PSVI-2 The effect of a recombinant Mannheimia haemolytica leukotoxoid on the health and growth performance of high-risk, newly received stocker cattle metaphylactically treated with tilmicosin

Crossbred male beef calves (n = 259; bulls = 134, steers = 125; body weight = 250 ± 3.4 kg) approximately 6 months of age and considered high-risk for developing bovine respiratory disease arrived on 3 dates (block) and were stratified by arrival castrate status and weight to be evenly distributed across pens (8 pens/block; 9 to 12 calves/pen). The pens were randomly assigned to 1 of 2 treatments: 1) Nuplura PH (administration of a Mannheimia haemolytica leukotoxoid at processing) or 2) Control (no M. haemolytica leukotoxoid). All cattle received tilmicosin on d 0 with a 5-d post-metaphylactic interval. Body weights were recorded on d -1, 0, 14, 28, 41 and 42. Blood was collected on d -1, 14, 28, and 42 and sera were harvested to determine serum neutralization titers for bovine virus diarrhea (BVD) type I and bovine anti-M. haemolytica leukotoxin antibodies. Calves were observed daily for signs of morbidity. Body weight and average daily gain were not affected (P ≥ 0.26) by treatment. The percentage of calves administered 1, 2, or 3 antibiotic treatments for clinical bovine respiratory disease did not differ (P ≥ 0.35). There was a tendency for mortality to be greater for Control compared to Nuplura PH (1.6 vs 0.0%; P = 0.10). Calves administered Nuplura PH possessed greater antibody response against M. haemolytica leukotoxin on d 14, 28, and 42 compared to Control calves (P < 0.01). There was no treatment × day interaction for antibody titers against BVD (P = 0.98). The use of a M. haemolytica leukotoxoid had no effect on growth performance and morbidity for the 42-d following receiving in this small-pen study, but reduced the incidence of mortality and did not interfere with antibody response to BVD vaccination in high-risk, newly received calves metaphylactically treated with tilmicosin on arrival.

Complete Genome Sequence of a Hobi-Like Virus Isolated from a Nelore Cow with Gastroenteric Disease in the State of São Paulo, Brazil

ABSTRACT The Hobi-like virus presents antigenic and molecular differences in relation to bovine virus diarrhea virus 1 and 2. The description of the complete genome of the Hobi-like virus SV757/15, isolated from a Nelore cow with gastroenteric disease in Brazil, will help in understanding the evolution and diversity of pestiviruses.

Pestivirus control programs: how far have we come and where are we going?

Classical swine fever (CSF) is endemic in large parts of the world and it is a major threat to the pig industry in general. Vaccination and stamping out have been the most successful tools for the control and elimination of the disease. The systematic use of modified live vaccines (MLV), which are very efficacious and safe, has often preceded the elimination of CSF from regions or countries. Oral vaccination using MLV is a powerful tool for the elimination of CSF from wild boar populations. Bovine virus diarrhea (BVD) is endemic in bovine populations worldwide and programs for its control are only slowly gaining ground. With two genotypes BVD virus (BVDV) is genetically more diverse than CSF virus (CSFV). BVDV crosses the placenta of pregnant cattle resulting in the birth of persistently infected (PI) calves. PI animals shed enormous amounts of virus for the rest of their lives and they are the reservoir for the spread of BVDV in cattle populations. They are the main reason for the failure of conventional control strategies based on vaccination only. In Europe two different approaches for the successful control of BVD are being used: Elimination of PI animals without or with the optional use of vaccines, respectively.

Perosomus elumbis in a Holstein calf infected with bovine viral diarrhea virus

SummaryThe detection of bovine viral diarrhea virus (BVDV) in a female Holstein calf presented with perosomus elumbis, a congenital anomaly, is reported here. A cow with dystocia was evaluated and an abnormal dead calf was detected during vaginal examination. The calf was retrieved via caesarean section and exhibited abnormalities characteristic of PE, such as vertebral and pelvic malformations. These abnormalities were further confirmed using radiographic and necropsy examinations. At necropsy cerebellar hypoplasia was an additional finding, which is a typical lesion associated with bovine virus diarrhea (BVD). Several tissue samples from the calf were tested for the presence of antigens of BVDV and bovine herpesvirus-1 (BHV-1) by ELISA. In addition, sera samples from the dam and calf were tested for the presence of antibodies against BVDV, BHV-1, and bluetongue disease virus (BTV) using a virus neutralization assay. Results indicated that the calf was congenitally infected with BVDV, whereas there was no evidence for the presence of BHV-1 and BTV. In the dam’s serum no antibodies against BVDV, BHV-1, and BTV were detected. Even though the etiology of perosomus elumbis is unknown, BVDV, which causes fetal anomalies at early gestation in cows, may have been a contributing factor in this case.