Herd-level prevalence of bovine leukemia virus, Salmonella Dublin, and Neospora caninum in Alberta, Canada, dairy herds using ELISA on bulk tank milk samples.

Autor:	Shaukat W; Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada, T2N 4N1., de Jong E; Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada, T2N 4N1., McCubbin KD; Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada, T2N 4N1; One Health at UCalgary, University of Calgary, Calgary, Alberta, Canada, T2N 4Z6., Biesheuvel MM; Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada, T2N 4N1., van der Meer FJUM; Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada, T2N 4N1., De Buck J; Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada, T2N 4N1., Lhermie G; Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada, T2N 4N1; The Simpson Centre for Food and Agricultural Policy, The School of Public Policy, University of Calgary, Calgary, Alberta, Canada, T2P 1H9., Hall DC; Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada, T2N 4N1., Kalbfleisch KN; Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada, T2N 4N1., Kastelic JP; Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada, T2N 4N1., Orsel K; Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada, T2N 4N1., Barkema HW; Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada, T2N 4N1; One Health at UCalgary, University of Calgary, Calgary, Alberta, Canada, T2N 4Z6; Department of Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada, T2N 4N1. Electronic address: barkema@ucalgary.ca.
Jazyk:	angličtina
Zdroj:	Journal of dairy science [J Dairy Sci] 2024 Oct; Vol. 107 (10), pp. 8313-8328. Date of Electronic Publication: 2024 May 31.
DOI:	10.3168/jds.2023-24611
Abstrakt:	Endemic infectious diseases remain a major challenge for dairy producers worldwide. For effective disease control programs, up-to-date prevalence estimates are of utmost importance. The objective of this study was to estimate the herd-level prevalence of bovine leukemia virus (BLV), Salmonella enterica ssp. enterica serovar Dublin (Salmonella Dublin), and Neospora caninum in dairy herds in Alberta, Canada, using a serial cross-sectional study design. Bulk tank milk samples from all Alberta dairy farms were collected 4 times, in December 2021 (n = 489), April 2022 (n = 487), July 2022 (n = 487), and October 2022 (n = 480), and tested for antibodies against BLV, Salmonella Dublin, and N. caninum using ELISA. Herd-level apparent prevalence was calculated as positive herds divided by total tested herds at each time point. A mixed-effect modified Poisson regression model was employed to assess the association of prevalence with region, herd size, herd type, and type of milking system. Apparent prevalence of BLV was 89.4%, 88.7%, 86.9%, and 86.9% in December, April, July, and October, respectively, whereas for Salmonella Dublin apparent prevalence was 11.2%, 6.6%, 8.6%, and 8.5%, and for N. caninum apparent prevalence was 18.2%, 7.4%, 7.8%, and 15.0%. For BLV, Salmonella Dublin, and N. caninum, a total of 91.7%, 15.6%, and 28.1% of herds, respectively, were positive at least once, whereas 82.5%, 3.6%, and 3.0% of herds were ELISA positive at all 4 times. Compared with the north region, central Alberta had a high prevalence (prevalence ratio [PR] = 1.13) of BLV antibody-positive herds, whereas south Alberta had a high prevalence (PR = 2.56) of herds positive for Salmonella Dublin antibodies. Furthermore, central (PR = 0.52) and south regions (PR = 0.46) had low prevalence of N. caninum-positive herds compared with the north. Hutterite colony herds were more frequently BLV positive (PR = 1.13) but less frequently N. caninum-positive (PR = 0.47). Large herds (>7,200 L/d milk delivered ∼>250 cows) were 1.1 times more often BLV positive, whereas small herds (≤3,600 L/d milk delivered ∼≤125 cows) were 3.2 times more often N. caninum positive. For Salmonella Dublin, Hutterite colony herds were less frequently (PR = 0.07) positive than non-colony herds only in medium and large strata but not in small stratum. Moreover, larger herds were more frequently (PR = 2.20) Salmonella Dublin-positive than smaller herds only in non-colony stratum but not in colony stratum. Moreover, N. caninum prevalence was 1.6 times higher on farms with conventional milking systems compared with farms with an automated milking system. These results provide up-to-date information of the prevalence of these infections that will inform investigations of within-herd prevalence of these infections and help in devising evidence-based disease control strategies. (The Authors. Published by Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)
Databáze:	MEDLINE
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