|
Hill Farm Research Station |
|
|
|
|
1999 IMPACT REPORTS
Title: Teat Dips: Major Management Tools to Prevent Mastitis and Lower Somatic Cell Count Situation/Problem: The rate of new intramammary infections is dependent upon the number of mastitis-causing bacteria growing at the teat end. Dipping of teats in a germicidal solution before and after milking is the most beneficial management tool for dairymen to reduce the number of bacteria on teats, and subsequently prevent these organisms from gaining access to the interior of the udder and causing mastitis. The cow is exposed to environmental organisms such as Streptococcus uberis and Escherichia coli during the intermilking period when she is exposed to mud, manure, and bedding materials. A product is needed to form a thin, impregnable, bactericidal film over the teat end immediately after machine removal, which will seal the teat orifice and provide prolonged antibacterial activity against these bacteria. Action: Laboratory and field experiments have been initiated to develop an antibacterial surgical shield used in human medicine into a product that could serve as a germicidal barrier for cows teats during lactation as well as during the dry period. Initially, various formulations of the product were evaluated in vitro for germicidal activity against common mastitis-causing bacteria. The most efficacious formulation was then tested on cows' teats to determine efficacy in killing bacteria on teat skin. A variety of dyes were added and the one providing most visibility was chosen to evaluate for persistence on teat skin. A formulation was also developed for nonlactating cows to be applied to teats at dry-off and approximately 1 week prior to calving to augment the beneficial effect of dry cow therapy and to provide protection during the immediate prepartum period when the udder is susceptible to infection. Impact: Mastitis is the most important dairy cattle disease because it drastically reduces milk production. It is estimated that this disease causes production losses approaching $12 million in the state of Louisiana alone. The level of mastitis in southeast US dairies, as reflected in somatic cell counts (SCC), is quite high compared with national figures, which indicate that 85% of dairies are producing milk with SCC<400,000/ml. In Louisiana, approximately 50% of dairies are producing milk with SCC>400,000/ml. At present, the legal SCC limit for shipping milk is 750,000/ml; however, regulatory agencies may reduce this limit to 400,000/ml by 2003. Teat dipping is the most useful tool for dairymen to control the devastating losses caused by mastitis, and improved products are needed to further reduce the infection level in Louisiana dairies. It is believed that the development of novel germicidal barrier products will provide further control against environmental pathogens and help dairymen lower SCC in order to comply with future milk quality standards. Funding Sources: Financial support provided by LAES; Small Business Innovative Research Grant; Biomedical Development Corporation, Independent Businessmen Association (IBA), WestfaliaSurge. Contacts: Stephen C. Nickerson, Professor. Hill Farm Research Station, 11959 Hwy 9, Homer, LA 71040. Phone: (318) 927-9654, Fax: (318) 927-4139, e-mail: snickerson@agcenter.lsu.edu William E. Owens, Professor. Hill Farm Research Station, 11959 Hwy 9, Homer, LA 71040. Phone: (318) 927-9654, Fax: (318) 927-4139, e-mail: wowens@agcenter.lsu.edu Richard L. Boddie, Research Associate. Hill Farm Research Station, 11959 Hwy 9, Homer, LA 71040. Phone: (318) 927-9654, Fax: (318) 927-4139, e-mail: rboddie@agcenter.lsu.edu Title: "The Role of Horn Flies in Heifer Mastitis" Situation/Problem: Dairy heifers have been shown to be at risk for contracting mastitis caused by a variety of microorganisms. The majority of these infections are caused by the staphylococci, and often include Staphylococcus aureus as a major mastitis pathogen. Recent research at the Hill Farm Research Station has shown a direct link between horn flies and Staphylococcus aureus mastitis in dairy heifers. The collection and bacterial examination of horn flies from heifers revealed that Staphylococcus species including S. aureus are present on flies, indicating that these flies have the potential to serve as vectors for infecting heifer mammary glands. As a result of these observations, a model was developed using the horn fly that demonstrated a clear link between flies and mastitis in heifers. Techniques to control flies and prevent heifers from contracting mastitis are needed. Action: After consultation with Lane Foil at the Entomology Department at LSU, research scientists W. E. Owens and S. C. Nickerson and research associate Corinne Ray at the Hill Farm Research Station Mastitis Laboratory devised experiments implicating the horn fly in the cause and transmission of S. aureus mastitis in dairy heifers. Subsequent field studies have determined that when horn fly numbers exceed 50-100 flies per animal. heifers are at risk for scab formation and new mastitis cases caused by Staphylococcus aureus. A recently completed study using a pour-on insecticide and ear tags, suppressed horn fly numbers to below 50 per animal and reduced new mastitis infections significantly. Impact: These studies strongly implicate the horn fly in the cause and transmission of S. aureus mastitis among young dairy heifers. Dairy heifers have previously been considered uninfected and at minimal risk of contracting mastitis. The discovery that these animals do contract mastitis is very important to dairy farmers in Louisiana and across the nation. Recent studies showing control of horn flies results in less Staphylococcus aureus mastitis provide dairy farmers with information to protect young heifers. Dairy heifers represent the future of any dairy, and infections in the mammary glands of these young animals can destroy developing mammary tissue resulting in irreversible damage. Heifers with mastitis often freshen with blind or nonfunctional quarters and their potential productivity is greatly reduced. In addition, beef heifers have also been shown to contract Staph. aureus mastitis and horn flies are strongly suspected as the cause of this problem also. Fly control should be a integral part of a complete beef and dairy heifer health program to insure maximum productivity and profitability. Funding Sources: Financial support provided by LAES and in kind funding from Merck. Contacts: William E. Owens, Professor. Hill Farm Research Station, 11959 Hwy 9, Homer, LA 71040. Phone: (318) 927-9654, Fax: (318) 927-4139, e-mail: wowens@agcenter.lsu.edu Stephen C. Nickerson, Professor. Hill Farm Research Station, 11959 Hwy 9, Homer, LA 71040. Phone: (318) 927-9654, Fax: (318) 927-4139, e-mail: snickerson@agcenter.lsu.edu Corinne Ray, Research Associate. Hill Farm Research Station, 11959 Hwy 9, Homer, LA 71040. Phone: (318) 927-9654, Fax: (318) 927-4139, eE-mail: cray@agcenter.lsu.edu Title: Use of Poultry Waste as a Fertilizer Source for Grazing of Stocker Calves Situation/Problem: Over 80 percent of calves produced in Louisiana are sold at weaning with a high percentage of these calves purchased by stocker producers who graze these animals through the growing or stockering phase in other sections of the country. Louisiana has the resources available to incorporate a stocker-grazing system into a beef cattle enterprise. These resources include the potential for greater production of forages due to a longer growing season, adequate rainfall, and soils that readily respond to fertilization. Unfortunately, there are some limitations that have hindered the development of stocker grazing enterprises in Louisiana. One of these include the relatively high fertilizer costs associated with this production system. Using broiler litter for pasture fertilization is expected to increase as broiler production increases in northern Louisiana. Broiler litter can usually be obtained for shipping costs alone, so there is a significant economic incentive for beef producers to utilize this material as an alternative to commercial fertilizer. Action: A forage-beef research project being conducted at the Hill Farm Research Station calls for the evaluation of fertilizer sources on performance of stocker calves grazing bermudagrass pastures. Equal amounts of nitrogen, phosphorus, and potassium were applied by broiler litter or commercial fertilizer over the growing season. Forage quality and quantity as well as calf growth performance were assessed. Broiler litter was applied at recommended rates so as to avoid any harmful effects to soil or water resources. Impact: Similar growth performance was observed for calves grazing pastures fertilized with either broiler litter or commercial fertilizer. Furthermore, fertilizer costs were reduced by 38% with the use of broiler litter compared to the use of commercial fertilizer. This resulted in a reduction of fertilizer costs of over $33 per acre with the use of broiler litter. These findings help producers identify alternative fertilizer sources that offer a greater potential for profitability with their beef cattle enterprise. Louisiana's beef industry generated over $250 million to the state's economy in 1998. Beef cattle producers depend on research findings to improve their product to remain competitive and to better serve the consumers with a safe, abundant supply of beef. Funding Sources: Financial support provided by LAES Contacts: Sid DeRouen, Associate Professor. Hill Farm Research Station, 11959
Hwy 9, Homer, LA 71040.
Jeff Gillespie, Assistant Professor. Department of Agricultural Economics and Agribusiness, 101 Agricultural Administration Bldg., Louisiana State University, Baton Rouge, LA 70803. Phone: (225) 388-3282, Fax: (225) 388-2716, email: jmgille@lsu.edu Jerry Ward, Assistant Professor; Southeast Research Station. P.O. Box 567, Franklinton, LA 70438. Phone: (504) 839-2322, Fax: (504) 839-3202, email: jward@agcenter.lsu.edu TITLE: Effects of Herbaceous Weed Competition on Loblolly Pine Plantation Growth SITUATION / PROBLEM: Research has shown that herbaceous weeds have a negative impact on early growth and development of loblolly pine plantations. The early diameter growth that is lost to herbaceous weeds significantly impacts long-term plantation development. As a plantation approaches harvest age this early diameter growth loss is expressed as reduced wood yields and lower value products. Timber income can be reduced significantly, which impacts the financial potential of loblolly pine plantations. ACTION: Research has shown that early growth losses can be mediated by properly timed herbicide applications. Herbicide prescriptions should be developed for each plantation and applied post planting from late February through mid April. IMPACT: Long-term research at the Hill Farm Research Station
has shown that herbaceous weed suppression enhanced growth and development
of a 20-year-old loblolly pine plantation planted at a 6 X 6 foot spacing
(1,200 Trees per Acre). A $90.00 per acre investment in herbaceous weed
suppression produced the following results:
FUNDING SOURCES: Financial support provided by LAES and industrial research grants. CONTACT: Terry R. Clason; Professor. Hill Farm Research Station, 11959 Highway 9, Homer, LA 71040. Phone (318)927-2578, Fax (318)927-9505, e-mail -tclason@agcenter.lsu.edu
TITLE: Forage Management in Loblolly Pine Plantations Benefits Sawtimber Growth and Cattle Production SITUATION / PROBLEM: Introducing non-native improved forage crops under a forest canopy creates a commercial land management system on marginally productive land. Timber and forage are managed as a single integrated system. The interactions among timber, forage, and cattle are managed intensively to simultaneously produce timber commodities, a high quality forage resource, and efficient livestock production. This intense management results in a land management system that produces high value timber products, while providing short-term cash flow from the cattle component. ACTION: At the Hill Farm Research Station, annual forage management practices included fertilization (N, P, and K at 100, 40 and 22 lbs per acre), broadleaf weed control, and winter cropping with subterranean clover. Mean daily dry matter yield for each forage crop exceeded the daily nutrient requirements for 1.2 growing yearlings per acre with an average weight gain for a 165 day grazing season of 196 lbs per yearling. Warm season dry matter yields differed among forage crops; Pensacola bahiagrass, common bermudagrass, and Coastal bermudagrass averaged 5,875, 7,015, and 7,345 lbs per acre, respectively. Timber-grown forage yields were 10% less than open-grown yields. Annual timber production on the forage crop treatments averaged 2.1 cords per acre, while untreated check treatment production was 1.4 cords per acre. Annual sawtimber production on the forage crop treatments exceeded the check treatment by 200 board feet per acre. IMPACT: Over a fourteen year period, annual forage production costs, which included establishment and management costs, was $146 per acre. Annual cattle income averaged $137 per acre, while timber value accrued at an rate of $210 per acre. In addition, fertilization increased the yield of high quality, high value finish grade and shop grade lumber by 13 and 40%, respectively. Establishing forage crops in commercial loblolly pine plantation enhanced land value and provided an annual rate of return that exceeded open pasture grazing and timber only options by 7% and 5%, respectively FUNDING SOURCES: Financial support provided by LAES, Natural Resource Conservation Service, and National Agroforestry Center. CONTACT: Terry R. Clason; Professor. Hill Farm Research Station, 11959 Highway 9, Homer, LA 71040. Phone (318)927-2578, Fax (318)927-9505, e-mail - tclason@agcenter.lsu.edu |
|
|
| [Return
to Top] [Hill
Farm Home] [Special
Topics] Last Update: Friday, February 07, 2003 02:10:34 PM |