control is to understand the biology, lifecycles, and reproductive potential of these secondary, and now more important, pest species.  The main objective of this proposal is to provide support for the continuation of field studies on katydid damage and validation of our research model s for their eventual incorporation into a management program.
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02-03-028 Jimenez-Flores, Rafael

Organic Acid Determination by Capillary Electrophoresis as Quality Parameter of Buttermilk

This work focuses on defining and understanding the correlation between metabolically important organic acids and sensory characteristics of buttermilk.  Biological and processing parameters influence these characteristics, and they will be studies from the point of view of organic acid changes in buttermilk and cream.  Using descriptive analysis and capillary electrophoretic measurements of different organic acids as indicators of biological or microbial degradation, we will examine the effects of processing and storage variables on buttermilk samples manufactured at Cal Poly SLO and those collected from industrial sources.  This information is necessary for improvement of quality control and to increase value of buttermilk.
The first step of the research will be to develop a lexicon describing the sensory attributes of buttermilk.  The lexicon will be developed by a panel of 10-15 judges at UCD as part of the matching project to this one.  We will then develop and assess instrumental measurements of the organic acids by capillary electrophoresis.  The technique developed in our laboratory has proven to be valuable in determining microbial contamination, and is sensitive to most organic acids at concentrations of 2 ppm.
The last step of the research will be to examine the relations among expert quality ratings (from members of the dairy industry), consumer hedonic ratings (from consumers of dairy products) and descriptive ratings by the trained panel on a subset of commercial and prototype samples.  This will allow us to understand which sensory attributes drive quality ratings by experts and freshness acceptability among consumers.
The finding of the research will be prepared for communication in the form of presentation at national food industry and dairy industry meetings, publication in peer-reviewed journals and publication of recommendations for buttermilk manufacturers in industry newsletters and other outreach publications.  These  findings will form part of our DPTC ongoing short courses to the dairy industry.

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02-03-032 Montecalvo, Joseph

Characterization and Food Product Applications of Acidified Tomato By-Products

In order for the California tomato processing industry to remain competitive in a global economy, significant improvement of in-plant efficiencies must be developed.  In-plant efficiencies should be targeted at a reduction in operational costs, such as that generated from waste stream discharge, and utilization of process by-product, as technically and regulatorily feasible.  During the processing of processed tomato products such as sauce, whole peeled and paste, tomatoes must have their skins removed in a complete and efficient manner.  Lye peeling using sodium hydroxide has been shown in plant trials to significantly facilitate the peeling operation in comparison to steam peeling, a less efficient method.
As a function of lye peeling, tomato skins are generated, ground and pureed into a sauce, then acidified with food grade hydrochloric acid to pH 4.2.  The acidified tomato by-product represents all of the skin and small amounts of residual flesh from the tomato.
This project will compare the efficiency of using potassium hydroxide as the alkali peel agent and to generate an acidified tomato by-product low in sodium which will have significant marketing advantage in creating low sodium tomato sauces for consumers who must restrict dietary intake of sodium.  Additionally, storage studies will be used to determine how long the acidified tomato by-product can be stored under both room temperature and elevated (100-105oF) storage to simulate a model warehouse condition.  As a function of product development objectives, acidified tomato by-product will be incorporated into tomato and pizza sauces as well as salsa and as a topping sauce for canned whole peeled tomatoes.  Formulations for all ingredients will be optimized by sensory evaluation.  The significance of this study would be to develop specific product applications for the acidified tomato by-product.
Results from this study will aid commercial tomato processors in establishing quality control data and regulatory approval by the FDA.

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02-3-035 Noland, Jaymie

Embryo Recovery Rates Using Fresh and Frozen-thawed Quarter Horse Semen

The use of embryo transfer in the Quarter Horse (QH) industry has gained momentum over the last decade.  Factors that effect embryo recovery rates include the day of embryo recovery, age of donor, number of ovulations, and quality of the sire’s semen.  Until the approval of the use of frozen semen as of January 1, 2001, fresh and cooled semen was used exclusively with the breed in embryo transfer programs.  Little information is known regarding the effect of cryopreservation of semen on the embryo recovery rates within the QH breed.  By approving the use of frozen semen, the American Quarter Horse Association has provided the opportunity for faster genetic improvement and corresponding financial rewards for the QH breeders in California, a substantial portion of the 11.4 billion dollar equine industry in the state.  The influence of a genetically superior sire can dramatically affect the industry by the judicious use of cryopreservation of semen.  As the industry weighs the advantages and disadvantages of the use of frozen semen, the shortage of useful data regarding its effect on fertility in embryo transfer programs has created a dilemma for breeders.  The objective of this research project is to provide this data comparing frozen-thawed semen to the standard fresh semen as it relates to embryo recovery rates.  This information will assist the industry in making sound decisions regarding the appropriate use of frozen semen in QH embryo transfer programs.
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02-3-006 Pedersen, Mary and Berner, Louise

Breastfeeding Duration and Other Infant Practices Among Mothers in San Luis Obispo County

The purpose of this project is to evaluate current infant feeding practices, particularly breastfeeding duration rates and reasons for discontinuation of breastfeeding, among new mothers in San Luis Obispo County in order to support development of strategies for breastfeeding promotion.  Moreover, the results will provide baseline information on which to evaluate success of future promotion programs.  Breast milk is widely regarded as the food of choice for the vast majority of infants, and it is recommended as the exclusive source of nourishment during the first six months of life.  While breastfeeding initiation rates are high in San Luis Obispo and California, there is no statewide or local information on breastfeeding duration for a cross-section of the population.  Data collected nationally and on subgroups of women, however, reveal that most women discontinue breastfeeding after several weeks or months – before the full economic and health benefits can be realized.  The US Department of Health Services, in its “Blueprint for Action on Breastfeeding”, has called on researchers to “conduct research that identifies the social, cultural, economic, and psychological factors that influence infant feeding behaviors” and to “monitor trends on the incidence and duration of exclusive, partial, and minimal breastfeeding, including minority and ethnic groups.”  The study proposed here would do so.  We plan to conduct a longitudinal survey (primarily by telephone) on infant feeding practices, with emphasis on breastfeeding duration and reasons for discontinuation, of a representative sample of new mothers in SLO County over a one-year period.  Selected mothers will be surveyed initially in the hospital (to ascertain willingness to participate, initiation of breastfeeding, and demographic characteristics).  Follow-up phone calls will be made at 1 month postpartum, and again at 3, 6, and 9 months.  Results will provide data on breastfeeding duration among mothers in SLO County and the primary factors associated with discontinuation or success of breastfeeding.  In the short term, results will provide important data in support of nutrition education efforts of the United States Department of Agriculture (especially the WIC program), County Cooperative Extension, and local public health groups.  In the longer term, this study can contribute to better health and financial savings for mothers and their children.
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02-3-041 Piirto, Doug

Silviculture Management Strategies for Pitch Canker Infected Ano Nuevo Stands of Monterey Pine – pt 2

Pitch Canker (Fusarium subglutinans) has become a major cause of growth loss, mortality, and associated economic impacts in California Monterey pine forests.  There remains a strong need for science based forest management guidelines of the Monterey pine forest in California given the high public interest and concern over the spread of pitch canker and the decline of the Monterey pine forest.  An opportunity exists to develop long-term Monterey pine forest management studies for pitch canker infected native stands at California Polytechnic State University’s forest property in Santa Cruz county call Swanton Pacific Ranch.
Funding was provided by the California Department of Forestry and Fire Protection to: 1) initiate long-term forest management studies in the native Monterey pine forests at Swanton Pacific; and 2) develop guidelines for regeneration and management of Monterey pine forests in California in the presence of pitch canker.  The research work is being done in collaboration with a number of institutions, organizations, research scientists, and graduate student.
An initial ARI grant was awarded to cover the first three of six proposed objectives: 1) install a Continuous Forest Inventory System for the Scotts Creek Study Area; 2) collect seed from Monterey pine pitch canker resistant trees; 3) plant this resistant seed in greenhouse nurseries; $0 outplant these resistant seedlings as part of the group selection experimental design; 5) evaluate the effectiveness of broadcast seeding; and 6) develop a model to visually characterize the influence of pitch canker on Monterey pine stands.
This project will address the last three objectives and will overlap the longer-term of the CDF funding.

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02-3-042 Pillsbury, Norm

Long-Term Growth, Sudden Oak Death Assessment and Economic Viability of Coast Live Oak in Three California Counties – Third Remeasurement/17 Years

This study, which began in 1984, is the only long-term sustainability study on oak woodlands in California.  Since little is known about economic sustainability, site productivity, regeneration, tree growth and the potential effects of harvesting on oak woodlands, this project continues to supply valuable information to ranchers, landowners and foresters who wish to maximize fiber production in existing stands or want to compare the potential for different management strategies.
In addition, the recent development of the devastating sudden oak death fungus has caused widespread concern regarding the survival of native oak woodlands in Central California.  The study has been expanded to provide an assessment of the occurrence of Sudden Oak Death and will provide baseline data on oak mortality.  It will also document the rate of the disease spread in the central coast of California.  Sudden Oak Death has been found in two of the three counties under study.

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 02-3-043 Plummer, William

Efficacy of Adding Platelet Activating Factor (PAF) to Extend Semen for AI to Enhance Conception Rates

Recent collaboration with Dr. John Diehl of Clemson University studied the levels of PAF in the gravid reproductive tracts of swine.  This new study is designed to correlate PAF activity (ligand and receptor) in sperm relative to fertility, circulating androgen levels, semen characteristics, and pregnancy outcomes (ie. Litter size).  In particular, pregnancy outcomes will be studied in both pigs and cattle under artificial insemination practices, with and without additional PAF.
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02-3-054 Vance, Robert

Development of a Low-fat, Cold Bound Restructured Lamp Chop Suitable for Broiling

Consumers of meat generally look for products that are lean, palatable and convenient to prepare.  Recent increases in US poultry, pork and beef consumption have been attributed to the development of new products that are better portioned, easy to prepare and have a unique taste characteristics.  Lamb consumption in the US, on the other hand, has been on the decline.  Reasons for this include perceived poor palatability, variability in portion size and difficulty of preparation.  Recognizing these problems, California sheep producers are interested in the development of lamb products that are low fat, consistent in size and eating quality, easy to prepare, and can be competitively priced.  Lamb shoulder is a low value commodity that can be used to produce such products.  Lamb shoulder meat, boned and trimmed of all external and seam fat, will be combined with seasoning and a commercial cold meat binding material to produce a restructured chop of uniform composition that can be portion sized and cooked quickly on a broiler or grill.  Finished product acceptability will be evaluated via consumer taste-testing.  Successful production could provide American consumers with a lamb alternative to other similarly produced meat products.
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02-3-056 Walter, Virginia

Continued Studies of the Effect of Retractable Roof Greenhouses on Solarization

This project will help determine the effect of seasonal solarization activities on weed population within retractable roof greenhouse structure growing fresh cut flower crops.  Current methods of soil disinfestations in field production involve the use of methyl bromide, a chemical being phased out for environmental concerns by 2005.  For fresh flower field producers to remain economically viable, alternative methods of soil disinfestations must be developed.  Soil borne problems such as weeks, nematodes and diseases can be controlled with the use of heat.  Generating it using solarization techniques has been demonstrated in inland climates such as the Central Valley of California, but the majority of fresh flowers are grown in cooler coastal climates of California.  Field flower growers are also building retractable roof greenhouses to aid in year round field production.  If the effect of solarization with such a structure can be demonstrated successfully on a seasonal basis, this will help growers remain economically viable in an environmentally friendly and legal way.
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02-3-060 Burt, Charles

Drip Irrigation Salinity

Drip irrigation is commonly mentioned as the best means for improving efficiencies and helping to solve California's water problems.  Specifically, the CALFED program has targeted the funding of new drip/micro systems as the single best option for generating true water conservation in California.  The CALFED program has particularly noted that SDI (subsurface drip irrigation) may yield significant decreases in non-beneficial evaporation losses.   Various programs by electric utilities and others will also provide future funding to stimulate an increase in the drip irrigated acreage in California.

However, there have been serious failures of drip systems due to salt accumulation around drip emitters - indicating serious potential problems in arid areas (such as the San Joaquin Valley) with the sustainability of some types of drip irrigation (particularly SDI).   There is almost no systematic diagnostic research of the problem in San Joaquin Valley conditions.  To this point in time, it has been largely assumed that there are no problems unless one irrigates with brackish water or is in a high water table area.  But there is no data to support such an assumption.  This research will examine "typical" drip systems, and some potentially hazardous ones (in Panoche Water District), to determine if there are indeed damaging accumulations of salt.   If there are, the study will identify any the special leaching requirements needed for salt removal around drip emitters, as well as identify the important management practices needed to create a sustainable irrigated environment with drip.

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02-01-007 Jimenez-Flores, Rafael

Genetic, Nutrition and Processing Factors Affecting the Lipid and Protein Composition of Buttermilk

The general objective is to evaluate protein and lipid composition of milk fat globule membrane (MFGM) present primarily in buttermilk, of cows with well-defined genetics and under different nutritional feeding strategies.  To this purpose, three areas and researchers are identified.
Dr. Medrano has been studying the importance of several genes involved in de-novo fatty acid synthesis of membrane lipids in cows.  He will continue to refine the genomic analysis, characterizing important candidate genes coding for genetic variants of milk proteins and enzymes such as stearoyl-CoA-desaturase, that impart specific properties to the mammary gland lipids and therefore to the MFGM in the selection of cows for this work.
Genetics and nutrition determine the composition of lipids in milk.  For this reason, Dr. DePeters has designed a suitable number of diets containing different components known to modify the composition of fat in milk of genetically selected cows.  The milks derived from this work will be used to establish changes in lipid and protein composition of the MFGM.
We at DPTC will use advanced analytical techniques, as well as pilot plant procedures that have full acceptability in the dairy industry to analyze and process these cream samples, and the resulting buttermilk.  In addition, DPTC is sought as a supplier to the scientific community of valuable fractions of this commodity.  Thus, a good understanding of the relationship between composition and variables or biological parameters is vital to be able to become a premier supplier.

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