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Disease signs reported in south‐eastern Australian dairy cattle while grazing Brassica species
Author(s) -
MORTON JM,
CAMPBELL PH
Publication year - 1997
Publication title -
australian veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.382
H-Index - 59
eISSN - 1751-0813
pISSN - 0005-0423
DOI - 10.1111/j.1751-0813.1997.tb14169.x
Subject(s) - outbreak , incidence (geometry) , brassica , herd , disease , dairy cattle , veterinary medicine , population , cattle diseases , medicine , grazing , environmental health , biology , agronomy , zoology , pathology , physics , optics
Objective To estimate the relative frequency of various disease signs in dairy cattle fed brassicas in south‐eastern Australia, to estimate the incidence of disease signs within affected groups and to identify risk factors for commonly reported signs in brassica‐fed dairy cows. Design A case series study and a case‐control study. Procedures Case data was collected using an incident reporting system. Herd managers and veterinarians recorded details about disease incidents in brassica‐fed dairy cattle in summer and autumn 1995 using a standard questionnaire. Potential risk factors for photosensitisation were assessed using a case‐control study. Results Disease signs were reported in 66 groups of brassica‐fed dairy cattle. Photosensitisation and bloat were the more frequently reported signs. While high incidences were reported in some groups, the incidence of disease signs was low within most affected groups. Photosensitisation occurred more frequently among groups of cows fed brassica crops treated with nitrogenous fertilisers or which were low yielding. Risks of other disease signs were greatest while the first one quarter of the crop was grazed. Conclusions In the study population, most disease outbreaks occurring in brassica‐fed cattle were of low incidence. However, some high incidence outbreaks occurred. Results from this study suggest that important risk factors exist for disease signs in brassica‐fed dairy cattle. Further studies are required if these risk factors are to be fully identified. This would allow the development of preventative strategies for high incidence disease outbreaks while feeding brassicas to dairy cattle.