That just sucks.  After reading up on IBR it looks like it could have been prevented with proper vaccination when bought or as younger calves if they were from his own cows.  A Texas A&M bulletin mentioned death in only about 5% of the cases.  http://www.ansci.wisc.edu/jjp1/ansci_repro/lab/diseases_2002/ibr/beef_ibr_texas_am.pdf

When dealing with any livestock, a complete vaccination program is needed.  It is just like raising children, they need their proper vaccinations.