Proceedings of the 10th International Colloquium on Paratuberculosis

#116
Associations between clinical paratuberculosis, production performance and species
interaction in co-grazing pastoral ruminant species in New Zealand
Cord Heuer, Cristobal Verdugo, Peter R Wilson
Massey University, New Zealand
Aim: The objective <strong>of</strong> this study was to evaluate farmer awareness and observations <strong>of</strong> clinical paratuberculosis
(Ptb), and <strong>the</strong> impact <strong>of</strong> observed Ptb on productivity in mixed species, pastoral farming systems in New
Zealand.
Methods: Twenty-six veterinary practices were contracted to mail out questionnaires to 8,314 commercial
livestock farming clients in five <strong>of</strong> 16 regions <strong>of</strong> New Zealand. The requested information included herd
characteristics and denominator data, observed clinical Ptb and records, as well as estimates <strong>of</strong> mortality and
reproductive performance in sheep, deer, beef and dairy cattle. This paper presents farmer awareness about
Ptb and annual rates <strong>of</strong> observed clinical Ptb in <strong>the</strong>se species, adjusted for region, farm type and herd/flock
sizes. For <strong>the</strong> analysis <strong>of</strong> production effects, reproductive performance and mortality were classified as low or
average/high for each species. For each species enterprise, a multivariable logistic regression model assessed
<strong>the</strong> relationship between production performance and clinical Ptb, using co-grazing species, region, farm type
and farm size as co-variables. A second model evaluated <strong>the</strong> association between clinical Ptb for each species
and o<strong>the</strong>r species present or absent on farm.
Results: This study will be completed by end <strong>of</strong> May 2009. A total <strong>of</strong> 1,713 (20.6%) commercial farmers
returned <strong>the</strong> questionnaire with valid data. Results <strong>of</strong> <strong>the</strong> analysis will be available and presented at <strong>the</strong> conference.
Conclusions: Expected inferences include <strong>the</strong> perceived importance that farmers attribute to Ptb, population
based estimates <strong>of</strong> <strong>the</strong> impact <strong>of</strong> clinical Ptb on productivity, and associations between clinical Ptb and
on-farm species composition.
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