352
Views
20
CrossRef citations to date
0
Altmetric
Scientific Article

A questionnaire-based cross-sectional study of clinical Johne's disease on dairy farms in New Zealand

, &
Pages 34-43 | Received 06 Apr 2008, Accepted 08 Dec 2008, Published online: 16 Feb 2011
 

Abstract

AIM: To investigate associations between both farm management factors and breed of dairy cow, and the incidence of farmer-observed clinical Johne's disease (JD) on dairy farms in four major dairying regions in the North Island of New Zealand.

METHODS: A questionnaire-based cross-sectional study was conducted to identify associations between both farm management practices and breed of dairy cow, and the incidence of clinical cases of JD suspected by farmers, on dairy farms in the Waikato, Taranaki, Wellington-Manawatu-Wanganui, and Wairarapa regions of New Zealand. Using multinomial logistic regression, the frequency of management practices was compared between farms on which no clinical cases of JD were observed, farms on which the observed incidence was low, and farms on which the observed incidence was high.

RESULTS: Of the 427 responding farmers, 201 (47%) had suspected clinical cases of JD in their herd in the preceding 5 years. Only 56/427 (13%) farmers observed an average annual incidence of >0.5 cases/100 cows during this period. Ninety percent (203/225) of farmers that had not observed clinical cases and 21% (42/201) of farmers that had observed clinical cases did not consider the disease a serious problem. Farmers and veterinarians had a moderate level of agreement regarding the JD status of a farm. Their perceptions were in agreement for 86% (38/44) of the high-incidence herds for which both a farmer's and a veterinarian's perception were available.

The presence of Jersey cows in the herd and the purchase of bulls were most strongly associated with the incidence of clinical JD. Grazing calves in the hospital paddock, purchase of a large percentage of heifers, larger-than-average herds within our sample, and the use of induction were also positively associated with JD. Farmers who ensured heifers were at least 2 years old, rather than younger, when mixed with adult stock were likely to observe fewer cases of clinical JD.

CONCLUSIONS AND CLINICAL RELEVANCE: The annual incidence of farmer-observed clinical cases of JD was low, and the disease was generally regarded as of little importance by farmers. Farmers that had a high proportion of Jersey cows or that purchased bulls from either one or more than four sources were most likely to report clinical cases of JD. Management practices that could aid in the control of JD are the purchase of bulls free of JD, ensuring that calves do not graze in the hospital paddock, and ensuring that young stock are at least 2 years old prior to contact with adult stock.

Acknowledgements

Funding for this study was provided by Meat New Zealand and Livestock Improvement Corporation. The corresponding author's scholarship was provided by the Agricultural and Marketing Research and Development Trust. Participating veterinary practices were Awapuni Veterinary Services, Bush Veterinary Services, Cambridge Vet Services, Coastal Veterinary Services, Dannevirke Veterinary Services, Franklin Veterinary Services, Horowhenua Veterinary Services, Inglewood Veterinary Services, Massey University Veterinary Clinic, Manawatu Veterinary Services, Morrinsville Animal Health Centre, Okato Veterinary Clinic, New Plymouth-Stratford District Vet Services, Te Awamutu Animal Health Centre, Tokoroa & District Vet Services, Wairarapa Veterinary Services, and Wanganui Vet Services.

Log in via your institution

Log in to Taylor & Francis Online

PDF download + Online access

  • 48 hours access to article PDF & online version
  • Article PDF can be downloaded
  • Article PDF can be printed
USD 61.00 Add to cart

Issue Purchase

  • 30 days online access to complete issue
  • Article PDFs can be downloaded
  • Article PDFs can be printed
USD 213.00 Add to cart

* Local tax will be added as applicable

Related Research

People also read lists articles that other readers of this article have read.

Recommended articles lists articles that we recommend and is powered by our AI driven recommendation engine.

Cited by lists all citing articles based on Crossref citations.
Articles with the Crossref icon will open in a new tab.