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Shrestha S, Orsel K, Droscha C, Mijar S, van der Meer F. Removing bovine leukemia virus infected animals with high proviral load leads to lowering within-herd prevalence and new case reduction. J Dairy Sci 2024:S0022-0302(24)00633-7. [PMID: 38554820 DOI: 10.3168/jds.2023-24484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 02/22/2024] [Indexed: 04/02/2024]
Abstract
Bovine leukosis is prevalent in the North American dairy industry and its effect on animal health and production is widely documented. However, not all bovine leukemia virus (BLV) infected animals transmit the virus equally. Animals with high BLV proviral loads (HPL) are associated with higher transmission risks and therefore, their removal may reduce transmission and eventually within-herd prevalence. We aimed to evaluate the impact of selectively removing HPL cows on the within-herd BLV prevalence and incidence rate of BLV infection in 10 dairy herds. Annual blood and/or milk samples were collected from adult cows over 3 years. Positivity with BLV were determined by ELISA tests and proviral loads in blood of BLV-positive animals were estimated with BLV SS1 quantitative PCR assays. Herd managers were encouraged to consider the proviral load when making culling decisions and implement BLV control practices. High proviral load cows had the highest relative risk of removal indicating the farmers prioritized HPL cows for culling. The within-herd BLV prevalence decreased significantly in 4 herds whereas BLV incidence rate decreased in 9 herds. Over the 3 years, the proviral load demonstrated a relatively stable level, suggesting a single proviral load test in an adult cow may suffice to make culling decisions.
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Affiliation(s)
- Sulav Shrestha
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada T2N 4N1.
| | - Karin Orsel
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada T2N 4N1
| | - Casey Droscha
- CentralStar Cooperative, Inc., East Lansing, Michigan, USA
| | - Sanjaya Mijar
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada T2N 4N1
| | - Frank van der Meer
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada T2N 4N1
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Shrestha S, Orsel K, Barkema HW, Martins L, Shrestha S, van der Meer F. Effects of bovine leukemia virus seropositivity and proviral load on milk, fat, and protein production of dairy cows. J Dairy Sci 2024; 107:530-539. [PMID: 37709045 DOI: 10.3168/jds.2023-23695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 08/22/2023] [Indexed: 09/16/2023]
Abstract
The objective was to evaluate the effects of bovine leukemia virus (BLV) infection, as determined by BLV seropositivity and proviral load, on 305-d milk, fat, and protein production of dairy cows. A cross-sectional study was conducted among 1,712 cows from 9 dairy herds in Alberta, Canada. The BLV status was assessed using an antibody ELISA, whereas BLV proviral load in BLV-seropositive cattle was determined with quantitative PCR. Dairy Herd Improvement 305-d milk, fat, and protein production data were obtained for all enrolled cattle. Differences in these milk end points were assessed in 2 ways: first, by categorizing cows based on BLV serostatus (i.e., BLV positive or negative), and second, by categorizing based on BLV proviral load (i.e., BLV negative, low proviral load [LPL] BLV positive, and high proviral load [HPL] BLV positive). A mixed-effect multivariable linear regression model was used to assess differences in milk parameters. We found that BLV positivity, adjusted for parity and natural log-transformed somatic cell count (SCC), was not associated with reduction in 305-d milk, fat, or protein production. However, significant reductions in 305-d milk, fat, and protein yield occurred in HPL cows, but not in LPL cows, compared with BLV-negative cows, when adjusted for parity number and natural log-transformed SCC. In summary, BLV proviral load may predict effects of BLV infection on milk, fat, and protein production.
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Affiliation(s)
- Sulav Shrestha
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada T2N 4N1.
| | - Karin Orsel
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada T2N 4N1
| | - Herman W Barkema
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada T2N 4N1; Cumming School of Medicine, University of Calgary, Calgary, AB, Canada T2N 4N1
| | - Larissa Martins
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada T2N 4N1
| | - Samita Shrestha
- Cumming School of Medicine, University of Calgary, Calgary, AB, Canada T2N 4N1
| | - Frank van der Meer
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada T2N 4N1
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Marawan MA, Alouffi A, El Tokhy S, Badawy S, Shirani I, Dawood A, Guo A, Almutairi MM, Alshammari FA, Selim A. Bovine Leukaemia Virus: Current Epidemiological Circumstance and Future Prospective. Viruses 2021; 13:v13112167. [PMID: 34834973 PMCID: PMC8618541 DOI: 10.3390/v13112167] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Revised: 10/23/2021] [Accepted: 10/24/2021] [Indexed: 11/23/2022] Open
Abstract
Bovine leukaemia virus (BLV) is a deltaretrovirus that is closely related to human T-cell leukaemia virus types 1 and 2 (HTLV-1 and -2). It causes enzootic bovine leukosis (EBL), which is the most important neoplastic disease in cattle. Most BLV-infected cattle are asymptomatic, which potentiates extremely high shedding rates of the virus in many cattle populations. Approximately 30% of them show persistent lymphocytosis that has various clinical outcomes; only a small proportion of animals (less than 5%) exhibit signs of EBL. BLV causes major economic losses in the cattle industry, especially in dairy farms. Direct costs are due to a decrease in animal productivity and in cow longevity; indirect costs are caused by restrictions that are placed on the import of animals and animal products from infected areas. Most European regions have implemented an efficient eradication programme, yet BLV prevalence remains high worldwide. Control of the disease is not feasible because there is no effective vaccine against it. Therefore, detection and early diagnosis of the disease are essential in order to diminish its spreading and the economic losses it causes. This review comprises an overview of bovine leukosis, which highlights the epidemiology of the disease, diagnostic tests that are used and effective control strategies.
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Affiliation(s)
- Marawan A. Marawan
- The State Key Laboratory of Agricultural Microbiology, Huazhong Agriculture University, Wuhan 430070, China; (I.S.); (A.D.)
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
- Department of Animal Medicine (Infectious Diseases), Faculty of Veterinary Medicine, Benha University, Toukh 13736, Egypt;
- Correspondence: (M.A.M.); (A.G.); (A.S.)
| | - Abdulaziz Alouffi
- King Abdulaziz City for Science and Technology, Riyadh 12354, Saudi Arabia;
- The Chair of Vaccines Research for Infectious Diseases, King Saud University, Riyadh 11495, Saudi Arabia;
| | - Suleiman El Tokhy
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Tanta University, Tanta 31111, Egypt;
| | - Sara Badawy
- Department of Pathology, Faculty of Veterinary Medicine, Benha University, Toukh 13736, Egypt;
- Natural Reference Laboratory of Veterinary Drug Residues (HZAU), MAO Key Laboratory for Detection of Veterinary Drug Residues Huazhong Agricultural University, Wuhan 430070, China
| | - Ihsanullah Shirani
- The State Key Laboratory of Agricultural Microbiology, Huazhong Agriculture University, Wuhan 430070, China; (I.S.); (A.D.)
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
- Para-Clinic Department, Faculty of Veterinary Medicine, Jalalabad 2601, Afghanistan
| | - Ali Dawood
- The State Key Laboratory of Agricultural Microbiology, Huazhong Agriculture University, Wuhan 430070, China; (I.S.); (A.D.)
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
- Infectious Diseases, Medicine Department, Faculty of Veterinary Medicine, University of Sadat City, Sadat City 32897, Egypt
| | - Aizhen Guo
- The State Key Laboratory of Agricultural Microbiology, Huazhong Agriculture University, Wuhan 430070, China; (I.S.); (A.D.)
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
- Hubei International Scientific and Technological Cooperation Base of Veterinary Epidemiology, Huazhong Agricultural University, Wuhan 430070, China
- Correspondence: (M.A.M.); (A.G.); (A.S.)
| | - Mashal M. Almutairi
- The Chair of Vaccines Research for Infectious Diseases, King Saud University, Riyadh 11495, Saudi Arabia;
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh 22334, Saudi Arabia
| | - Fahdah Ayed Alshammari
- College of Sciences and Literature Microbiology, Nothern Border University, Arar 73211, Saudi Arabia;
| | - Abdelfattah Selim
- Department of Animal Medicine (Infectious Diseases), Faculty of Veterinary Medicine, Benha University, Toukh 13736, Egypt;
- Correspondence: (M.A.M.); (A.G.); (A.S.)
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Abdalla EA, Weigel KA, Byrem TM, Rosa GJM. Short communication: Genetic correlation of bovine leukosis incidence with somatic cell score and milk yield in a US Holstein population. J Dairy Sci 2016; 99:2005-2009. [PMID: 26778307 DOI: 10.3168/jds.2015-9833] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 11/11/2015] [Indexed: 11/19/2022]
Abstract
Bovine leukosis (BL) is a retroviral disease caused by the bovine leukosis virus (BLV), which affects only cattle. Dairy cows positive for BL produce less milk and have more days open than cows negative for BL. In addition, the virus also affects the immune system and causes weaker response to vaccines. Heritability estimates of BL incidence have been reported for Jersey and Holstein populations at about 0.08, indicating an important genetic component that can potentially be exploited to reduce the prevalence of the disease. However, before BL is used in selection programs, it is important to study its genetic associations with other economically important traits such that correlated responses to selection can be predicted. Hence, this study aimed to estimate the genetic correlations of BL with milk yield (MY) and with somatic cell score (SCS). Data of a commercial assay (ELISA) used to detect BLV antibodies in milk samples were obtained from Antel BioSystems (Lansing, MI). The data included continuous milk ELISA scores and binary milk ELISA results for 11,554 cows from 112 dairy herds across 16 US states. Continuous and binary milk ELISA were analyzed with linear and threshold models, respectively, together with MY and SCS using multitrait animal models. Genetic correlations (posterior means ± standard deviations) between BL incidence and MY were 0.17 ± 0.077 and 0.14 ± 0.076 using ELISA scores and results, respectively; with SCS, such estimates were 0.20 ± 0.081 and 0.17 ± 0.079, respectively. In summary, the results indicate that selection for higher MY may lead to increased BLV prevalence in dairy herds, but that the inclusion of BL (or SCS as an indicator trait) in selection indexes may help attenuate this problem.
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Affiliation(s)
- E A Abdalla
- Department of Animal Sciences, University of Wisconsin, Madison 53706; Department of Animal Science, University of Benghazi, Benghazi, Libya 21861.
| | - K A Weigel
- Department of Dairy Science, University of Wisconsin, Madison 53706
| | - T M Byrem
- Antel BioSystems Inc., Lansing, MI 48910
| | - G J M Rosa
- Department of Animal Sciences, University of Wisconsin, Madison 53706; Department of Biostatistics and Medical Informatics, University of Wisconsin, Madison 53706
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Onuma M, Yasutomi Y, Okada HM, Matsukawa K, Yoshikawa H, Yoshikawa T, Okada K, Takahashi K, Kirisawa R, Kawakami Y. The screening of cattle with potential for developing leukemia by using monoclonal antibody against bovine leukemia cells. Jpn J Cancer Res 1988; 79:275-81. [PMID: 2896664 PMCID: PMC5917467 DOI: 10.1111/j.1349-7006.1988.tb01587.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Tumor cells from cattle with enzootic bovine lymphosarcoma (EBL) have a tumor-associated antigen (TAA) which is distinct from bovine leukemia virus (BLV)-induced antigens. We were able to sacrifice 8 TAA-positive cattle with no clinical signs of EBL and to examine whether or not they had gross or histological tumors. At necropsy, 4 animals had tumors macroscopically. Three animals had no tumors histologically but had initial lesions showing follicular hyperplasia and had the TAA on affected lymph nodes. The remaining one showed medullary hyperplasia in the spleen but there were no findings of tumors. These results suggest that most BLV-infected cattle which are TAA-positive but have no clinical signs of EBL, do have tumors and have a higher potential for developing EBL in the future when compared to BLV-infected but TAA-negative cattle.
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Affiliation(s)
- M Onuma
- Department of Veterinary Microbiology, Rakuno Gakuen University, Ebetsu
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Kvarnfors E, Henricson B, Hugoson G. A statistical study on farm and village level on the possible relations between human leukaemia and bovine leukosis. Acta Vet Scand 1975; 16:163-9. [PMID: 1242289 PMCID: PMC8396084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/1974] [Indexed: 12/26/2022] Open
Abstract
In order to further elucidate a possible relationship between bovine leukosis and human leukaemia a comparative statistical study on herd and village level was performed for an 11 year period in a Swedish county where bovine leukosis incidence as well as human leukaemia mortality were above the national mean. The addresses of the human leukaemia cases and bovine leukosis cases were traced. As control material were used farms and villages situated within 5 ± 0.1 km from each human case address. The difference between the addresses of human leukaemia cases and the control addresses with respect to the occurrence of bovine leukosis was not found to be statistically significant. There was no statistically significant difference in frequency between human cases with professions associated and not associated with farming with respect to the occurrence of bovine leukosis on the same addresses. A comparison between the frequency of addresses for human leukaemia and controls with respect to the occurrence of cattle on the addresses did not give statistically significant higher values for those human leukaemia addresses having housed cattle. A study of the time elapse between each human case and the bovine case(s) on the same address did not indicate a regular appearance earlier or later of the bovine case. The possibilities to evaluate with reliability a material of this kind are discussed.
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