Economic implications of bovine leukemia virus infection in mid-Atlantic dairy herds

Rhodes, J. Kelly; Pelzer, Kevin D.; Johnson, Yvette J.

doi:10.2460/javma.2003.223.346

Cited by 53 publications

(47 citation statements)

References 18 publications

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“…It has been demonstrated that there are management factors positively associated with within-herd BLV prevalence and decreased cow longevity (Bartlett et al, 2014). Although lymphosarcoma is the most obvious negative outcome of BLV infection and can certainly adversely influence mortality rates (Olson, 1974), less than 5% of infected cattle typically show clinical signs of lymphosarcoma (Rhodes et al, 2003). In most cases it is expected that the longevity of BLV-infected animals is decreased due to compromised immune function and susceptibility of infected animals to multiple opportunistic pathogens (Bartlett et al, 2014).…”

Section: Discussionmentioning

confidence: 99%

Herd factors associated with dairy cow mortality

McConnel

Lombard

Wagner

et al. 2015

Animal

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Summary studies of dairy cow removal indicate increasing levels of mortality over the past several decades. This poses a serious problem for the US dairy industry. The objective of this project was to evaluate associations between facilities, herd management practices, disease occurrence and death rates on US dairy operations through an analysis of the National Animal Health Monitoring System's Dairy 2007 survey. The survey included farms in 17 states that represented 79.5% of US dairy operations and 82.5% of the US dairy cow population. During the first phase of the study operations were randomly selected from a sampling list maintained by the National Agricultural Statistics Service. Only farms that participated in phase I and had 30 or more dairy cows were eligible to participate in phase II. In total, 459 farms had complete data for all selected variables and were included in this analysis. Univariable associations between dairy cow mortality and 162 a priori identified operation-level management practices or characteristics were evaluated. Sixty of the 162 management factors explored in the univariate analysis met initial screening criteria and were further evaluated in a multivariable model exploring more complex relationships. The final weighted, negative binomial regression model included six variables. Based on the incidence rate ratio, this model predicted 32.0% less mortality for operations that vaccinated heifers for at least one of the following: bovine viral diarrhea, infectious bovine rhinotracheitis, parainfluenza 3, bovine respiratory syncytial virus, Haemophilus somnus, leptospirosis, Salmonella, Escherichia coli or clostridia. The final multivariable model also predicted a 27.0% increase in mortality for operations from which a bulk tank milk sample tested ELISA positive for bovine leukosis virus. Additionally, an 18.0% higher mortality was predicted for operations that used necropsies to determine the cause of death for some proportion of dead dairy cows. The final model also predicted that increased proportions of dairy cows with clinical mastitis and infertility problems were associated with increased mortality. Finally, an increase in mortality was predicted to be associated with an increase in the proportion of lame or injured permanently removed dairy cows. In general terms, this model identified that mortality was associated with reproductive problems, non-infectious postpartum disease, infectious disease and infectious disease prevention, and information derived from postmortem evaluations. Ultimately, addressing excessive mortality levels requires a concerted effort that recognizes and appropriately manages the numerous and diverse underlying risks.

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Section: Discussionmentioning

confidence: 99%

Herd factors associated with dairy cow mortality

McConnel

Lombard

Wagner

et al. 2015

Animal

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“…In dairy farms with low prevalence of BLV infection, the cost of implementing these programs is less than the total cost caused by BLV infection [111]. However, in herds where the prevalence of infection is high, the feasibility of implementation of these programs depends on the official compensation to producers for the removal of BLV-positive animals.…”

Section: Strategies To Control Blv Infectionmentioning

confidence: 99%

Major Histocompatibility Complex-Associated Resistance to Infectious Diseases: The Case of Bovine Leukemia Virus Infection

Gutiérrez¹,

Esteban²,

Lützelschwab³

et al. 2017

Trends and Advances in Veterinary Genetics

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The major histocompatibility complex (MHC) is a polymorphic gene cluster of about 150 genes, present in all vertebrates. Many of these genes contribute to immunity. Particularly, MHC-encoded class I and class II molecules, which are typically highly polymorphic and polygenic, are central in defining the specificity of the adaptive immune response. Among the diversity of genes associated with disease resistance, MHC genes are particularly interesting as they are associated with resistance and susceptibility to a wide range of diseases, some of which produce important economic losses in livestock. Enzootic bovine leukosis is an infectious disease caused by the retrovirus bovine leukemia virus (BLV), with an important economic impact, mainly in dairy herds. In this chapter, MHC-associated genetic resistance to BLV is revised. Certain alleles of the bovine MHC (BoLA) class II locus have been found strongly associated with resistance to viral dissemination. Genetic selection of resistant animals emerges as a natural strategy for the control of infectious diseases, especially when there is no other alternative of control or prevention, as vaccines. Founded on this knowledge, a BLV control program based on selection of genetically resistant cattle was designed. The proof of concept indicates that this strategy is feasible to implement in dairy herds.

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“…On herd level, the estimated mean cost to the producer per lymphoma case was 412 dollars and the mean annual cost of subclinical infection at a 50% prevalence of infection was 6,406 dollars per 100 milking cows in 2003 (Rhodes et al, 2003).…”

Section: Article 7(d)(vii) Disposal Of Carcasses and Other Relevant Amentioning

confidence: 99%

Assessment of listing and categorisation of animal diseases within the framework of the Animal Health Law (Regulation (EU) No 2016/429): enzootic bovine leukosis (EBL)

More¹,

Bøtner²,

Butterworth

et al. 2017

EFS2

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Enzootic bovine leucosis (EBL) has been assessed according to the criteria of the Animal Health Law (AHL), in particular criteria of Article 7 on disease profile and impacts, Article 5 on the eligibility of EBL to be listed, Article 9 for the categorisation of EBL according to disease prevention and control rules as in Annex IV and Article 8 on the list of animal species related to EBL. The assessment has been performed following a methodology composed of information collection and compilation, expert judgement on each criterion at individual and, if no consensus was reached before, also at collective level. The output is composed of the categorical answer, and for the questions where no consensus was reached, the different supporting views are reported. Details on the methodology used for this assessment are explained in a separate opinion. According to the assessment performed, it is inconclusive whether EBL can be considered eligible to be listed for Union intervention as laid down in Article 5(3) of the AHL because there was no full consensus on the criteria 5 B(i) and 5 B(iii). Consequently, since it is inconclusive whether EBL can be considered eligible to be listed for Union intervention as laid down in Article 5(3) of the AHL, then the assessment on compliance of EBL with the criteria as in Sections 4 and 5 of Annex IV to the AHL, for the application of the disease prevention and control rules referred to in points (d) and (e) of Article 9(1), and which animal species can be considered to be listed for EBL according to Article 8(3) of the AHL is also inconclusive.

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Economic implications of bovine leukemia virus infection in mid-Atlantic dairy herds

Abstract: Results suggested that a basic BLV control program may be economically beneficial in herds in which the prevalence of BLV infection is > or = 12.5%. Farm-specific considerations may factor prominently when weighing the costs and benefits of an individual BLV control program.

Cited by 53 publications

References 18 publications

Herd factors associated with dairy cow mortality

Herd factors associated with dairy cow mortality

Major Histocompatibility Complex-Associated Resistance to Infectious Diseases: The Case of Bovine Leukemia Virus Infection

Assessment of listing and categorisation of animal diseases within the framework of the Animal Health Law (Regulation (EU) No 2016/429): enzootic bovine leukosis (EBL)

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