Predicting Susceptibiliy to Johne's Disease in New Zealand Dairy Cattle

Abstract Text: Johne's disease (JD) is a chronic, inflammatory gastrointestinal disease. JD has a significant economic impact on the NZ dairy industry. The objective of this study was to develop a predictive genomic test for susceptibility to JD in NZ dairy cattle. Cows were confirmed as JD affected (JD+) by ELISA of milk and serum samples. 1,833 JD+ cows were genotyped using the Illumina SNP770 Bead Chip. 6,849 Control cow genotypes (50K) representing the general population were chosen to match the breed proportion profile of the JD+ cows and their genotypes were imputed to 770K for analysis. The genomic merit for susceptibility to JD of 1 Mb windows across the genome was estimated using a Bayes B model. Test accuracy was evaluated using 10-fold cross-validation. Results suggest a genomic test for JD susceptibility with prediction accuracy at a level suitable for practical use is possible.

Keywords:

dairy cattle

Johne's Disease

genomics