1,720,969 research outputs found
A NEW TECHNOLOGY FOR MEASURING THE EFFECT OF GASTROINTESTINAL NEMATODES IN LACTATING CATTLE
No full textKeefe, Greg. (2002). A NEW TECHNOLOGY FOR MEASURING THE EFFECT OF GASTROINTESTINAL NEMATODES IN LACTATING CATTLE. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/108763
WHY YOU SHOULDN'T HAVE SLEPT THROUGH PARASITOLOGY - IMPACTS ON MILK PRODUCTION
No full textKeefe, Greg. (2002). WHY YOU SHOULDN'T HAVE SLEPT THROUGH PARASITOLOGY - IMPACTS ON MILK PRODUCTION. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/108762
Systematic review: what is the best antibiotic treatment for Staphylococcus aureus intramammary infection of lactating cows in North America?
No full textStaphylococcus aureus is the most prevalent pathogen causing intramammary infections (IMI) in dairy cattle worldwide. New treatment regimens have been evaluated to increase cure rates. A systematic review was conducted to answer this question: what is the best antibiotic treatment for S aureus IMI of lactating cows in North America? Direct comparison between studies (n = 6) was difficult since there was no clinical trial comparing all antibiotics and large variations between study protocols and enrolment and outcome definitions were observed. The best therapeutic option currently available in North America is an extended intramammary therapy for 5 to 8 days.;Source type: Electronic(1
Diagnostic performance of an indirect enzyme-linked immunosorbent assay (ELISA) to detect bovine leukemia virus antibodies in bulk-tank milk samples.
No full textThis study assessed the diagnostic performance of a commercial ELISA for detecting bovine leukemia virus antibodies in bulk-tank milk samples from eastern Canada. Sensitivity and specificity of the test were estimated at 97.2% and 100%, respectively. The test was recommended as a cost-efficient tool for large-scale screening programs.journal article2016 Julimporte
Evaluation of quarter-based selective dry cow therapy using Petrifilm on-farm milk culture: A randomized controlled trial
No full textThe objective of this randomized controlled trial was
to assess the efficacy of an on-farm culture system using Petrifilm (3M, London, ON, Canada) for targeted
treatment decisions at the quarter level at dry-off and
its effects on dry period intramammary infections (IMI)
and udder health and milk production in the subsequent lactation. A total of 568 cows (2,247 quarters)
from 9 dairy herds with bulk tank somatic cell count
<250,000 cells/mL in Québec, Canada, were systematically enrolled and randomly allocated to 4 groups: 2
quarter-based selective (QSDCT) groups, using results
of quarter-milk culture on Petrifilm, and 2 blanket dry
cow therapy (BDCT) groups. The 2 QSDCT groups
consisted of (1) antimicrobial to infected quarters and
internal teat sealant (ITS) to healthy quarters (QSDCT/ITS); and (2) antimicrobial and ITS to infected
quarters and ITS to healthy quarters (QSDCT+ITS/
ITS). The 2 BDCT groups were (1) antimicrobial alone
to all quarters (BDCT); and (2) antimicrobial and ITS
to all quarters (BDCT+ITS). Quarter milk samples
were collected at dry-off and after calving for routine
bacteriological culture at the laboratory to monitor
IMI; data on milk production, somatic cell count, and
clinical mastitis recorded up to 120 d in milk were retrieved from health and DHI records. The probability
of avoiding antimicrobial treatment in QSDCT groups
was estimated at 48.3% (95% confidence interval: 35.7,
60.9). There was no significant difference between the
4 treatment groups regarding acquisition of new IMI
(15.9, 13.2, 15.8, and 15.1% probability for BDCT,
BDCT+ITS, QSDCT/ITS, and QSDCT+ITS/ITS,
respectively) or persistence of existing IMI (3.2, 2.1,
3.4, and 2.7% probability, respectively) over the dry
period. In the subsequent lactation, there was no difference between groups regarding incidence of clinical
mastitis (2.4, 3.7, 2.9, and 1.7% respectively for BDCT,
BDCT+ITS, QSDCT/ITS, and QSDCT+ITS/ITS),
mean milk somatic cell score (1.7, 2.0, 2.0, and 2.0 respectively), or mean daily milk production (43.8, 44.2,
43.2, and 42.6 kg/d, respectively) during the first 120
d in milk. In conclusion, QSDCT using the Petrifilm
on-farm culture system to detect infected quarters at
dry-off is an interesting option to decrease antibiotic
use without any negative effects on udder health or
milk production in the first 120 d of the subsequent
lactation compared with BDCT.
Key words: dry period, selective antibiotic treatment,
on-farm culture, mastitis, intramammary infection.Zoetis (Canada)Canadian Dairy CommissionAgriculture and Agri-Food CanadaFonds de Recherche du Québec – Nature et TechnologiesUniversity of Prince Edward IslandCanadian Dairy NetworkNatural Sciences and Engineering Research Counci
Lifetime effects of infection with bovine leukemia virus on longevity and milk production of dairy cows
No full textDevelopment of a linear regression model to estimate within herd prevalence of bovine leukemia virus (BLV) from antibody titer detected by ELISA in bulk tank milk (BTM)
No full textBLV antibody ELISA titers using BTM with the true herd prevalence (Nekouei, 2015). BTM antibody titers can be used as a cost-effective test to estimate the within-herd-prevalence of
BLV. The objective is to build and validate new BLV ELISA assay to predict the within-herd-prevalence using the BTM antibody titers with repeated testing over a 3 year period.
Material and methods: The true within herd prevalence of BLV was calculated on 34 Maritime dairy farms by individually testing all lactating cows with an ELISA assay using a milk sample for a three year period. BLV antibodies in BTM were tested in triplicate and averaged every 2 months in the first year. The correlation between the true within-herd-prevalence and the mean BLV titre from all 3 rounds of the BTM BLV testing was assessed using simple linear regression and validated using a leave-one-out cross validation test.
Results: A total of 4552 individual cows from the 34 farms were tested to determine the with-in herd prevalence . The mean BTM Elisa titre was transformed to square root to meet the assumptions for statistical analysis. BTM testing correlated well with the true within-herd prevalence (R2= 0.61 %). A cross validation test of the final model revealed a very good fit (minimum pseud R2: 0.78 %).
Conclusion: Development and validation of this model could be used as an economical tool to determine the with-in herd prevalence for BLV
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Bayesian estimation of diagnostic accuracy of somatic cell counts history and on-farm milk culture using Petrifilm® to identify quarters or cows that should be treated with antimicrobials in selective treatment protocols at dry off
No full textBayesian latent class models were used to estimate the test accuracy (sensitivity (Se), specificity (Sp), and predictive values (NPV and PPV)) of cow-level somatic cell counts (SCC) data, quarter-level Petrifilm® on-farm milk culture, and quarter-level standard milk bacteriology for the identification of quarters that should possibly be treated with antimicrobials at dry off in dairy cows. Data of 282 cows from 9 dairy herds in Québec, Canada, with bulk tank SCC < 250,000 cells/mL were used. Estimated median herd-prevalence of infections that should be treated was 16.2 % (95 % credibility interval (CI): 11.0--22.7). Se and Sp estimates for quarter-milk culture using Petrifilm® were 82.2 % (95 %CI: 74.0--89.5) and 62.0 % (95 %CI: 58.6--65.6), respectively. Se and Sp for quarter-milk standard bacteriology were 67.4 % (95 %CI: 55.8--81.2) and 79.6 % (95 %CI: 76.4--83.0), respectively. Se and Sp of different SCC scenarios and thresholds were estimated. For first parity cows, using only the last Dairy Herd Improvement (DHI) test SCC with a threshold of 100,000 cells/mL appeared quite accurate, with Se, Sp, PPV, NPV and reduction of antimicrobial usage of 85.6 % (95 %CI: 69.6--95.6), 86.0 % (95 %CI: 80.0--91.7), 58.0 % (95 %CI: 42.3--74.2), 96.4 % (95 %CI: 91.3--99.0), and 75.3 % (95 %CI: 70.7--79.3), respectively. For cows of [greater than or equal to] 2nd parity, using only the last DHI test SCC with a threshold of 200,000 cells/mL resulted in Se, Sp, PPV, NPV and reduction of antimicrobial usage of 75.3 % (95 %CI: 55.8--87.3), 84.0 % (95 %CI: 78.8--89.3), 47.2 % (95 %CI: 32.0--63.7), 94.7 % (95 %CI: 89.0--97.6), and of 77.0 % (95 %CI: 73.3--80.3), respectively. Adding quarter-level milk culture using Petrifilm® to cows identified as unhealthy using cow-level SCC data improved the test accuracy (mainly the PPV) and further reduced the use of antimicrobials. For instance, in [greater than or equal to] 2nd parity cows, using only the last DHI SCC with a threshold of 200,000 cells/mL, adding a subsequent Petrifilm® test increased the reduction from 77.0 % (95 %CI: 73.3--80.3) to 89.5 % (95 %CI: 86.7--91.8). Considering the availability of SCC data, the easiness of using just the last DHI test, and the high NPV that could be achieved, producers may consider using just the last DHI test as a potential tool to identify cows that should be treated with antimicrobials at dry off. It may be used alone or in combination with quarter-level on-farm Petrifilm® milk culture on high SCC cows to further reduce the use of antimicrobials by identifying quarters that need to be treated
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