Colostrum was collected and pooled from each of five cows in three experimental groups: group I cows received intramuscular and intramammary inoculations of adjuvanted modified live Ohio Agricultural Research and Development Center rotavirus vaccine; group II cows were injected intramuscularly with a commercial modified-live rota-coronavirus vaccine; and group III cows were uninoculated controls. Pooled colostrum from group I cows had higher (P less than 0.05) enzyme-linked immunosorbent assay (ELISA) immunoglobulin G (IgG1) and virus neutralization (VN) rotavirus antibody titers (ELISA IgG1 = 2,413,682; VN = 360,205) than did colostrum from group II (ELISA IgG1 = 8,192; VN = 4,395) or group III cows (ELISA IgG1 = 5,916; VN = 2,865). The antibody titers of these last two colostrum pools did not differ (P greater than 0.05). Samples of these colostrum pools were fed as daily supplements (percent [vol/vol] in cow's milk infant formula) to 28 newborn, unsuckled, antibody-seronegative, male Holstein calves. Eight calves received no supplemental colostrum. The calves were orally challenged with virulent bovine rotavirus and monitored daily for diarrhea and fecal rotavirus shedding. Diarrhea and rotavirus shedding occurred in the eight calves fed no supplemental colostrum and persisted longest in this group. The pooled colostrum from group I cows protected eight of eight calves from both rotavirus diarrhea and shedding when fed as a 1% supplement. The pooled colostrum from neither group II nor group III cows protected 12 other calves against rotavirus diarrhea or shedding when fed at the same concentration (1%). Six rotavirus-challenged calves fed 0.1% supplemental colostrum from group I cows and two calves fed 10 and 50% supplemental colostrum from control cows displayed partial passive immunity, exemplified by delayed onset and shortened duration of rotavirus-associated diarrhea and virus shedding.

Faeces and, or, paired sera were collected from cows in six dairy herds with classical winter dysentery. Similar samples were collected from cows in three other dairy herds experiencing non-haemorrhagic diarrhoea during the survey period. Coronavirus was the only enteric pathogen identified by immune electron microscopy (IEM) in all six outbreaks, occurring in 26 of 29 (90 per cent) of the affected cows and in one of 11 normal cows from the same herds. Nineteen of 26 affected cows (73 per cent) developed greater than four-fold increases in neutralising antibody titres to the Mebus strain of bovine coronavirus, compared with two of eight normal cows in the same herds. No cows showed greater than four-fold increases in antibody titres to bovine virus diarrhoea virus. None of the cows from the three herds with non-haemorrhagic diarrhoea shed coronavirus in faeces detectable by IEM or developed greater than two-fold rises in coronavirus antibody titres in paired sera. No enteric pathogens were identified in two of the herds. However, two cows in the third herd shed a group B rotavirus detected by IEM. These findings provide additional evidence for a possible role for bovine coronavirus in the aetiology of winter dysentery. Furthermore, this is the first report of a group B rotavirus associated with diarrhoea in adult cattle.

The prevention and control of bovine viral diarrhea virus (BVDV) infections in cattle are of worldwide concem. 1,5 Although our understanding of the complex pathogenesis of BVDV has progressed, many aspects of BVDV infection remain elusive. A unique and significant aspect of the pathogenesis of BVDV is the development of persistently infected animals following in utero infection.1 Although persistently infected animals may constitute only 1-2% of the cattle population 2 they are considered the main source of infection and may serve as reservoirs. 1,5 Due to the epidemiological significance of persistently infected animals, it is important that possible methods of transmission be investigated. Currently, the recommended prevention and control measures for BVDV are centered around the identification and removal of persistently infected animals and the judicious use of BVDV vaccines. 4,6 Unfortunately, the identification of persistently infected animals has not been emphasized until recently and remains impractical. The purpose of this report is to emphasize the epidemiological significance of animals persistently infected with BVDV, especially in relation to embryo transfer procedures.A 5-month-old Holstein heifer, persistently infected with BVDV, was identified in a dairy herd with a history of BVDV infection by virus isolation from nasal and vaginal swabs and serum. The heifer had no detectable levels of BVDV serum antibodies (in indirect fluorescence assay [IFA]) and was kept in isolation for observation and testing. Estrus first was detected at 14 months of age. Following the third heat cycle the heifer was superovulated with follicle-stimulating hormone (days 11-14) and inseminated with BVDV-negative semen (confirmed negative by virus isolation) during the subsequent estrous. Embryo collection was attempted on day 7 (estrus day 0) by standard whole body uterine flush using 2 liters of Dulbecco's phosphate-buffered saline containing 3% BVDV-negative fetal bovine serum (confirmed negative by virus isolation). Virus was not isolated from the flush medium prior to the uterine flush. Only 3 unfertile eggs were identified by microscopic examination in the uterine flush fluid (2 liters).The titers of BVDV were quantitated in various samples collected from the persistently infected heifer by virus isolation from 10-fold dilutions of the samples. One milliliter of each dilution was inoculated in replicates of 3 onto BVDVnegative secondary bovine turbinate cells passaged 5-10 times in Dulbecco's minimum essential medium containing 10% horse serum. The inoculum was removed after 1 hour and From the Food Animal Health Research Program, Ohio Agricultural Research and Development Center, Wooster OH 44691 (Brock, Redman, Irvine), and the Department of Veterinary Science, South Dakota State University, Brookings, SD 57007 (Vickers).Received for publication May 25, 1990. replaced with fresh medium. The cell cultures were incubated for 5 days at 37 C in 5% CO 2 . Noncytopathic BVDV was detected by IFA using an anti-BVDV po...

A procedure for extracting rotaviral double-stranded ribonucleic acid (RNA) directly from fecal and intestinal specimens collected from calves and pigs is described. This procedure provides a rapid, simple, reproducible method of obtaining rotaviral double-stranded RNA preparations suitable for electrophoretic analysis in polyacrylamide-agarose composite gels. The rotaviral genome electrophoretic migration pattern produced by double-stranded RNA extracted directly from a specimen by this procedure was qualitatively identical to the electrophoretic migration pattern obtained with double-stranded RNA extracted from purified rotavirus derived from the same specimen. Direct extraction of specimens containing porcine rotavirus-like virus by this procedure gave preparations that had electrophoretic migration patterns similar, but not identical, to the characteristic electrophoretic migration pattern of the rotaviral genome. Sufficient rotaviral double-stranded RNA could be extracted from 6 ml of fecal or intestinal specimen by this procedure to permit 15 or more electrophoretic assays.

The effect of combined supplementation with selenium and Vitamin E upon fertilization of ova was evaluated in beef cattle maintained on either an adequate or inadequate nutrition. Fertilization of ova was 100% in those females receiving supplemental selenium/vitamin E and on an adequate plane of nutrition. Interaction between plane of nutrition and selenium/vitamin E was significant for percent fertility.