Objective—To estimate prevalence of cattle persistently
infected (PI) with bovine viral diarrhea virus
(BVDV) at arrival at a feedlot, prevalence of chronically
ill and dead PI cattle, and the magnitude of excess
disease attributable to a PI animal.
Design—Cross-sectional and cohort studies.
Animals—2,000 cattle at the time they arrived at a
feedlot, 1,383 chronically ill cattle from 7 feedlots, and
1,585 dead cattle from a single feedlot.
Procedure—Skin biopsy specimens were collected
and evaluated via immunohistochemistry. Cattle were
characterized as either PI or not PI with BVDV on the
basis of characteristic immunostaining. Follow-up was
obtained for the 2,000 cattle from which samples
were collected at arrival, and health outcomes were
determined for cattle exposed and not exposed to a
Results—Prevalence of PI cattle was 0.3% at arrival,
2.6% in chronically ill cattle, and 2.5% in dead cattle.
Risk of initial treatment for respiratory tract disease
was 43% greater in cattle exposed to a PI animal,
compared with those not exposed to a PI animal.
Overall, 15.9% of initial respiratory tract disease
events were attributable to exposure to a PI animal.
Conclusions and Clinical Relevance—Relatively few
PI cattle arrive at feedlots. However, those cattle are
more likely to require treatment for respiratory tract
disease and either become chronically ill or die than
cattle that are not PI. In addition, they are associated
with an increase in the incidence of respiratory tract
disease of in-contact cattle. (J Am Vet Med Assoc
Case Description—An abortion storm occurred in a goat herd, resulting in 75 aborted kids and 1 neonatal death from December 2004 to February 2005.
Clinical Findings—Aborted fetuses ranged from being premature to past term. Laboratory findings in 4 of 5 aborted fetuses were consistent with herpesvirus abortion. A virus that yielded positive results with a fluorescent antibody test for bovine herpesvirus-1 was iso-lated and identified as caprine herpesvirus-1 (CpHV-1) via DNA sequence analysis.
Treatment and Outcome—Many does that aborted were rebred for kidding in late sum-mer. Most of the young wethers born in 2005 were sold; however, all of the young does were kept for breeding in fall. In November 2005, all 241 goats in the herd were tested for antibodies against CpHV-1 to identify goats that had seroconverted during the outbreak. No complications attributable to CpHV-1 were identified during kidding in 2006.
Clinical Relevance—On the basis of serologic findings, infection with CpHV-1 was not as-sociated with reduced reproductive success in the subsequent breeding.