A serious health problem of newborn calves was recognized 20 years ago and termed “weak calf syndrome”(WCS). The Bovine Virus Diarrhea (BVD) virus was often isolated from affected calves and from these herds. In recent years, veterinarians have again been looking at the effects of the BVD virus on the fetus.
Bagley, Clell, "Weak Calf Syndrome or BVD Fetal Infection" (1997). All Current Publications. Paper 450.