Establishment of a bovine leukemia virus-free dairy herd in Korea

Suh, Guk Hyun; Lee, Jeong Chi; Lee, Chai Yong; Hur, Tai Young; Son, Dong-Soo; Ahn, Byungchan; Kim, Nam Chul; Lee, Chung Gil

doi:10.4142/jvs.2005.6.3.227

Cited by 21 publications

(17 citation statements)

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“…Additionally, calves born infected should be identified as soon as possible and segregated from the herd. Some of these management practices are included in control programmes based on “test and segregate,” and have been useful to decrease prevalence or even achieve eradication of the disease ( 33 , 47 , 71 ).…”

Section: Preventive Strategies During Parturitionmentioning

confidence: 99%

Bovine Leukemia Virus Infection in Neonatal Calves. Risk Factors and Control Measures

et al. 2018

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Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leukosis (EBL). Although efficient eradication programs have been successfully implemented in most European countries and Oceania, BLV infection rates are still high worldwide. BLV naturally infects cattle, inducing a persistent infection with diverse clinical outcomes. The virus infects lymphocytes and integrates a DNA intermediate as a provirus into the genome of the cells. Therefore, exposure to biological fluids contaminated with infected lymphocytes potentially spreads the virus. Vertical transmission may occur in utero or during delivery, and about 10% of calves born to BLV-infected dams are already infected at birth. Most frequently, transmission from dams to their offspring occurs through the ingestion of infected colostrum or milk. Therefore, although EBL is not a disease specific to the neonatal period, during this period the calves are at special risk of becoming infected, especially in dairy farms, where they ingest colostrum and/or raw milk either naturally or artificially. Calves infected during the first week of life could play an active role in early propagation of BLV to susceptible animals. This review discusses the main factors that contribute to neonatal BLV infection in dairy herds, as well as different approaches and management practices that could be implemented to reduce the risk of BLV transmission during this period, aiming to decrease BLV infection in dairy herds.

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Section: Preventive Strategies During Parturitionmentioning

confidence: 99%

Bovine Leukemia Virus Infection in Neonatal Calves. Risk Factors and Control Measures

et al. 2018

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“…The seroprevalence rates in Japan were found to be 28.6% and 68.1% at the individual and herd levels, respectively [70]. In Korea, individual seroprevalence rates exceeded 50% whilst 86.8% of dairy herds were infected [71]. …”

Section: Epidemiologymentioning

confidence: 99%

Preventive and Therapeutic Strategies for Bovine Leukemia Virus: Lessons for HTLV

Rodríguez

Florins

Gillet

et al. 2011

Viruses

176

126

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Bovine leukemia virus (BLV) is a retrovirus closely related to the human T-lymphotropic virus type 1 (HTLV-1). BLV is a major animal health problem worldwide causing important economic losses. A series of attempts were developed to reduce prevalence, chiefly by eradication of infected cattle, segregation of BLV-free animals and vaccination. Although having been instrumental in regions such as the EU, these strategies were unsuccessful elsewhere mainly due to economic costs, management restrictions and lack of an efficient vaccine. This review, which summarizes the different attempts previously developed to decrease seroprevalence of BLV, may be informative for management of HTLV-1 infection. We also propose a new approach based on competitive infection with virus deletants aiming at reducing proviral loads.

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“…This was expected and can be explained by the highest rate of yearly reduction in prevalence, resulting in the highest net benefit, compared with other strategies. According to available literature (Johnson et al, 1985;Suh et al, 2005), test-and-segregate control programs are highly efficient in preventing new infections, therefore resulting in a rapid increase in income. Although this strategy requires structural and organizational changes for dairy operations that might be difficult to implement, it offers an effective way of preventing new infections when uninfected replacement animals are difficult to realize.…”

Section: Discussionmentioning

confidence: 99%

Economic evaluation of 4 bovine leukemia virus control strategies for Alberta dairy farms

Kuczewski

Hogeveen

Orsel

et al. 2019

Journal of Dairy Science

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Bovine leukemia virus (BLV) is a production-limiting disease common in North American dairy herds. To make evidence-based recommendations to Canadian dairy producers and their consultants regarding cost and financial benefits of BLV on-farm control, an economic model that takes the supply-managed milk quota system into account is necessary. Albertaspecific input variables were used for the presented analysis. A decision tree model program was used to evaluate economic aspects of decreasing a 40% BLV within-herd prevalence on dairy farms by implementing various control strategies over 10 yr. Investigated strategies were (1) all management strategies, including 3 options for colostrum management; (2) some management strategies; (3) test and cull; and (4) test and segregate. Each of these strategies was compared with a no control on-farm approach. The prevalence for this no-control approach was assumed to stay constant over time. Each control strategy incurred specific yearly cost and yielded yearly decreases in prevalence, thereby affecting yearly partial net revenue. Infection with BLV was assumed to decrease milk production, decrease cow longevity, and increase condemnation of carcasses at slaughter from cattle with enzootic bovine leukosis, thereby decreasing net revenue. Cows infected with BLV generated a yearly mean partial net revenue of Can$7,641, whereas noninfected cows generated Can$8,276. Mean cost for the control strategies ranged from Can$193 to Can$847 per animal over 10 yr in a 146-animal herd. Net benefits of controlling BLV on farm, as compared with not controlling BLV, per cow in a 146-animal herd over a 10-yr period for each strategy was: Can$1,315 for all management strategies (freezer); Can$1,243 for all management strategies (pasteurizer); Can$785 for all management strategies (powdered colostrum); Can$1,028 for some management strategies; Can$1,592 for test and cull; and Can$1,594 for test and segregate. Consequently, on-farm BLV control was financially beneficial. Even though negative net benefits were possible and expected for some iterations, our sensitivity analysis highlighted the overall robustness of our model. In summary, this model provided evidence that Canadian dairy farmers should be encouraged to control BLV on their farm.

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Establishment of a bovine leukemia virus-free dairy herd in Korea

Cited by 21 publications

References 0 publications

Bovine Leukemia Virus Infection in Neonatal Calves. Risk Factors and Control Measures

Bovine Leukemia Virus Infection in Neonatal Calves. Risk Factors and Control Measures

Preventive and Therapeutic Strategies for Bovine Leukemia Virus: Lessons for HTLV

Economic evaluation of 4 bovine leukemia virus control strategies for Alberta dairy farms

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