An observational study of ear-tagged calf mortality (1 to 100 days) on Irish dairy farms and associations between biosecurity practices and calf mortality on farms participating in a Johne's disease control program.

Autor:	McAloon CG; Section of Herd Health and Animal Husbandry, School of Veterinary Medicine, University College Dublin, Stillorgan Road, Dublin 4, D04 W6F6, Ireland. Electronic address: mcaloonconor@gmail.com., Tratalos JA; Centre for Veterinary Epidemiology and Risk Analysis, University College Dublin, Stillorgan Road, Dublin 4, D04 W6F6, Ireland., O'Grady L; Section of Herd Health and Animal Husbandry, School of Veterinary Medicine, University College Dublin, Stillorgan Road, Dublin 4, D04 W6F6, Ireland; School of Veterinary Science and Medicine, University of Nottingham, College Road, Sutton Bonington, Leicestershire, United Kingdom, LE12 5RD., Green MJ; School of Veterinary Science and Medicine, University of Nottingham, College Road, Sutton Bonington, Leicestershire, United Kingdom, LE12 5RD., Gavey L; Animal Health Ireland, Carrick-on-Shannon, N41 WN27, Ireland., Graham D; Animal Health Ireland, Carrick-on-Shannon, N41 WN27, Ireland., More SJ; Section of Herd Health and Animal Husbandry, School of Veterinary Medicine, University College Dublin, Stillorgan Road, Dublin 4, D04 W6F6, Ireland; Centre for Veterinary Epidemiology and Risk Analysis, University College Dublin, Stillorgan Road, Dublin 4, D04 W6F6, Ireland., McGrath G; Centre for Veterinary Epidemiology and Risk Analysis, University College Dublin, Stillorgan Road, Dublin 4, D04 W6F6, Ireland., Mee JF; Animal and Bioscience Research Department, Teagasc, Moorepark Research Centre, Fermoy, P61 C997 Cork, Ireland.
Jazyk:	angličtina
Zdroj:	Journal of dairy science [J Dairy Sci] 2023 Jul; Vol. 106 (7), pp. 4966-4977. Date of Electronic Publication: 2023 May 22.
DOI:	10.3168/jds.2022-22519
Abstrakt:	Postnatal mortality among replacement stock has a detrimental effect on the social, economic, and environmental sustainability of dairy production. Calf mortality rates vary between countries and show differences in temporal trends; most, however, are characterized by high levels of between-farm variability. Explaining this variation can be difficult because herd-level information on management practices relevant to calf health is often not available. The Irish Johne's Control Programme (IJCP) contains a substantial on-farm monitoring program called the Veterinary Risk Assessment and Management Plan (VRAMP). Although this risk assessment is largely focused on factors relevant to the transmission of paratuberculosis, many of its principles are good practice biocontainment policies that are also advocated for the protection of calf health. The objectives of this study were (1) to quantify mortality in ear-tagged Irish dairy calves between 2016 and 2020 using both survival and risk approaches, (2) to determine risk factors for 100-d cumulative mortality hazard in ear-tagged Irish dairy calves between 2016 and 2020, (3) to determine whether 100-d cumulative mortality hazard was higher in ear-tagged calves within herds registered in the IJCP versus those that were not registered in the IJCP and whether there were differences between these cohorts over time, and (4) within IJCP herds, to determine whether VRAMP score or changes in VRAMP score were associated with 100-d cumulative mortality hazard. Excluding perinatal mortality, the overall 100-d cumulative mortality hazard was 4.1%. Calf mortality was consistently underestimated using risk approaches that did not account for calf censoring. Cox proportional hazards models showed that cumulative mortality hazard was greater in male calves; particularly, calves born to Jersey breed dams and those with a beef breed sire. Mortality hazard increased with increasing herd size, was highest in calves born in herds that contract-reared heifers, and lowest in those born in mixed dairy-beef enterprises. Mortality hazard decreased over time with the mortality hazard in 2020 being 0.83 times that of 2016. Mortality hazard was higher in IJCP-registered herds than nonregistered herds (hazard ratio 1.06, 95% CI 1.01-1.12), likely reflecting differences in herds that enrolled in the national program. However, we detected a significant interaction between IJCP status (enrolled vs. not enrolled) and year (hazard ratio 0.96, 95% CI 0.92-1.00), indicating that the decrease in mortality hazard between 2016 and 2020 was greater in IJCP herds versus non-IJCP herds. Finally, increasing VRAMP scores (indicating higher risk for paratuberculosis transmission) were positively associated with increased calf mortality hazard. Postnatal calf mortality rates in Irish dairy herds declined between 2016 and 2020. Our study suggests that implementation of recommended biocontainment practices to control paratuberculosis in IJCP herds was associated with a reduction in calf mortality hazard. (The Authors. Published by Elsevier Inc. and Fass 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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