Predicting within-herd prevalence of infection with bovine leukemia virus using bulk-tank milk antibody levels

Nekouei, Omid; Stryhn, Henrik; VanLeeuwen, John A.; Kelton, D.F.; Hanna, Paul E.; Keefe, Greg

doi:10.1016/j.prevetmed.2015.10.009

Cited by 28 publications

(23 citation statements)

References 24 publications

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“…The BCV ELISA cut-off was fixed at sample positive > 10 PP for all alternatives. likely affect the number of antibody producing animals needed for a positive BTM result, and a positive correlation between within-herd prevalence and OD-value has been shown for other diseases (Muskens et al, 2011;Nekouei et al, 2015). Because the typical Norwegian dairy herd is small (mean herd size 25.7) (Anon., 2015) compared to most other developed countries, this might influence the generalizability of our results: In larger herds antibodies might be diluted in the bulk tank, and hence cause the test Se to decrease.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of a multiplex immunoassay for bovine respiratory syncytial virus and bovine coronavirus antibodies in bulk tank milk against two indirect ELISAs using latent class analysis

Toftaker

Toft

Stokstad

et al. 2018

Preventive Veterinary Medicine

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Bovine respiratory syncytial virus (BRSV) and bovine coronavirus (BCV) are responsible for respiratory disease and diarrhea in cattle worldwide. The Norwegian control program against these infections is based on herd-level diagnosis using a new multiplex immunoassay. The objective of this study was to estimate sensitivity and specificity across different cut-off values for the MVD-Enferplex BCV/BRSV multiplex, by comparing them to a commercially available ELISA, the SVANOVIR BCV-Ab and SVANOVIR BRSV-Ab, respectively. We analyzed bulk tank milk samples from 360 herds in a low- and 360 herds in a high-prevalence area. As none of the tests were considered perfect, estimation of test characteristics was performed using Bayesian latent class models. At the manufacturers' recommended cut-off values, the median sensitivity for the BRSV multiplex and the BRSV ELISA was 94.4 [89.8-98.7 95% Posterior Credibility Interval (PCI)] and 99.8 [98.7-100 95% PCI], respectively. The median specificity for the BRSV multiplex was 90.6 [85.5-94.4 95% PCI], but only 57.4 [50.5-64.4 95% PCI] for the BRSV ELISA. However, increasing the cut-off of the BRSV ELISA increased specificity without compromising sensitivity. For the BCV multiplex we found that by using only one of the three antigens included in the test, the specificity increased, without concurrent loss in sensitivity. At the recommended cut-off this resulted in a sensitivity of 99.9 [99.3-100 95% PCI] and specificity of 93.7 [88.8-97.8 95% PCI] for the multiplex and a sensitivity of 99.5 [98.1-100 95% PCI] and a specificity of 99.6 [97.6-100 95% PCI] for the BCV ELISA.

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Section: Discussionmentioning

confidence: 99%

Evaluation of a multiplex immunoassay for bovine respiratory syncytial virus and bovine coronavirus antibodies in bulk tank milk against two indirect ELISAs using latent class analysis

Toftaker

Toft

Stokstad

et al. 2018

Preventive Veterinary Medicine

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“…In many other regions of the world, however, the disease is widespread. For example, in the maritime region of Canada, the herd-level prevalence of BLV was 90.8% based on bulk tank milk census (Nekouei et al, 2015) and 84% of dairy herds in the United States were reported positive in 2007 (USDA, 2008). In South America, the individual prevalence rate in dairy cows is reported to be approximately 33 to 50%, with herd-level prevalence in dairy cows over 84% (Trono et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Bovine leukemia virus infection in cattle of China: Association with reduced milk production and increased somatic cell score

Yang

Fan

Mao

et al. 2016

Journal of Dairy Science

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The main objective of this study was to investigate the individual cow effect of bovine leukemia virus (BLV) infection on milk production and somatic cell score (SCS). The fluorescence resonance energy transfer (FRET) quantitative PCR established in this study and a commercial ELISA kit revealed that 49.1% of dairy cattle (964/1,963) from 6 provinces of China and 1.6% of beef cattle (22/1,390) from 15 provinces were BLV positive. In a detailed study of 105 cows, BLV was found most commonly in buffy coat samples that also had highest copy numbers (10(4.75±1.56) per mL); all cows negative for BLV in buffy coat samples were also negative in vaginal swab, milk, and fecal samples. Copy numbers of BLV were 10(2.90±0.42)/gram of feces, 10(0.83±0.62)/mL of milk, and 10(2.18±0.81) per vaginal swab. The BLV-positive cows had significantly lower milk production in the early (26.8 vs. 30.9kg) and middle stages of lactation (22.2 vs. 26.1kg) in animals with ≥4 parities than the BLV-negative cows; they also had significantly higher SCS in early and middle lactation stages (early=5.2 vs. 4.3; middle=4.9 vs. 3.9) in animals with ≥4 parities. Milk production and SCS did not significantly differ between the BLV-infected and -uninfected cows when they were in the late lactation stage or in animals with ≤3 parities. Taken together, our results indicate that BLV infections are widespread in the dairy farms of China. Vaginal secretions and feces may be involved in BLV transmission. A BLV infection may result in reduced milk yield and increased SCS in a parity and lactation stage-restricted manner.

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“…The stakeholder workshop emphasised the need for the pilot study to address the longstanding governance challenges in agricultural and veterinary service delivery [23,24]. The joint service should not be seen to compete with private veterinary practices, where they exist, and must comply with the Veterinary Surgeons Act (1958).…”

Section: Towards More Integration Of Health Servicesmentioning

confidence: 99%

“…The joint service should not be seen to compete with private veterinary practices, where they exist, and must comply with the Veterinary Surgeons Act (1958). Recent studies highlight the considerable potential of enhancing the quality and coverage of animal health services by strengthened co-operation between veterinarians and para-professionals [20,23] and provide valuable guidance for further evaluation.…”

Section: Towards More Integration Of Health Servicesmentioning

confidence: 99%

Reaching for the low hanging fruits: One health benefits of joint crop–livestock services for small-scale farmers

Danielsen¹,

Kajura

Mulema

et al. 2019

One Health

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The benefits of joint health service delivery remain under-explored in One Health. Plant clinics are known to provide ad hoc, undocumented advice on animal health and production to farmers. To understand the scope of this activity, 180 plant doctors (extension workers) in Uganda, Kenya, Zambia, Peru and Costa Rica were surveyed and a workshop involving key stakeholders was organized in Uganda. Most (81%) plant doctors regularly received queries from farmers on livestock topics. This shows that the single sectoral approach to service delivery often does not match small-scale farmers' needs. There is growing interest among service providers, ministry officials and researchers to improve integration of farmer services to reduce operational costs and make better use of existing capacities. The workshop supported the proposal for the first ‘crop-livestock clinics’ to be trialled and evaluated in Uganda. This will inform other countries on the potential of joint services to mixed crop-livestock farming communities.

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Predicting within-herd prevalence of infection with bovine leukemia virus using bulk-tank milk antibody levels

Cited by 28 publications

References 24 publications

Evaluation of a multiplex immunoassay for bovine respiratory syncytial virus and bovine coronavirus antibodies in bulk tank milk against two indirect ELISAs using latent class analysis

Evaluation of a multiplex immunoassay for bovine respiratory syncytial virus and bovine coronavirus antibodies in bulk tank milk against two indirect ELISAs using latent class analysis

Bovine leukemia virus infection in cattle of China: Association with reduced milk production and increased somatic cell score

Reaching for the low hanging fruits: One health benefits of joint crop–livestock services for small-scale farmers

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