A simplified scored system for the diagnosis of diarrhoea and respiratory diseases in dairy calves
The present research paper aims to validate a simplified calf health scoring chart (SIM-score) for calf diarrhoea and calf respiratory disease (RD) diagnosis and determine the associations between passive immune transfer and growth morbidity, and mortality in dairy calves. A blood sample was taken from Holstein's calves at 1-7 days of age to determine serum total protein concentration by refractometry (< 5.2 g/dL was indicative of the failure of passive transfer [FPT]). Subsequently, calves were weekly weighted for 9 weeks with a heart-girth measuring tape and clinically evaluated for diarrhoea and RD diagnosis using a calf health scoring chart of the University of Wisconsin (WIN-score, as a reference method) and a SIM-score. The SIM score was based on observational clinical signs for diagnosing RD and a cleanliness score for diagnosing diarrhoea. The agreement between WIN-score and SIM-score was estimated by calculating Kappa's coefficient. Logistic regression models, risk factors for FPT, diarrhoea events, RD events, and death events were assessed. The associations between already mentioned predictors and the growth of calves were assessed by fitting linear regression with repeated measures. Calves with FPT weighted 2.49 Kg less (P= 0.020) had 4.03 (P= 0.037) times greater odds for RD and had 2.74 times greater odds of death (P= 0.092) than their mates. The passive immune transfer was not associated with diarrhoea (P= 0.839). Finally, both charts of scoring had a good and poor agreement for the diagnosis of RD and diarrhoea, respectively. In conclusion, a successful passive transfer of immunity improves the development of the calves, has a protective effect against RD, and decreases the odds of death. On the other hand, we concluded that the SIM score is a valuable test for diagnosing RD but not for diagnosing diarrhoea.
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