Abstract

As part of an ongoing project to identify quantitative trait loci (QTL) for economically important traits in New Zealand dairy cows, a vaccine trial was conducted to measure the antibody response of 10 week old Friesian-Jersey crossbred calves to two antigenic compounds of a clostridial vaccine (Clostridium novyi B and Clostridium tetani toxoids). Blood samples were collected from 469 calves prior to vaccination at 10 weeks of age, prior to re-vaccination at 13 weeks of age and at 16 and 22 weeks of age. ELISA assays using conjugated rabbit anti-bovine IgG were conducted for both toxoids. Correlations and explanatory variables were calculated using correlation and general linear model (GLM) procedures in SAS. Antibody response to both toxins were relatively low after the first vaccination (week 13), but were boosted to high levels after revaccination (week 16). GLM analysis revealed a moderate sire effect contributing to the variability seen in the 13 week test against C. tetani (P=0.001) and the 16 week test against C. novyi (P=0.01). This variation in individual antibody response will be used in future research to identify genetic factors controlling the acquisition of immunity.

SJ, Harcourt, BM Buddle, K Hamel, LR McNaughton, and RJ Spelman

Proceedings of the New Zealand Society of Animal Production, Volume 64, Hamilton, 110-114, 2004