Unvaccinated Calves Research Articles

Preliminary investigation into the usefulness of the indirect haemagglutination

Summary To give an impression of the usefulness of indirect haemagglutination (IHA) in the diagnosis of lungworm infections in cattle under practical conditions, five calves vaccinated against Dictyocaulus viviparus and five unvaccinated calves were periodically subjected to clinical, parasitological, and serological examinations over a period of seven months. All calves grazed on a lungworm-infected plot. 82% of the observations in unvaccinated calves, which were positive with respect to one or more of the used parameters, concerned IHA-positive animals which, however, showed negative results with the parasitic parameters. The titre variation of the serological examination was a further indication of the fact that the IHA detected antibodies against lungworm antigens. No indications of false positive reactions were obtained. An investigation carried out on 46 farms on the correlation between serological and clinical findings on lungworm infections revealed a positive correlation in 80% of the groups between results obtained with both methods. The authors consider that IHA offers good prospects for the diagnosis of lung-worm infections.

A cell culture vaccine against bovine ephemeral fever.

A vaccine was prepared from cell culture fluids harvested from the twelfth passage of the 919 strain of bovine ephemeral fever (BEF) virus in Vero cell cultures. Cattle were vaccinated subcutaneously with various combinations of strain 919 virus and adjuvants. Neutralising antibodies were assayed at various times after vaccination and some cattle were challenged by intravenous inoculation with the virulent 417WBC strain of BEF virus. Strain 919 virus of the third and twelfth passage levels in Vero cells produced neither fever, clinical illness nor detectable viraemia in 5 calves inoculated intravenously. Nor could viraemia be detected in 5 heifers receiving vaccine subcutaneously. When the vaccine was administered mixed with aluminium hydroxide adjuvant, the production of neutralising antibodies increased with an increase in the volume of vaccine from 2.5 ml to 10 ml and the response to 2 injections was significantly better than the response to a single injection. The neutralising antibody response was decreased when vaccine was diluted in phosphate buffered saline. The neutralising antibody response following 2 subcutaneous vaccinations with strain 919 virus mixed with aluminium hydroxide adjuvant was higher than that following intravenous inoculation with virulent virus. The vaccine-induced antibodies persisted for at least 12 months, and revaccination at this time led to an increase in the titre of neutralising antibody. Antibodies induced by a single subcutaneous administration of strain 919 virus mixed with Freund's complete adjuvant persisted for at least 40 weeks; those induced by vaccine containing Freund's incomplete adjuvant had virtually disappeared within 16 weeks. All these calves responded to vaccination with aluminium hydroxide-containing vaccine with increases in levels of neutralising antibodies. Of 26 vaccinated calves challenged with virulent BEF virus, 24 remained clinically normal. Two developed brief periods of pyrexia on the seventh day after challenge, but no other clinical signs. One of these calves had a viraemia that was demonstrated only by intravenous inoculation of a susceptible calf. The remaining calf had no detectable viraemia. All of 7 unvaccinated calves developed severe clinical BEF within 5 days of challenge. No disease attributable to the 919 virus occurred in 24 vaccinated pregnant heifers or their newborn calves.

淡路島における牛病原性ウイルスに対する抗体保有状況とその防疫対策について

In Awaji Island, Hyogo Prefecture, where about 15, 000 dairy cows and about 8, 000 adult beef cattle are raised, an antibody survey was conducted on cattle to clarify the infiltration of bovine adenovirus type 7 (Ad-7), bovine viral diarrhea virus (BVD), bovine infectiousrhinotracheitis virus (IBR), and parainfluenza type 3 virus (PI-3).In addition, calvesreared collectively were inoculated with attenuated live virus vaccines for the control of Ad-7, BVD, and PI-3. As a result, the incidence of these infections was significantly lowerin them than in unvaccinated calves.

Immunity to Dictyocaulus viviparus in Calves: III. Vaccination with Larvae Attenuated by Triethylene Melamine (TEM) or X-irradiation and Protection against Field Challenge

Calves vaccinated with D. viviparus larvae either with triethylene melamine (TEM) or by X-irradiation were exposed together with unvaccinated calves to a heavily infected pasture. Severe clinical disease occurred in the unvaccinated calves resulting in 3 fatalities out of 8 calves. Vaccinated calves withstood the challenge showing moderate clinical signs with lower respiratory rates, minimal faecal larval excretion and increased body weight gains compared with unvaccinated controls. Both types of vaccine produced similar responses.

Effect of vaccination against bovine myxovirus parainfluenza-3 before weaning and at the time of weaning on the natural history of respiratory disease in beef calves.

Earlier reports have described acute respiratory disease in native beef calves after weaning and attempts at prevention by inactivated bovine parainfluenza-3 (SF-4) tissue culture vaccines with and without an adjuvant (1, 2). The present report consists of a comparison of the effects of one and two doses of SF -4 adjuvant vaccine• in vaccinated and unvaccinated calves. Preparation of the vaccine was described previously (2).