Progress 04/15/14 to 01/28/21
Outputs
Target Audience:The target audience was U.S. dairy producers, veterinarians and animal scientists. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?We had four PhD and two masters graduate students complete work on this BLV project. One more PhD student and two more masters student are still working to complete their degrees. Three assistant professors joined our BLV research group. We collaborated with Japanese BLV researchers to improve the interpretation of our results, and worked with three private firms developing BLV diagnostic technology. One of us is the editor of a special issue journal regarding BLV. How have the results been disseminated to communities of interest?This last year focused on publication of our results in peer-reviewed journals. Our website (WWW.BLVUSA.com) will be continually expanded and improved in the years ahead as our results are published. We continued work with our Extension service and our industry partners at NorthStar Laboratories Cooperative andAdvanced Animal Diagnostics to offer a BLV testing Extension program. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
The database produced from our national survey of dairy farms was used to verify the decreased survival of BLV-infectedcattle and the dose-response between herd milk production and herd prevalence of BLV ELISA antibodies. Several field trialswere published regarding controlling BLV in dairy herds. One field trial continues in which BLV transmission is being reducedby segregating or removing those cows with the highest proviral load (super-shedders). Objective 1: The results were published of our national survey of 4,120 dairy cows from 103 commercial dairy herds in 11states. Each 10% increase in prevalence was associated with a 430.7 lb (195.8 kg) loss in rolling herd average milkproduction, which is a greater loss than what was found in our 2010 study of Michigan herds. A survival analysis found thatELISA-positive cows were 30% more likely that their BLV-negative herdsmates to die or be culled during the subsequent 32months. Objective 2 and 3 - BLV Intervention Field Trials: Three herds with a BLV prevalence of under 5% attempted toeradicate BLV by culling all ELISA-positive cattle from their milking herds. Two herds achieved a totally negative milking herdbut were eventually re-infected by incoming heifers. Culling of all ELISA-positive cattle was the method used to achieveeradication in over 20 other nations, and it would appear to be as effective in the U.S. except young stock must also be free ofBLV to prevent re-introduction of the disease. An intervention field trial in three herds followed ELISA-negative cattle which had been randomly assigned to receive eitherno special treatment (negative controls) or to always receive a new hypodermic needle and new reproductive examinationsleeve. The control group experienced a rate of new infection of 16.4% (40/240) and the intervention group had aninsignificantly higher rate of 20.2% (53/262). A second intervention field trial on three small dairy herds attempted to control BLV transmission by segregating or cullingthose cattle with the highest blood lymphocyte count and proviral load. The theory behind this intervention was that cows withhigh lymphocyte counts and high proviral load are responsible for most transmission to their BLV-susceptible herdmates.Over the course of 3 years, the ELISA prevalence went from about 65% of the milking cows infected to 20% infected. Fourmore herds were recently added to this field trial which is ongoing. A third intervention study is continuing on a 3,000-cow herd using lymphocyte count, BLV ELISA and BLV proviral load toprioritize cattle for segregation and culling. This farm has reduced the percentage of cows with a lymphocyte count over10,000/μL of blood from 4.22% to 1.04%. Cattle with lameness were found to have significantly higher blood lymphocytecounts and BLV proviral load. One of the major BLV research questions regards the genetic determinants for developing high proviral load. GenomicDNA samples from ~400 ELISA-positive cows are being analyzed with BoLA and microRNA sequencing. We are conductingBLV transcriptional profiling to profile animals which have remained BLV-negative, those with low-PVL, those with high-PVLand animals which have advanced BLV disease. We isolated RNA for preparation of both microRNA and messenger RNAlibraries for sequencing. These samples have been submitted for analysis and are results expected to be delivered nextmonth. Surveys were completed of beef cattle and white-tailed deer in order to evaluate the impact of reservoirs of infection on anypossible regional or national BLV eradication efforts. Michigan white-tailed deer (n=143) showed no ELISA evidence of BLVinfection, however PCR results are pending. BLV ELISA prevalence in beef bulls was 45% (54/120) and BLV ELISAantibodies were found in 48% (19/39) of the cow-calf farms that presented beef bulls for breeding soundness exams. Wefound that 77.7% (21/27) of beef cow-calf herds had at least one ELISA-positive animal and 29.3% (930/3,175) of the testedbeef cows were ELISA-positive. We concluded that there was no evidence that any attempted dairy BLV eradication effortmight be hindered by a wild deer reservoir, but the beef cattle population maintains a substantial source of BLV infection. Our laboratory studies demonstrate that BLV infection in dairy cattle has a much greater effect on the host beyond the well-recognized lymphoma development that occurs in <5% of infected cattle. Overall impairment of antibody production andinterference with T cell immunity was observed along with decreased total IgA concentrations in milk and saliva of BLVELISA-positive cows. This immune disruption likely contributes to the observed increased risk in infected cattle of the rates ofsome diseases, decreased milk production and increased culling. The database from our various projects has provided us an opportunity to compare the results of 3 diagnostic tests for BLV:1) the serum or milk ELISA test for gp51 BLV antibodies (our best measure of previous exposure), 2) the lymphocyte count(our best indication of immune disruption) and 3) the qPCR proviral load (probably our best estimate of the infectivity of theblood and other body fluids). Two of our field trials required semi-annual testing of our Michigan study herds. This ELISA testing was done as close aspossible to November 1st and May 1st of each year, enabling us to compare rates of new BLV infections between thesummer biting-fly season and the winter months when Michigan has no biting flies. No significant seasonal differences were observed. All previous studies of the impact of management factors on BLV occurrence used prevalence and their dependent variablerather than incidence. In contrast, we sought to identify management practices as determinants of the incidence rate of newBLV infections in Michigan dairy herds. Milk samples were collected from cohorts of approximately 40 cows on 112 Michigandairy herds and tested for BLV using an antibody capture ELISA. Cows were subsequently followed for an average of 21months. Cows negative for anti-BLV antibodies and still present in their respective herds were retested by ELISA for BLV toestimate on-farm incidence rates (rate of new infection). The overall incidence rate among all cows retested was 1.46infections per 100 cow-months at risk. Objective 4 - Education: The results from our previous studies were analyzed to estimate the cost of BLV on one of ourfield study herds. The analysis is shown on our BLVUSA website http://blv.msu.edu/impact/index.html. Reduction in milkproduction and cow longevity were the greatest loss components. The total annual cost was estimated at $38,000 for each100 milking cows. This economic analysis will be the basis of future educational and training scenarios. Our website atwww.BLVUSA.com is now being updated based on recent developments in BLV research. Objective 5 - Extension: No new Extension projects were initiated this past year.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Bartlett PC, Ruggiero VJ, Hutchinson HC, Droscha CJ, Norby B, Sporer KRB, Taxis TM. Current Developments in the Epidemiology and Control of Enzootic Bovine Leukosis as Caused by Bovine Leukemia Virus. Pathogens. 2020 Dec 18;9(12):1058.
|
Progress 04/15/19 to 04/14/20
Outputs
Target Audience:U.S. Dairy producers, veterinarians and animal scientists Changes/Problems:We were granted a no-cost extension due to being locked out of our labs durinug the COVID-19 pandemic. With the exception of the one continuing field trial, this last year will be focused on publishing our results. What opportunities for training and professional development has the project provided?We have had four PhD and two masters graduate students complete work on this BLV project. One more PhD student and two more masters student are still working to complete their degrees. Three assistant professors have joined our BLV research group. We are collaborating with Japanese BLV researchers to improve the interpretation of our results, and are also working with three private firms developing BLV diagnostic technology. One of us is the editor of a special issue journal regarding BLV. How have the results been disseminated to communities of interest? This last year has focused on publication of our results in peer-reviewed journals. Our website (WWW.BLVUSA.com) will be continually expanded and improved in the years ahead as our results are published. We continued work with our Extension service and our industry partners at NorthStar Laboratories Cooperative and Advanced Animal Diagnostics to offer a BLV testing Extension program. What do you plan to do during the next reporting period to accomplish the goals? Several more publications are planned reporting on the results of previous years. We will continue the one remaining intervention field trial to while funds remain.
Impacts
What was accomplished under these goals?
The database produced from our national survey of dairy farms was used to verify the decreased survival of BLV-infected cattle and the dose-response between herd milk production and herd prevalence of BLV ELISA antibodies. Several field trials were published regarding controlling BLV in dairy herds. One field trial continues in which BLV transmission is being reduced by segregating or removing those cows with the highest proviral load (super-shedders). Objective 1: The results were published of our national survey of 4,120 dairy cows from 103 commercial dairy herds in 11 states. Each 10% increase in prevalence was associated with a 430.7 lb (195.8 kg) loss in rolling herd average milk production, which is a greater loss than what was found in our 2010 study of Michigan herds. A survival analysis found that ELISA-positive cows were 30% more likely that their BLV-negative herdsmates to die or be culled during the subsequent 32 months. Objective 2 and 3 -BLV Intervention Field Trials:Three herds with a BLV prevalence of under 5% attempted to eradicate BLV by culling all ELISA-positive cattle from their milking herds. Two herds achieved a totally negative milking herd but were eventually re-infected by incoming heifers. Culling of all ELISA-positive cattle was the method used to achieve eradication in over 20 other nations, and it would appear to be as effective in the U.S. except young stock must also be free of BLV to prevent re-introduction of the disease. An intervention field trial in three herds followed ELISA-negative cattle which had been randomly assigned to receive either no special treatment (negative controls) or to always receive a new hypodermic needle and new reproductive examination sleeve. The control group experienced a rate of new infection of 16.4% (40/240) and the intervention group had an insignificantly higher rate of 20.2% (53/262). A second intervention field trial on three small dairy herds attempted to control BLV transmission by segregating or culling those cattle with the highest blood lymphocyte count and proviral load. The theory behind this intervention was that cows with high lymphocyte counts and high proviral load are responsible for most transmission to their BLV-susceptible herdmates. Over the course of 3 years, the ELISA prevalence went from about 65% of the milking cows infected to 20% infected. Four more herds were recently added to this field trial which is ongoing. A third intervention study is continuing on a 3,000-cow herd using lymphocyte count, BLV ELISA and BLV proviral load to prioritize cattle for segregation and culling. This farm has reduced the percentage of cows with a lymphocyte count over 10,000/µL of blood from 4.22% to 1.04%. Cattle with lameness were found to have significantly higher blood lymphocyte counts and BLV proviral load. One of the major BLV research questions regards the genetic determinants for developing high proviral load. Genomic DNA samples from ~400 ELISA-positive cows are being analyzed with BoLA and microRNA sequencing. We are conducting BLV transcriptional profiling to profile animals which have remained BLV-negative, those with low-PVL, those with high-PVL and animals which have advanced BLV disease. Weisolated RNA for preparation of both microRNA and messenger RNA libraries for sequencing. These samples have been submitted for analysis and are results expected to be delivered next month. Surveys were completed of beef cattle and white-tailed deer in order to evaluate the impact of reservoirs of infection on any possible regional or national BLV eradication efforts. Michigan white-tailed deer (n=143) showed no ELISA evidence of BLV infection, however PCR results are pending. BLV ELISA prevalence in beef bulls was 45% (54/120) and BLV ELISA antibodies were found in 48% (19/39) of the cow-calf farms that presented beef bulls for breeding soundness exams. We found that 77.7% (21/27) of beef cow-calf herds had at least one ELISA-positive animal and 29.3% (930/3,175) of the tested beef cows were ELISA-positive. We concluded that there was no evidence that any attempted dairy BLV eradication effort might be hindered by a wild deer reservoir, but the beef cattle population maintains a substantial source of BLV infection. Our laboratory studies demonstrate that BLV infection in dairy cattle has a much greater effect on the host beyond the well-recognized lymphoma development that occurs in <5% of infected cattle. Overall impairment of antibody production and interference with T cell immunity was observed along with decreased total IgA concentrations in milk and saliva of BLV ELISA-positive cows. This immune disruption likely contributes to the observed increased risk in infected cattle of the rates of some diseases, decreased milk production and increased culling. The database from our various projects has provided us an opportunity to compare the results of 3 diagnostic tests for BLV: 1) the serum or milk ELISA test for gp51 BLV antibodies (our best measure of previous exposure), 2) the lymphocyte count (our best indication of immune disruption) and 3) the qPCR proviral load (probably our best estimate of the infectivity of the blood and other body fluids). Two of our field trials required semi-annual testing of our Michigan study herds. This ELISA testing was done as close as possible to November 1st and May 1st of each year, enabling us to compare rates of new BLV infections between the summer biting-fly season and the winter months when Michigan has no biting flies. No significant seasonal differences were observed. All previous studies of the impact of management factors on BLV occurrence used prevalence and their dependent variable rather than incidence. In contrast, we sought to identify management practices as determinants of the incidence rate of new BLV infections in Michigan dairy herds. Milk samples were collected from cohorts of approximately 40 cows on 112 Michigan dairy herds and tested for BLV using an antibody capture ELISA. Cows were subsequently followed for an average of 21 months. Cows negative for anti-BLV antibodies and still present in their respective herds were retested by ELISA for BLV to estimate on-farm incidence rates (rate of new infection). The overall incidence rate among all cows retested was 1.46 infections per 100 cow-months at risk. Objective 4 -Education:The results from our previous studies were analyzed to estimate the cost of BLV on one of our field study herds. The analysis is shown on our BLVUSA website http://blv.msu.edu/impact/index.html. Reduction in milk production and cow longevity were the greatest loss components. The total annual cost was estimated at $38,000 for each 100 milking cows. This economic analysis will be the basis of future educational and training scenarios. Our website at www.BLVUSA.com is now being updated based on recent developments in BLV research. Objective 5 - Extension: No new Extension projects were initiated this past year.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Benitez, Oscar J. Bob Norby, Paul C. Bartlett, Daniel L. Grooms, Effect of Bovine Leukosis Virus on Beef Cow Longevity. 99th Annual Conference of Research Workers in Animal Diseases (CRWAD), Chicago, Illinois, US, 2018.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Benitez, Oscar J. Bob Norby, Paul C. Bartlett, Daniel L. Grooms. The role of breeding bulls in Bovine Leukemia Virus transmission. Phi Zeta Research day, College of Veterinary Medicine. MSU, 2018.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Benitez, Oscar J. Jennifer Roberts, Bob Norby, Paul C. Bartlett, Daniel L. Grooms, Bulls as a Source of Bovine Leukemia Virus During Natural Breeding. 51th Annual Conference of the American Association of Bovine Practitioners, Phoenix, Arizona, US, 2018.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Coussens P.M., M.C. Frie, M.E. Cooke, B.W. Kirkpatrick Bovine leukemia virus alters the status of T cells in PBMCs from infected cattle Conference of Research Workers in Animal Diseases (Oral Presentation) 2018.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
DeJong T N, Swenson C L, Taxis T M, Norby B, Droscha C, Bartlett P C (2019) Enhancing a Sustainable Dairy Industry by Controlling Bovine Leukemia Virus. Abstract/Oral Presentation 116. CRWAD 2019 Conference, Chicago Marriott, Chicago, Illinois, November 2019.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
DeJong T N, Swenson C L, Taxis T M, Norby B, Droscha C, Bartlett P C (2019) Enhancing a Sustainable Dairy Industry by Controlling Bovine Leukemia Virus. Abstract/Oral Presentation. All Things BLV 2019 Conference, Michigan State University, East Lansing, Michigan, October 2019.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
DeJong T N, Swenson C L, Taxis T M, Norby B, Droscha C, Bartlett P C (2019) Enhancing a Sustainable Dairy Industry by Controlling Bovine Leukemia Virus. Abstract/Oral Presentation. Animal Science Graduate Research Forum, Michigan State University, East Lansing, Michigan, October 2019.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Dziuba, M., Greenlick, A., Ruggiero, V., Bartlett, P. C., Wilson, C., Coussens, P. M. Effects of bovine leukemia virus on antibody levels in milk, serum, and saliva. Conference of Research Workers in Animal Diseases, [Oral Presentation] 2018
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Hutchinson, H., Ruggiero, V. J., Norby, B., Sporer, K. R. B., Bartlett, P. C. Interrelated measures of bovine leukemia virus disease infection and disease progression. Conference of Research Workers in Animal Diseases, 2019. [Oral Presentation]
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Hutchinson, H, Ruggerio, V.J., Norby, B., Sporer, K.R.B., Bartlett, P.C. 2019. Interrelated measures of Bovine Leukemia Virus disease infection and progression. Conference for Research Workers in Animal Diseases. November 2019.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Hutchinson, H., Swenson, C.L., Taxis, T.M., Norby, B., Bartlett, P.C. 2019. Evaluation of an on-site blood leukocyte test for use in cattle. Conference for Research Workers in Animal Diseases. November 2019.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Hutchinson, H, Ruggerio, V.J., Norby, B., Bartlett, P.C. 2019 Longitudinal Analysis of Diagnostic Measures of Bovine Leukemia Virus Infections Michigan State University 29th Annual Phi Zeta Research Day. October 3, 2019
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Hutchinson, H. C., Norby, B., Droscha, C., Kellogg, C., Bartlett, P.C. 2018. Proviral, antibody, and lymphocyte dynamics in steers following intramuscular challenge with bovine leukemia virus. Conference for Research Workers in Animal Diseases. December 2, 2018.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Kellogg. C., B. Norby, C. Droscha, L. Sordillo. Impact of bovine leukemia virus on leukocyte counts and ELISA status through dry-off & parturition in dairy cattle. Conference of Research Workers in Animal Diseases, 2018. (Poster)
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2020
Citation:
Kesler, K., Dejong K.K. , T. Sporer, K., Droscha, C., Taxis, T. Profiling host Transcriptome During Bovine Leukemia Viral Pathogenesis. Plant and Animal Genome Conference (PAG). San Diego, California January 10-15th, 2020. Oral Presentation.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Kesler, K., LaDronka, R., Norby, B., Bartlett, P., Bovine Leukemia Virus in US Dairy Cattle: Descriptive Epidemiology from a National Survey. American Association of Bovine Practitioners Annual Meeting. Louisville, KY. September 12-14th, 2019. Oral Presentation
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Norby, B., P. Bartlett, P. Coussens, R. Erskine, C. Kellogg, L. Sordillo. Impact of Bovine Leukemia Virus Infection on Disease Incidence and Severity in Dairy Cattle. Conference of Research Workers in Animal Diseases, 2018. (Poster)
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
LaDronka R.M., S. Ainsworth, M.J. Wilkins, B. Norby, T.M. Byrem, P.C. Bartlett.Bovine leukemia virus in U.S. dairy cattle: update on descriptive epidemiology from a national survey Conference of Research Workers in Animal Diseases, Chicago, IL 2108. (Presentation)
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Lohr, C., Sporer, K. R. B., Ruggiero, V. J., Droscha, C. J., Bartlett, P. C. Sequence-based typing of MHC BoLA alleles to determine BLV host resistance. Conference of Research Workers in Animal Diseases, [Poster] 2019.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Lohr, Chaelynne E. Vickie Ruggiero, Casey J. Droscha, and Paul C. Bartlett. NGS genotyping of MHC Class II loci to determine BLV host resistance in commercial dairy herds. Plant and Animal Genome Conference XXVIII (PAG). San Diego, CA. January 10-15, 2020. Poster Presentation.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Ruggiero, V. J., Norby, B., Erskine, R., Sporer, K. R., Droscha, C. J., Bartlett, P. C. Evaluating control of bovine leukemia virus in dairy herds. Conference of Research Workers in Animal Diseases, 2018.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Sporer, K. R. B., Droscha, C. J., Ruggiero, V. J., Byrem, T. M., Bartlett, P. C. Development of a novel assay for identifying highly infectious cows with bovine leukosis. Conference of Research Workers in Animal Diseases, [Oral Presentation] 2018
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Sporer Kelly R.B., Casey J. Droscha, Todd M. Byrem, and Paul C. Bartlett. BLV Super-shedders: Insights into a longitudinal field trial. 100th Annual Conference of Research Workers in Animal Diseases (CRWAD). Chicago, IL. November 3-5, 2019. Oral Presentation.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Sporer, Kelly R.B., Casey J. Droscha, Todd M. Byrem, and Paul C. Bartlett. BLV Super-shedders: Insights into a longitudinal field trial. Annual BLV Meeting. Michigan State University, East Lansing, MI. October 24, 2019. Oral Presentation.
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2019
Citation:
Ruggiero, vickie j. Field studies on the control of bovine leukemia virus in dairy cows. Dissertation. Michigan State University, 2019
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Ruggiero, V. J., Bartlett, P. C. Control of bovine leukemia virus in three U.S. dairy herds by culling ELISA-positive cows. Veterinary Medicine International, 2019; vol. 2019, Article ID 3202184. doi: 10.1155/2019/3202184.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Benitez, Oscar J., Roberts, Jennifer., Norby, Bob., Bartlett, Paul C., Grooms, Daniel L. " Lack of Bovine leukemia virus transmission during natural breeding of cattle." Theriogenology, 126 (2019): 187-190.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Benitez, Oscar J., Roberts, Jennifer., Norby, Bob., Bartlett, Paul C., Takeshima, Shin-nosuke., Aida, Yoko., Grooms, Daniel L. "Breeding Bulls as a Source of Bovine Leukemia Virus for Beef Herds." Journal of the American Veterinary Medical, 254(11), 1335-1340. 2019
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Ruggiero, V. J., Bartlett, P. C. Single-use hypodermic needles and obstetric sleeves failed to reduce bovine leukemia virus transmission in three dairy herds. The Bovine Practitioner, 2019; 53(2).
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Ruggiero, Vickie J., Benitez, Oscar J., Yun-Long Tsai., Pei-Yu Alison Lee., Chuan-Fu Tsai., Yu-Chun Lin., Hsiao-Fen Grace Chang., Hwa-Tang Thomas Wang., Bartlett, Paul C. "On-site detection of bovine leukemia virus by a field- deployable automatic nucleic extraction plus insulated isothermal polymerase chain reaction system." Journal of virological methods, 259 (2018): 116-121.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Ruggiero VJ, Norby B, Benitez OJ, Hutchinson H, Sporer KRB, Droscha C, Swenson CL, and Bartlett PC. Controlling bovine leukemia virus in dairy herds by identifying and removing cows with the highest proviral load and lymphocyte counts. Journal of Dairy Science. 2019. 102(10):9165-9175.
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Rebecca M. LaDronka, Samantha Ainsworth, Melinda J. Wilkins, Bo Norby,Todd M. Byrem and Paul C. Bartlett. Prevalence of bovine leukemia virus antibodies in U.S. dairy cattle. Veterinary Medicine International. Volume 2018, Article ID 5831278, 8 pages. 2018
|
Progress 04/15/18 to 04/14/19
Outputs
Target Audience:U.S. Dairy producers, veterinarians and animal scientists. Changes/Problems:This intervention of identifying and removing the most highly infectious cattle was not recognized when we wrote the initial grant application, so the field trial using this approach were not started until the beginning of year 3. What opportunities for training and professional development has the project provided?We still have four PhD and two masters graduate students working on this BLV project. Three assistant professors have joined our BLV research group. We are collaborating with Japanese BLV researchers to improve the interpretation of our results, and are also working with three private firms developing BLV diagnostic technology. How have the results been disseminated to communities of interest?Having completed their courses and data collection, two of our PhD students will now devote their time to producing scientific and lay publications and to giving presentations at producer meetings and scientific conferences. Our website (WWW.BLVUSA.com) will be continually expanded and improved in the years ahead as our results are published. We continued work with our Extension service and our industry partners at NorthStar Laboratories Cooperative and Advanced Animal Diagnostics to offer a BLV testing Extension program. What do you plan to do during the next reporting period to accomplish the goals?We will analyze the data from the national survey to produce papers and presentations (see above). The results of the field trials will be analyzed and published. We will expand and continue the intervention field trial to reduce BLV transmission by identification and removal of the most highly infectious cattle. The Extension demonstration project will continue and will be described in a scientific publication.
Impacts
What was accomplished under these goals?
Our national dairy survey provided estimates of bovine leukemia virus prevalence throughout the nation, and will be the database used to estimate BLV economic impact on milk production and cow longevity. Our field trials assessing the control of BLV are being published, and one large trial is ongoing. The most encouraging intervention involves the identification and removal of high proviral load cattle (super-shedders) which appear to be responsible for most transmission. Our educational and extension programs continue. Objective 1: We completed our national survey of 4,120 dairy cows from 103 commercial dairy herds in 11 states across the U.S. 94.2% of herds had at least one BLV ELISA antibody-positive cow. The average within-herd standardized apparent prevalence was 46.5%. Lactation-specific prevalence increased with increasing lactation number, from 29.7% in first lactation cows to 58.9% in the 4th and greater lactation cows. Each 10% increase in prevalence was associated with a 430.7 lb (195.8 kg) loss in rolling herd average milk production, which is a greater loss than what was found in our 2010 study of Michigan herds. A survival analysis is underway to measure the impact of BLV on cow longevity (lifespan) and we are conducting a herd and cow-level analysis of the impact of BLV on milk production. Objective 2 and 3: BLV Intervention Field Trials: Study 1: We completed an intervention field trial in which BLV-negative cattle were randomly assigned to: 1) always receive a new hypodermic needle and a new reproductive examination sleeve or 2) always receive needles and sleeves shared with their BLV-infected herdmates. The preliminary results showed no statistically significant difference in rate of new BLV infections between the two groups: 22.7% (102/448.5) new infections in the intervention group versus 20.0% (88/440) new infections in the negative control group. Manuscript in review. Study 2: Three dairy farms with an initial BLV prevalence of < 5% attempted to eradicate BLV from their milking herds by culling or separating their ELISA-positive cattle based on milk ELISA testing. Two of the three herds eradicated BLV from their milking herd by their 3rd and 4th test, respectively, but both herds were eventually re-infected when their own BLV-positive heifers entered their milking herds. The third herd also experienced increased prevalence due to of incoming infected heifers. We concluded that removing ELISA-positive cattle can eradicate BLV from a milking herd, but young stock must also be free of BLV to prevent re-introduction of the disease (manuscript in review). Study 3: Three herds are participating in a field trial using three semi-annual diagnostic tests (milk ELISA, BLV proviral load, and blood lymphocyte count) to reduce transmission by identifying the most highly infectious cattle for culling or separation. The first 2 herds have been on the trial for 2.5 years, and the third herd has been on trial for 2 years. The herd which most aggressively culled animals with both high proviral load and high lymphocyte counts (super-shedders) has decreased their overall herd prevalence from 64% (127/199) to 14%. The second herd had their prevalence decrease from 58% (96/165) to 27%. The third herd went from 66% (50/76) to 45% prevalence. The decrease in prevalence in the 3 herds together was highly significant by the extended Mantel-Haenszel chi-square test for trend. The manuscript is accepted for publication pending minor revisions. Because this intervention appears to be highly effective, this field trial was expanded by the addition of 6 additional herds. Other studies: We found decreased total IgA concentrations in milk and saliva of BLV ELISA-positive cows (Manuscript in progress). Previously reported host alleles associated with BLV disease progression (proviral load and lymphocytosis) are being evaluated in our ongoing genetic studies of cows from two of our field trials. Samples from white-tailed deer show no serologic evidence of BLV infection and PCR testing is pending. The database from our field trials is providing us an opportunity to compare the results of 3 diagnostic tests for BLV: 1) the serum or milk ELISA test for gp51 BLV antibodies (our best measure of previous exposure), 2) the lymphocyte count (our best indication of immune disruption) and 3) the qPCR proviral load (thought to be our best estimate of the infectivity of the blood and other body fluids). A smaller study of about 200 cows is being conducted to compare the results of six BLV diagnostic tests. Several of our field trials required semi-annual testing of our study herds. This ELISA testing was done as close as possible to November 1st and May 1st of each year, enabling us to compare rates of new BLV infections between the summer biting-fly season and the winter months when Michigan has no biting flies. Objective 4: Education. The results from our previous studies were analyzed to estimate the cost of BLV on one of our field study herds. The analysis is shown on our BLVUSA website http://blv.msu.edu/impact/index.html. Reduction in milk production and cow longevity were the greatest loss components. The total annual cost was estimated at $38,000 for each 100 milking cows. This economic analysis will be the basis of future educational and training scenarios. Our website at www.BLVUSA.com is now being updated based on recent developments in BLV research. Spanish and English versions will be available. Objective 5: Extension: A total of 80 interested dairy farmers participated in our Extension program. Upon receipt of their testing results, a consultation with the Extension Dairy Educator was held with the farmer to identify ways to reduce the spread of the disease within their herd. Changes to reduce transmission on farms included single use of needles, single use of examination sleeves and changes in calf feeding. Testing was performed in years 2016-2018. Some farms were able to reduce the prevalence in their herds, while others, in spite of actions to reduce risk, made either no substantial improvement or even saw increasing prevalence. Approximately 10% of herds in both years were negative for BLV. The testing provided great opportunity for education and often led to participate in further research projects.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Frie MC, Droscha CJ, Greenlick AE, Coussens PM. MicroRNAs Encoded by Bovine Leukemia Virus (BLV) Are Associated with Reduced Expression of B Cell Transcriptional Regulators in Dairy Cattle Naturally Infected with BLV. Front Vet Sci. 2018 Jan 15;4:245
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Frie MC, Sporer KRB, Kirkpatrick BW, Coussens PM. T and B cell activation profiles from cows with and without Johne's disease in response to in vitro stimulation with Mycobacterium avium subspecies paratuberculosis. Vet Immunol Immunopathol. 2017 Dec;193-194:50-56.
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Bartlett, Paul, LaDronka, R., Ruggiero, V. and Hutchinson, H. What dairy veterinarians should know about bovine leukemia virus. 2017. The Bovine Practitioner Vol 52:No 1, 2-6.
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Ruggiero VJ, Benitez OJ, Tsai YL, Lee PA, Tsai CF, Lin YC, Chang HG, Wang HT, Bartlett P. On-site detection of bovine leukemia virus by a field-deployable automatic nucleic extraction plus insulated isothermal polymerase chain reaction system. J Virol Methods. 2018 Sep;259:116-121.
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Rebecca M. LaDronka, Samantha Ainsworth, Melinda J. Wilkins,Bo Norby,Todd M. Byrem and Paul C. Bartlett. Prevalence of bovine leukemia virus antibodies in U.S. dairy cattle. Veterinary Medicine International. Volume 2018, Article ID 5831278, 8 pages.
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Paul Bartlett, Vickie Ruggiero, Phil Durst, Casey Droscha, Kelly Sporer, Todd Byrem. Stop Super-shedders in their tracks. Hoards Dairyman. October 25, 2018. 629.
- Type:
Journal Articles
Status:
Under Review
Year Published:
2019
Citation:
Ruggiero, V. J., Norby, B., Benitez, O. J., Hutchinson, H., Sporer, K. R. B., Droscha, C., Swenson, C. L., Bartlett, P. C. Controlling bovine leukemia virus in dairy herds by identifying and removing cows with the highest proviral load and lymphocyte counts. Journal of Dairy Science [in review].
- Type:
Journal Articles
Status:
Under Review
Year Published:
2019
Citation:
Ruggiero, V. J., Bartlett, P. C. Single-use hypodermic needles and obstetric sleeves failed to reduce bovine leukemia virus transmission in three dairy herds. Bovine Practitioner [in review].
- Type:
Journal Articles
Status:
Under Review
Year Published:
2019
Citation:
Ruggiero, V. J., Bartlett, P. C. Control of bovine leukemia virus in three U.S. dairy herds by culling ELISA-positive cows. Veterinary Medicine International [in review].
- Type:
Journal Articles
Status:
Other
Year Published:
2019
Citation:
Ruggiero, V. J., Dziuba, M. M., Wilson, C., Greenlick, A., Bartlett, P. C., Coussens, P. Immunoglobulin levels are altered in milk and saliva, but not serum, of bovine leukemia virus antibody-positive dairy cows [in preparation].
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Hutchinson, H. C., Norby, B., Erskine, R., Byrem, T., Bartlett, P. (2017, December). Risk of New Infections with Bovine Leukemia Virus on Michigan Dairy Herds. 98th Annual Meeting of the Conference of Research Workers in Animal Diseases, Chicago, IL
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Ruggiero, V. J., Benitez, O. J., Hutchinson, H., Norby, B., Bartlett, P. C. Selective removal of high proviral load cows to control bovine leukemia virus in dairy herds. Conference of Research Workers in Animal Diseases, December 2017. [Oral Presentation] Chicago, IL
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
C. Kellogg, B. Norby, C. Droscha, L. Sordillo. Impact of bovine leukemia virus on leukocyte counts and ELISA status through dry-off & parturition in dairy cattle. 12/3/2018. Conference of Research Workers in Animal Diseases, Chicago, IL
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
B. Norby, P. Bartlett, P. Coussens, R. Erskine, C. Kellogg, L. Sordillo. Impact of Bovine Leukemia Virus Infection on Disease Incidence and Severity in Dairy Cattle. 12/3/2018. Conference of Research Workers in Animal Diseases, Chicago, IL
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
H.C. Hutchinson, B. Norby, C. Droscha, C. Kellogg, P.C. Bartlett. Proviral, antibody and lymphocyte dynamics in steers following intramuscular challenge with Bovine Leukemia Virus. 12/2/2018. Conference of Research Workers in Animal Diseases, Chicago, IL
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
K.R. Sporer, C.J. Droscha, V.J. Ruggiero, T.M. Byrem, P.M. Bartlett.
Development of a novel assay for identifying highly infectious cows with bovine leukosis 12/2/2018. Conference of Research Workers in Animal Diseases, Chicago, IL
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
P.M. Coussens, M.C. Frie, M.E. Cooke, B.W. Kirkpatrick. Bovine leukemia virus alters the status of T cells in PBMCs from infected cattle. 12/2/2018. Conference of Research Workers in Animal Diseases, Chicago, IL
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
M. Dziuba, A. Greenlick, V. Ruggiero, P.C. Bartlett, C. Wilson, P.M. Coussens.
Effects of bovine leukemia virus on antibody levels in milk, serum, and saliva 12/2/2018. Conference of Research Workers in Animal Diseases, Chicago, IL
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
R.M. LaDronka, S. Ainsworth, M.J. Wilkins, B. Norby, T.M. Byrem, P.C. Bartlett.
Bovine leukemia virus in U.S. dairy cattle: update on descriptive epidemiology from a national survey. 12/3/2018. Conference of Research Workers in Animal Diseases, Chicago, IL
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
V.J. Ruggiero, B. Norby, R. Erskine, K.R. Sporer, C.J. Droscha, P.C. Bartlett.
Evaluating control of bovine leukemia virus in dairy herds. 12/3/2018. Conference of Research Workers in Animal Diseases, Chicago, IL
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
O.J. Benitez, B.J. Norby, D.J. Grooms, P.J. Bartlett. Effect of bovine leukosis virus on beef cow longevity. 12/3/2018. Conference of Research Workers in Animal Diseases, Chicago, IL
|
Progress 04/15/17 to 04/14/18
Outputs
Target Audience:U.S. Dairy producers, veterinarians and animal scientists Changes/Problems:Enrollment of herds in our national survey (Objective 1) was slowed when we moved to the western states where the DHI structure was very different and the software needed to monitor the cows for 2 years was different from what is used in the rest of the country. The most promising intervention has been the use of lymphocyte count and proviral load to identify BLV super-shedders for culling or segregation. This intervention was not recognized when we wrote the initial grant application, so the field trial was not started until the beginning of year 3 of the 5-year project. What opportunities for training and professional development has the project provided?We have three graduate students working on this BLV project and two more working on BLV-funded through other funding sources. Three assistant professors are joining our BLV research group. We are collaborating with Japanese BLV researchers to improve the interpretation of our results, and are also working with three private firms developing BLV diagnostic technology. How have the results been disseminated to communities of interest?Having completed their courses and data collection, two of our PhD students will now devote their time to producing scientific and lay publications and to giving presentations at producer meetings and scientific conferences. Our website (WWW.BLVUSA.com) will be continually expanded and improved in the years ahead as our results are published. We continued work with our Extension service and our industry partners at NorthStar Laboratories Cooperative and Advanced Animal Diagnostics to offer a BLV testing Extension program. What do you plan to do during the next reporting period to accomplish the goals?We will analyze the data from the national survey to produce papers and presentations (see above). The results of the field trials will be analyzed and published. We will expand and continue the intervention field trial to reduce BLV transmission by identification and removal of the most highly infectious cattle. The Extension demonstration project will continue and will be described in a scientific publication.
Impacts
What was accomplished under these goals?
Our national dairy survey provided estimates of bovine leukemia virus prevalence throughout the nation, and will be the basis for research regarding BLV economic impact on milk production and cow longevity. Our field trials addressing the control of BLV are now largely complete and the results are being analyzed in preparation for publication. The most encouraging intervention involves the removal of high proviral load cattle (super-shedders) which appear to be responsible for most transmission. Our educational and extension programs continue to expand, and a description of our Extension demonstration project will be published. Obj. 1: We completed our national survey of 4,120 dairy cows from 103 commercial dairy herds in 11 states across the U.S. 94.2% of herds had at least one BLV ELISA antibody-positive cow. The average within-herd standardized apparent prevalence was 46.5%. Lactation-specific prevalence increased with increasing lactation number, from 29.7% in first lactation cows to 58.9% in the 4th and greater lactation cows. No significant differences were observed in region, state, breed or herd size. These results are consistent with a historical trend of increasing BLV prevalence among U.S. dairy cattle. Each 10% increase in prevalence was associated with a 430.7 lb (195.8 kg) loss in rolling herd average milk production, which is a greater loss than what was found in our 2010 study of Michigan herds. Obj. 2 & 3: Study 1: We completed an intervention field trial in which BLV-negative cattle were randomly assigned to: 1) always receive a new hypodermic needle and a new reproductive examination sleeve or 2) always receive shared needles and sleeves with their BLV-infected herdmates. The preliminary results showed no statistically significant difference in rate of new BLV infections between the two groups: 20.2% (53/262) new infections in the intervention group versus 16.4% (40/244) new infections in the negative control group. Study 2: Three dairy farms with an initial BLV prevalence of < 5% attempted to eradicate BLV from their milking herds by culling or separating their ELISA-positive cattle based on milk ELISA testing. Two of the three herds eradicated BLV from their milking herd by their 3rd and 4th test, respectively, but both herds were eventually re-infected when their own BLV-positive heifers calved and entered the milking herd. The third herd experienced increased prevalence due to a large flux of incoming infected heifers. We concluded that removing ELISA-positive cattle can eradicate BLV from a milking herd, but young stock must also be free of BLV to prevent re-introduction of the disease. Study 3: Three herds are participating in a field trial using three semi-annual diagnostic tests (milk ELISA, BLV proviral load, and blood lymphocyte count) to reduce transmission by identifying the most highly infectious cattle for culling or separation. The first 2 herds have been on the trial for 2 years, and the third herd has been on trial for 1.5 years. The herd which most aggressively culled animals with both high proviral load and high lymphocyte counts (super-shedders) has decreased their overall herd prevalence from 64% (127/199) to 19%. The second herd had their prevalence decrease from 58% (96/165) to 37%. The third herd went from 65% (49/75) to 48% prevalence. The decrease in prevalence in the 3 herds together was highly significant by the extended Mantel-Haenszel chi-square test for trend. Because this intervention appears to be highly effective, this field trial is being expanded by the addition of 5 or 6 additional herds of varying sizes and management styles. The database from this intervention project is providing us an unprecedented opportunity to compare the results of 3 diagnostic tests for BLV: 1) the serum or milk ELISA test for gp51 BLV antibodies (our best measure of previous exposure), 2) the lymphocyte count (our best indication of immune disruption) and 3) the qPCR proviral load (thought to be our best estimate of the infectivity of the blood and other body fluids). Several of our field trials required semi-annual testing of our study herds. This ELISA testing was done as close as possible to November 1st and May 1st of each year, enabling us to compare rates of new BLV infections between the summer biting-fly season and the winter months when Michigan has no biting flies. We have conducted a genetic comparison between identified persistently high proviral load cattle and aged-matched herdmates that have been ELISA-positive for over 1 year without showing elevation in proviral load or lymphocyte count. Preliminary results suggest there may be some alleles of interest. These results are awaiting analysis and publication. The results from our previous studies were analyzed to estimate the cost of BLV on one of our field study herds. The analysis is shown on our BLVUSA website http://blv.msu.edu/impact/index.html. Reduction in milk production and cow longevity were the greatest loss components. The total annual cost was estimated at $38,000 for each 100 milking cows. This economic analysis will be the basis of future educational and training scenarios. Obj. 4: Several new sections and videos were added to our BLV webpage at www.BLVUSA.com. The video lectures are designed for integration into online or classroom instruction. Learning exercises are being developed where students can estimate BLV economic impact for any particular dairy herd, and use this estimate as a basis for discussing the control of BLV transmission. A lecture given at the 2017 U.S. Animal Health Association meeting will be re-recorded for the website. Obj. 5: Our BLV participatory research project continues into a 4th year. Dairy producers paid a reduced-cost for a BLV herd profile, which is an ELISA test of 40 cows (10 from each of 4 lactation groups) and completed a BLV risk assessment survey. Producers then consulted with our Extension staff and decided on management changes to reduce BLV transmission. A consultation was also provided with their herd veterinarian. Participating producers are receiving follow-up BLV profiles and Extension consultations to discuss their progress in controlling BLV. In there were 42 farms started in 2015 and another 38 herds started in 2016. Annual testing on all these herds continued in 2017 and 2018. A 4-H presentation with contests and prizes is being developed and organized for 2018.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Frie, M.C., Sporer, K.R., Benitez, O.J., Wallace, J.C., Droscha, C.J., Bartlett, P.C., Coussens, P.M., 2017. Dairy cows naturally infected with bovine leukemia virus (BLV) exhibit abnormal B and T cell phenotypes after primary and secondary exposure to keyhole limpet hemocyanin. Frontiers in Veterinary Science, 4:112.
- Type:
Journal Articles
Status:
Awaiting Publication
Year Published:
2018
Citation:
Frie, M.C., Droscha, C.J., Greenlick, A.E., Coussens, P.M. MicroRNAs encoded by bovine leukemia virus are associated with reduced expression of B cell transcriptional regulators in dairy cattle naturally infected with BLV. Submitted to Frontiers in Veterinary Science.
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Bartlett, P.C., LaDronka, R., Ruggiero, V. et al. Bovine leukemia virus: lost milk and hidden costs. Hoards Dairyman. November 2017, 688 689.
- Type:
Book Chapters
Status:
Published
Year Published:
2017
Citation:
LaDronka, R. M. (2017). Bovine leukemia virus. In C. L. Chase, K. A. Lutz, E. C. McKenzie, & A. Tibary (Eds.), Blackwells five-minute veterinary consult: Ruminant (2nd ed.) (pp. 105-106). Hoboken, NJ: Wiley Blackwell.
- Type:
Journal Articles
Status:
Submitted
Year Published:
2018
Citation:
Ruggiero, V. J., Benitez, O. J., Yun-Long, T., Lee, P. A., Tsai, C. M., Lin, Y., Chang, H. G., Wang, H. T., Bartlett, P. C. Efficient on-site detection of bovine leukemia provirus in bovine whole blood. Submitted for publication.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2017
Citation:
Bartlett, Paul C. Bovine Leukemia Virus in the U.S.: Impact and Options for Control. US Animal Health Association Annual Meeting. San Diego, CA October, 2017 Oral Presentation and Proceedings.
- Type:
Journal Articles
Status:
Submitted
Year Published:
2018
Citation:
Prevalence of bovine leukemia virus antibodies in U.S. dairy cattle. Rebecca M. LaDronka, Samantha Ainsworth, Melinda J. Wilkins, Bo Norby, Todd M. Byrem, Paul C. Bartlett. Submitted to the J. of the Am. Vet Med Assoc
- Type:
Journal Articles
Status:
Accepted
Year Published:
2018
Citation:
Paul C. Bartlett, Rebecca LaDronka, Vickie Ruggiero, Holden Hutchinson. What dairy veterinarians should know about bovine leukemia virus. The Bovine Practitioner. Accepted for publication. 2018
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Frie M., Sporer K., Coussens P. (2017). Dairy cattle naturally infected with bovine leukemia virus exhibit abnormal adaptive immunity after primary and secondary challenges with keyhole limpet hemocyanin. Immunology 2017. Washington, DC. (Oral)
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
LaDronka, R.M., Maeroff, J.E., Norby, B., Byrem, T.M., Erskine, R.J., & Bartlett, P.C. Somatic cell counts in bovine leukemia virus positive cows. October 6, 2017. 27th Annual Phi Zeta Research Day, Michigan State University, College of Veterinary Medicine. East Lansing, Michigan.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Hutchinson, H. C., Norby, B., Erskine, R., Byrem, T., Bartlett, P.(2017, October 6). Analysis of the Risk For Seroconversion to Bovine Leukemia Virus Among Michigan Dairies. Michigan State University College of Veterinary Medicine Phi Zeta Research Day. E. Lansing, MI.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Hutchinson, H. C. (2017, November 3). Bovine Leukemia Virus: Overview of Incidence in Michigan Dairy Cattle, Cervid Surveillance, and a Controlled Infection Study. Michigan State University Comparative Medicine and Integrative Biology Research Forum, E. Lansing, MI
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Hutchinson, H. C., Norby, B., Erskine, R., Byrem, T., Bartlett, P. (2017, December). Risk of New Infections with Bovine Leukemia Virus on Michigan Dairy Herds. 98th Annual Meeting of the Conference of Research Workers in Animal Diseases, Chicago, IL.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Ruggiero, V. J., Droscha, C. J., Bartlett, P. C. Genetic associations with BLV disease phenotypes in dairy cattle. Michigan State University Phi Zeta Research Day, 2017. [Poster] E. Lansing, MI.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Ruggiero, V. J., Benitez, O. J., Hutchinson, H., Norby, B., Bartlett, P. C. Selective removal of high proviral load cows to control bovine leukemia virus in dairy herds. Conference of Research Workers in Animal Diseases, December 2017. [Oral Presentation] Chicago, IL
|
Progress 04/15/16 to 04/14/17
Outputs
Target Audience:U.S. Dairy producers, veterinarians and animal scientists Changes/Problems:Several of our studies are complete and we now need to do the statistical analyses and publish papers. What opportunities for training and professional development has the project provided?We have three graduate students working on this BLV project and two more working on BLV funded through other grants. How have the results been disseminated to communities of interest?(See objectives 4 and 5 above) What do you plan to do during the next reporting period to accomplish the goals?(See above) We will continue and conduct the field trials, analyze the data from the national survey and expand our education and Extension activities. We are on track to meet each of our objectives.
Impacts
What was accomplished under these goals?
Objective 1: National Survey: Enrollment has been completed with 103 herds in 11 states. Herd size ranged from 59 to 7453 cows with a mean of 548 cows. Milk samples were collected from an average of 40 cows per herd (4120 cows total) and tested for BLV antibodies via ELISA by our industry partners at Antel BioSystems. 95.4% of herds had at least one positive animal in the sample tested.The mean lactation-specific prevalence for the 1st, 2nd, 3rd, and 4th+ lactations were 29.9%, 43.2%, 54.2%, and 59.2% respectively. Preliminary analysis of herd level production data showed that each 10% increase in prevalence was associated with a 430.7 lb (195.8 kg) loss in RHA. Immunology Studies: In 2016, two separate studies were conducted to investigate if BLV+ and BLV- cows responded equally to immune stimulation. In 2017, the analysis of differences in primary and secondary memory immune responses in BLV+ and BLV- dairy cows was completed. A new study is in progress to investigate BLV microRNAs target IGJ expression. Objective 2 and 3: BLV Intervention Field Trials: Hypodermic needles and reproductive exam sleeves: Three herds have completed six study-years in the intervention field trial in which BLV-negative cattle were randomly assigned to always receive the intervention treatment of a new hypodermic needle and new reproductive examination sleeve or to always received shared needles as sleeves with the rest of the herd (negative controls). Data analysis is ongoing to determine the effectiveness of the intervention by comparing the intervention group to the control group with regard to the rate of new BLV infections per 100 cow months at risk. Traditional BLV Control by ELISA Test and Removal: Three herds with initial BLV prevalence of less than 5% participated in a demonstration project to eradicate the BLV via milk ELISA testing with culling or segregation of ELISA-positive cattle. The overall conclusions are that a closed herd must be established before attempting BLV eradication, and that ELISA testing of the heifers will also be needed to prevent them from spreading the infection when they eventually enter the milking herd. Super-shedder study: Three herds are participating in a demonstration field trial using three diagnostic tests (milk ELISA, BLV proviral load, and blood lymphocyte count) to control BLV via direct culling and segregation of cattle. One herd is aggressively culling animals with both high proviral load and high lymphocyte counts (super-shedders), and has decreased overall herd prevalence by 20%. A second herd, which has been less aggressive, has seen a decrease of 9%. The third and newest herd has experienced a 1% decrease in prevalence their first 6 months on the project. These results will be published in 2017 or 2018. The database from this intervention project is providing us an unprecedented opportunity to compare the results of the three predominant diagnostic tests for BLV, 1) the serum or milk ELISA test for gp51 BLV antibodies (our best measure of previous exposure), 2) the lymphocyte count (our best indication of immune disruption) and 3) the qPCR proviral load (our best measure of the infectivity of the blood and other body fluids). Rate of new BLV infections in summer versus winter: Several of our field trials required semi-annual testing of our study herds. This ELISA testing was done as close as possible to November 1st and May 1st of each year so that we would could calculate a rate of new BLV infections (cases per 100 cow-months at risk) during the summer biting-fly season for comparison to the rate of new BLV infections obtained in the winter months when Michigan has no biting flies. A publication is planned regarding the comparison of these rates to help us ascertain the relative importance of BLV fly transmission in Michigan. New PCR for BLV: This study evaluated the performance of a field-deployable automatic nucleic acid-extraction/insulated isothermal PCR (iiPCR) system for on-site BLV detection in comparison with a conventional laboratory real-time PCR (rt-PCR ). The new PCR system was found to perform at least as well as a conventional laboratory-based rt-PCR system for detection of BLV-infection in whole blood. These results are being prepared for publication in the summer of 2017. Genetic analysis of high vs low proviral load cattle: We will conduct a genetic comparison between identified persistently high PVL cattle and aged-matched herdmates that have been ELISA-positive for over 1 year without showing any elevation in PVL or lymphocyte count. These two types of cows will have blood submitted for sequence-based typing of the BoLA loci to determine BoLA haplotypes. If associations are found, selected samples will be analyzed using the BovineHD DNA SNP array featuring over 777,000 annotated SNPs to discover other possible contributing genetic variants. Objective 4: Education. Our new BLV webpage is at www.BLVUSA.com was re-written this year and moved to a different server where we will have greater editorial control. Several new sections and videos were added. The video lectures are suitable for integration into online or classroom instruction. We plan to write some learning exercises where students can estimate economic impact and learn how to advise dairy clients on how they can control BLV. Economic study: We used the results from our previous studies to estimate the cost of BLV on one of our field study herds. The analysis is shown on our BLVUSA website http://blv.msu.edu/impact/index.html A partial budget of BLV-associated losses is shown for this 140 cow herd. Reduction in milk production and cow longevity were the greatest loss components. The total annual cost was estimated at $38,000 for each 100 milking cows. This economic analysis will be the basis of future educational and Extension papers and learning scenarios. Objective 5: Extension: The analysis of the 2015 Extension project was completed in 2016. This was a community research project in which the participating 42 herds submitted milk samples for BLV ELISA testing from the 10 most recently calved cows in their 1st, 2nd, 3rd and 4+ lactations). They then implemented management changes and then re-tested another 40 cows about a year later. We found that 88% of herds had at least one BLV-positive animals on the first test and 37% of all tested animals were ELISA positive. There was a strong association with lactation number. The lactational prevalence rates for lactations 1, 2, 3 and 4+ were 19%, 31%, 45% and 52%, respectively. The 2016 Extension project hypothesized that dairy herds with below average cow age may have a higher than average prevalence of BLV. This is due to poor longevity among the BLV infected cattle. We decided to use the herd's average cow age as an indicator of herds with potentially high rates of BLV. For our 2016 Extension project, we therefore targeted Michigan herds on DHI with average cow age in the lowest 25 percentiles. We found that 91% of the herds had at least one cow positive for BLV, the overall prevalence was 38% and the lactational prevalence rates for lactations 1, 2, 3 and 4+ were 14, 27, 43 and 49%, respectively. BLV Survey of White-tailed Deer: While virtually all ruminants are susceptible to BLV infection, it is completely unknown what proportion of our wild white-tailed deer population might be infected with BLV. We have an active bovine tuberculosis control program in Michigan in which lymph nodes from deer are routinely tested for evidence of tuberculosis. The above described iiPCR system will be used to survey for BLV infection in deer lymph nodes collected as part of this tuberculosis surveillance system.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
B. Norby, P. C. Bartlett,T. M. Byrem, and R. J. Erskine. Effect of infection with bovine leukemia virus on milk production in Michigan dairy cows. 2016. J. Dairy Sci. 99:110.
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
Frie MC, Sporer KR, Wallace JC, Maes RK, Sordillo LM, Bartlett PC, Coussens PM. 2016. Reduced humoral immunity and atypical cell-mediated immunity in response to vaccination in cows naturally infected with bovine leukemia virus. Vet Immunol Immunopathol 182:125-135.
- Type:
Websites
Status:
Published
Year Published:
2017
Citation:
Frie, Meredith. 2017. Why we need to keep an eye on whether a blood infection in cattle is linked to breast cancer in humans. The Conversation.
https://theconversation.com/why-we-need-to-keep-an-eye-on-whether-a-blood-infection-in-cattle-is-linked-to-breast-cancer-in-humans-70318
- Type:
Journal Articles
Status:
Submitted
Year Published:
2017
Citation:
Frie MC, Sporer KRB, Benitez OJ, Wallace JC, Droscha CJ, Bartlett PC, Coussens PM. 2017. Dairy cows naturally infected with bovine leukemia virus (BLV) exhibit abnormal B and T cell phenotypes after primary and secondary exposure to keyhole limpet hemocyanin. Submitted to Frontiers in Veterinary Science.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2016
Citation:
Frie M, Sporer K, Wallace JC, Maes R, Sordillo L, Bartlett P, Coussens P. 2016. Dairy cows naturally infected with bovine leukemia virus demonstrate abnormal B and T cell responses to routine vaccination. Conference of Research Workers in Animal Diseases. Chicago, IL.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2016
Citation:
Frie MC, Sordillo LM, Bartlett PC, Coussens PM. 2016. Reduced memory responses to vaccination in cows naturally infected with bovine leukemia virus. Immunology 2016, Seattle, WA.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Frie M, Sporer K, Coussens P. (2017). Dairy cattle naturally infected with bovine leukemia virus exhibit abnormal adaptive immunity after primary and secondary challenges with keyhole limpet hemocyanin. Immunology 2017. Washington, DC.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2015
Citation:
Frie, M.C., Sordillo, L.M., Bartlett, P.C., Coussens, P.M. "Reduced antigen-specific antibody levels in cows naturally infected with bovine leukemia virus". Conference of Research Workers in Animal Diseases, December 2015, Chicago, IL. Oral presentation
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2016
Citation:
Frie M, Sporer K, Wallace JC, Maes R, Sordillo L, Bartlett P, Coussens P. 2016. Dairy cows naturally infected with bovine leukemia virus demonstrate abnormal B and T cell responses to routine vaccination. Conference of Research Workers in Animal Diseases. Chicago, IL.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2016
Citation:
V.J. Ruggiero, O.J. Benitez, Y. Tsai, C. Tsai, Y. Lin, P.A. Lee, H.G. Chang, H.T. Wang, P. Bartlett; A field-deployable nucleid acid extraction/PCR system detected bovine leukemia virus proviral DNA in blood with a performance equivalent to a laboratory real-time PCR system . Conference of Research Workers in Animal Diseases, December 2016, Chicago, IL. Oral presentation.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2016
Citation:
R.M. LaDronka, B. Norby, T.M. Byrem, R.J. Erskine, P.C. Bartlett. Impact of bovine leukemia virus on herd level production indicators on US dairy farms. Conference of Research Workers in Animal Diseases, December 2016, Chicago, IL. Oral presentation.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Durst, Phil. BLV Control in Michigan Dairy Herds. Dairyland Testing Association at their Annual Meeting, January 24, 2017
- Type:
Other
Status:
Published
Year Published:
2016
Citation:
Presentations on Colostrum Quality included discussion about colostrum from BLV+ dams at 6 locations around MI.
- Type:
Other
Status:
Published
Year Published:
2016
Citation:
Consultations: As part of the Extension project, we met on 35 farms with 52 farm personnel and 28 veterinarians for an average 1.25 hours each to discuss their BLV testing results and develop a plan for controlling BLV.
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Progress 04/15/15 to 04/14/16
Outputs
Target Audience:U.S. Dairy producers, veterinarians and animal scientists Changes/Problems:The field trial regarding employment of single-use needles and sleeves will be delayed due to the necessary exclusion of data. An entire year of data from a small herd will need to be excluded because the herd owner became convinced that the single-use needles and sleeves was a good idea and she admitted that, contrary to the study protocol, she had been using single-use needles and sleeves on the control cows as well. We also lost half and year of data from a large herd that, on one of our monitoring visits, admitted that they had been using the same sleeve on all the BLV-negative cattle rather than changing the sleeve between each cow like they were supposed to have done. To prevent future deviations from the study protocol, we will increase the number of herd visits to review the protocol and monitor protocol compliance. Our national survey (Objectives 1 and 2) was delayed as we moved to states with different DHI organizational structures and software. It was impossible to adequately represent the western states like we had originally intended. In compensation, additional herds were added from other regions of the country. What opportunities for training and professional development has the project provided?We have three graduate students working on our BLV research, and a fourth student will enroll in fall 2016. Two are working exclusively on BLV in dairy cattle, one is primarily working on BLV immunology, and the fourth study will be working primarily on BLV in beef cattle. All these graduate students are involved in our Extension and educational efforts. We also employ two veterinary students as student employees. We are collaborating with Japanese BLV researchers to improve the interpretation of our results, and also to look at the genetic differences between infected cows that develop lymphocytosis and those that maintain a normal hematological profile. We are also working with three private firms that are developing BLV diagnostic technology. One of these firms is developing a rapid method for determining blood lymphocyte counts, one is developing a BLV PCR diagnostic test and one is working to improve BLV ELISA technology and interpretation. How have the results been disseminated to communities of interest?Yes. See objectives 4 and 5 above. What do you plan to do during the next reporting period to accomplish the goals?We will continue and expand the field trials, complete the national survey and expand our education and Extension activities. We are on track to meet each of our objectives. We will initiate work on the following planned publications: Graduate Student #1: 1. National BLV survey: Methodology, prevalence, descriptive epidemiology. 2. BLV impact on milk production. Two-level hierarchical model. 3. BLV impact on somatic cell count. Two-level hierarchical model. 4. BLV impact on reproductive performance. 5. Association between BLV prevalence and herd management factors 6. Participatory research program to control BLV in dairy herds Graduate Student #2: 1. Comparisons among BLV diagnostic tests: ELISA, proviral load and lymphocyte count. 2. Impact of single-use hypodermic needles and transrectal palpation gloves on the rate of new BLV infections 3. Control of BLV via test and cull procedures on U.S. dairy farms. 4. Control of BLV via testing by ELISA, proviral load and lymphocyte count. 5. Targeted extension program for controlling BLV in U.S. dairy herds
Impacts
What was accomplished under these goals?
Administration:Our next External Advisory Panel, planned for August 2016, will include our investigators, industry partners (NorthStar Laboratories / Antelbio Systems and GeneReach) and Dr. Takeshima representing our Japanese collaborators. In this meeting we will critique our current BLV projects and discuss our plans to continue our objectives for research, education and Extension. Objective 1: We began enrolling dairy herds in our national BLV study in June of 2014. As of May 2016, 85 herds have been enrolled from (Michigan, Minnesota, New York, Pennsylvania, Ohio, Idaho, Utah, North Carolina and Wisconsin). Management surveys were obtained from each herd and milk from 40 of their cows (the 10 most recently calved in lactations 1, 2, 3 and 4+) were tested for ELISA BLV antibodies through their local DHI organization. Permission was granted for access to their DHI records and these cows will be tracked prospectively for the next two years for variables regarding longevity, production and reproduction. The average size of milking herds enrolled is 571 cattle, ranging from 59 to 7,453 cows. We will add an additional 30 herds by June 2016 from Michigan, New York and Minnesota. The average estimated within-herd prevalence (based on BLV herd profile) is 47.4% (range: 0-96.9%). A total of 3,362 cows have been sampled. Bulk tank milk samples are being evaluated as a screening tool for herd diagnosis. A similarly designed survey and longitudinal study is being conducted on beef cow-calf operations in Michigan. As of May 2016, 17 beef herds have been tested, and the average BLV prevalence is about 20% Objectives 2 & 3:Five herds were started on the field trial investigating the impact of single-use needles and gloves/sleeves on the rate of new BLV infections. Cows in the randomly-assigned intervention group are tagged so that herd managers, AI technicians, veterinarians and employees are reminded that these tagged cows should always receive a new needle and new sleeve. Compliance with the study protocol is being monitored. Each November and May, all study animals are re-tested and new additions to the milking herd are screened to identify BLV-negative animals to be randomly assigned to either the intervention group or the negative control group. Three herds with an initial BLV prevalence of approximately 50% were started on a demonstration field trial using three diagnostic tests (milk ELISA, BLV proviral load, and blood lymphocyte count) to direct culling and segregation of cattle in an effort to decrease their BLV prevalence. These additional tests should identify those cattle that are most infectious to their herdmates. Additionally, this data will be used to create a predictive model of PVL based on these other less-expensive and more widely-available indicators of BLV infection. A management tool to predict PVL based on these inputs will be made available on our website (www.blvusa.com). The rate of new infections is also being compared between the summer months and the winter months as a means of evaluating the possible impact of biting fly transmission. Three herds with initial BLV prevalence of less than 5% are participating in a demonstration project to eradicate the disease via milk ELISA testing with culling and segregation of infected cattle. At their last semi-annual test, two herds had only one BLV-positive cow detected and, except for a problem with incoming bred heifers that were raised off-site, one large herd had only two BLV-positive cows detected. Objective 4: Education: Our new BLV webpage is at www.BLVUSA.com We are in the process of moving the site to the Michigan State University server to avoid the editorial restrictions present on the MSU College of Veterinary Medicine server. Our website has been expanded to include four video lectures suitable for animal science and veterinary students as well as working dairy professionals. Additionally, we have three video presentations on single-use transrectal palpation sleeves and one presentation on single-use hypodermic needles. The website addresses the following topics: Description of the disease, BLV immunology and disease profile, tumor development, prevalence of BLV, economic impact of BLV, milk production impact, cow longevity impact, lymphoma, international trade, animal welfare issues, public health issues, BLV in beef cattle, BLV transmission, options for BLV control and control through genetic selection and vaccination. Objective 5: Extension:Our 2015 participatory research project is in its second-year follow-up. Dairy producers (n=42) paid for a BLV herd profile, which is a milk ELISA test of 40 cows (10 from each of 4 lactation groups) and completed a brief BLV risk assessment survey. They then consulted with our BLV experts and decided on management changes to reduce BLV transmission. A consultation with their herd veterinarian was also provided. This year, the participating producers are receiving a "free" repeat BLV profile with another Extension consultation to discuss their progress in controlling BLV transmission and the possible impact of their management intervention. The most common change (42% of herds) was to reduce the sharing of hypodermic needles. The data will be summarized comparing initial BLV prevalence in 2015 to final prevalence in 2016, and results will be stratified by the management changes initiated in 2015. The final summary results will be shared with all the participants and with the dairy industry in general. This year we are starting a second participatory research project which is targeted specifically to high risk herds. Our previous research has shown that herds with a low average herd age are highly likely to have a high BLV prevalence. This is due to BLV's negative impact on cow longevity. We obtained a list of DHI herds which had an extremely young average herd age (bottom 10 percentile of all DHI herds), and invited these herds to our participatory research project which is otherwise similar to the previous year's project. To date, 28 herds have been enrolled, but the enrollment period is continuing. Following this second Extension program, we will fully describe this Extension program in presentations and publication to encourage its use in other states.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2016
Citation:
Bo Norby, P. C. Bartlett,T. M. Byrem, and R. J. Erskine. Effect of infection with bovine leukemia virus on milk production in Michigan dairy cows. 2016. J. Dairy Sci. 99:110. (2015 electronic publication)
LaDronka, R.M., Norby, B., Byrem, T.M., Erskine, R.J., Grooms, D.L., & Bartlett, P.C.Descriptive epidemiology of bovine leukemia virus among herds enrolled in a national study of the impacts of infection on dairy cow longevity and production [poster presentation]. 48th Annual Conference of the American Association of Bovine Practitioners, September 18, 2015.
LaDronka, R.M., Norby, B., Byrem, T.M., Erskine, R.J., & Bartlett, P.C. Bovine leukemia virus descriptive epidemiology: Preliminary results from a national survey [oral presentation]. Phi Zeta, October 2, 2015.
LaDronka, R.M., Norby, B., Byrem, T.M., Erskine, R.J., & Bartlett, P.C. A national survey of bovine leukemia virus: Preliminary descriptive epidemiology [poster presentation]. 96th Annual Meeting of the Conference of Research Workers in Animal Diseases, December 6, 2015.
Ruggiero, V. J., Durst, P. T., Grooms, D. L., Erskine, R. J., Norby, B., LaDronka, R., Sordillo, L. M., Bartlett, P. C., Pilot extension program to control bovine leukemia virus in Michigan dairy farms. Conference of Research Workers in Animal Diseases, 2015. [Poster]
Ruggiero, V. J., Bartlett, P. C., Erskine, R. J., Norby, B., Sordillo, L. M., Field trial methodology to reduce transmission of bovine leukemia virus in Midwestern US dairy herds. Conference of Research Workers in Animal Diseases, 2015. [Poster]
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Progress 04/15/14 to 04/14/15
Outputs
Target Audience:U.S. Dairy producers, veterinarians and animal scientists Changes/Problems:In objectives 2 and 3, we had to change our plan to employ a factorial study design with four intervention groups. Tagging cattle and insuring protocol compliance with four different intervention groups proved to be unmanageable. Instead, we are using a more simple study design whereby the clearly tagged intervention group receives only new needles and sleeves. The negative control group receives shared needles and sleeves with the rest of the herd. We also added a field trial regarding the impact of frozen vs fresh colostrum on BLV transmission to calves. These changes to the protocol were approved by USDA on 6/6/14. What opportunities for training and professional development has the project provided?We have two graduate students working on BLV, and are trying to hire a 3rd graduate student or perhaps a postdoc. How have the results been disseminated to communities of interest?See objectives 4 and 5 above. See list of Extension publications and educational products. What do you plan to do during the next reporting period to accomplish the goals?(See above) We will continue and expand the field trials, complete the national survey and expand our education and Extension activities. We are on track to meet each of our objectives.
Impacts
What was accomplished under these goals?
Administration: We held a 1-day BLV meeting on December 18, 2014 to establish an External Advisory Panel and bring all our co-investigators together with our industry partners from Antelbio Systems and collaborators Drs. Aida and Takeshima from Japan. In this meeting we reviewed our previous work and the work of other BLV researchers, and we also planned our research, education and Extension plans for the years ahead. A graduate student was hired for the project. Objective 1: We began enrolling herds in this study in June of 2014. As of May 2015, 10 herds have been enrolled from each of 5 states (Michigan, Minnesota, New York, Pennsylvania, and Wisconsin). Herds were contacted and enrolled via their DHI organizations (Minnesota DHIA, North Star Wisconsin, North Star Michigan, Lancaster DHIA, and Dairy One). Management surveys were obtained, milk from 40 of their cows were tested for ELISA BLV antibodies and permission was granted for access to their DHI records. The average size of milking herds enrolled is 651 cattle, ranging from 82 to 7,453 head. We are currently working to include an additional 70 herds from 7 additional states. Objectives 2 & 3: Three herds were started on the field trial investigating the impact of single-use needles and gloves/sleeves on the rate of new BLV infections. There are 152 animals on test in the intervention group and 153 on test in the negative control group. In May 2015, all study animals were re-tested and new additions to the milking herd were screened to identify BLV-negative animals to be randomly assigned to the treatment groups. A fourth herd started the field trial in May 2015. Three herds were started on the demonstration field trial in which we use a variety of management controls to reduce herd BLV prevalence. Two more herds, starting this summer, will use BLV proviral load testing to direct culling and segregation of high proviral load cattle. This summer, one herd is starting the colostrum field trial in which newborns are randomly assigned to receive either fresh or frozen colostrum. Objective 4: Education: Our new BLV webpage is at www.BLVUSA.com We are just getting started, but Google Analytics already reports about 80 viewers per month. We have begun expanding this website to include video lectures and demonstrations of BLV control methods such as ways to quickly change reproductive examination sleeves. The video lectures will be suitable for integration into online or classroom instruction. Objective 5: Extension: Our participatory research project is going well. Dairy producers paid for a BLV herd profile, which is an ELISA test of 40 cows (10 from each of 4 lactation groups) and complete a brief BLV risk assessment survey. They then consult with our BLV experts and decide on management changes to improve BLV control. A consultation is also provided with their herd veterinarian. Participating producers then receive a "free" repeat BLV profile about one year later with another Extension consultation to discuss their progress in controlling BLV transmission. So far there have been 49 herds enrolled from 24 veterinary practices. To date, 35 herds have received their first BLV profile.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Paul C. Bartlett, Ronald J. Erskine, Lorraine Sordillo, Todd Byrem, Bo Norby, Daniel Grooms, Jessica Zalucha. Options for the Control of Bovine Leukemia Virus in U.S. Dairy Cattle. J. Am. Vet. Med. Assoc. JAVMA, Vol 244, No. 8, April 15, 2014
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