Probability of infection with Johne’s disease in dairy cows coming from infected dams versus uninfected dams
Summary
The most profound route of transmission of Paratuberculosis is oral uptake of the organism through milk or feces. However vertical transmission is suspected. This study aimed to compare the probability of infection in calves coming from infected dams versus uninfected dams. The data set contained milk and serum samples collected during routine milk research and collected by researchers. This was combined with pedigree data of 13097 cows to find mother-daughter combinations. Giving information to construct a 2x2 table which was used to perform a Fisher’s exact test to calculate a P-value and a confidence interval (CI): 0.079, 95%-CI: (-0.023; 0.157). Also the odds ratio was calculated with a CI: 2.309, 95%-CI: (0.801; 5.868). Neither being significant. Next a model was used to measure the influence of the infection status of the dam using repeated measures of the milk ELISA’s and MPRdata of 1388 cows. Giving a least square means of 2.6511 for a negative dam, 2.7043 for a positive dam and 2.6307 for missing dam infection status. However these results were not significant and due to intertwinement between dam infection status and herd and a necessary log-transformation of the s/p ratio these results do not represent an accurate assessment of the parameters.