Veterinary session

Actinobacillus pleuropneumonia is a porcine bacterial respiratory disease of worldwide great economic significance. Losses associated with this condition arise from mortality of fatteners, from increasing costs of treatment and prevention, and also from worsening production parameters. One of the few possible ways of combating this disease is vaccination of progeny against Actinobacillus pleuropneumoniae. Efficacy of currently available vaccines is negatively influenced by the presence of colostral antibodies in swine sera. Large amount of colostral antibodies present at the time of vaccination will not confer adequate protection. Determination of the time of colostral antibody depletion is suggested to circumvent this problem. For this purpose we use an IDEXX Chekit App ApxIV commercial ELISA. This test is based on the detection of anti Actinobacillus pleuropneumoniae ApxIV toxin antibodies. According to our current knowledge, this toxin is only produced by Actinobacillus pleuropneumoniae strains (not by other members of the Pasteurellaceae family), and only produced in vivo upon natural infection and not by vaccination. Seroprofiling for detecting the depletion of colostral antibodies typically involves taking blood samples from 8-10 animals per age group from batches of 6, 8, 10, 12, 14 weeks old animals from a given herd and testing by the above mentioned ELISA test to determine the age group when the amount of colostral antibodies reaches its lowest value. The aim of this study is to examine the possibility to reduce the number of samples needed for seroprofiling by determining a constant rate of colostral antibody depletion. For this purpose we analyzed historical data gathered in our Laboratory from 80 Hungarian swine herds between 2004 and 2011 and attempted to create a regression equation from these, describing the decline of colostral antibodies from only one age group. We attempted to test the validity of this model through seroprofiling various swine herds.