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Biomedical subjects

O C Straub

Publications and source records attributed to O C Straub.

At least 55 records · Page 3Linked to original sources
PubMed1980

Some observations on the epidemiology of bovine leucosis virus infection in a large dairy herd.

Bovine leucosis infection rates were calculated for two years in a naturally infected dairy herd in which serologically positive animals were not preferentially culled. Transmission of infection was found to occur mainly during the winter housing period. No variation in susceptibility to infection with age was found and young animals did not show a prolonged time from infection to sero-conversion.

Age Factors↗
PubMed1978

Diagnosis of enzootic bovine leukosis: a comparison of haematological and immunodiffusion tests.

A total of 657 cattle from three different herds were tested for the presence of specific antibodies against EBL antigens by means of the immunodiffusion test and the results compared with the classification according to the lymphocyte counts. All animals with pathologically raised lymphocyte counts showed a positive immunodiffusion test reaction. In the majority of these both antigens, 'p24' and 'gp', gave positive results; in a smaller number antibodies against the gp antigen only were detected, but never against the p24 antigen only. It is concluded that for field testing programmes the use of the gp antigen is sufficient. In future experiments, however, both antigens should be employed, because the lack of one of them might perhaps prove to be correlated with the future course of the disease. The absence of specific antibodies, together with a normal number of lymphocytes, in young animals should, however, not lead to the conclusion that they are free of the disease.

Animals↗
PubMed1978

Horizontal transmission studies on enzootic bovine leukosis.

Four groups of sero-negative cattle were brought into contact for various periods with either sero-positive and antigen-negative or sero- as well as antigen-positive animals. A seroconversion as evidence of transmission was only detected in animals that had been in contact with sero- and antigen-positive cattle. Shortest period of contact for those was 2 months after which a seroconversion was found. A distinct elevation of the number of lymphocytes was only detected in two animals which had been transported shortly after evidence of the seroconversion had occured.

Animals↗
PubMed1978

Preliminary results of a new sanitation program for the eradication of enzootic bovine leukosis.

The program under discussion is based on results obtained during transmission studies in which specific antibodies were detected in the immunodiffusion test earlier than antigen in peripheral blood leukocytes. Furthermore, it could be demonstrated that seroconversion does not seem to occur later than 3 months after transmission of the infectious agent. The results obtained in 11 herds are presented. The program is as follows: when the result of the immunodiffusion test becomes available all positive animals above 6 months of age are immediately removed from the herd. The remaining animals are checked at intervals of 3 months and sero-positives are always instantly removed. In pursuing the program a number of herds have obviously reachend 2 years old.

Animals↗
PubMed1978

The immunoglobulin composition of colostrum and the persistence of acquired immunoglobulins and specific antibodies in the calf.

The absolute amounts of immunoglobulins contained in twenty-five samples of colostrum were determined. It was found that the quality of the colostrum is approximately the same for the first nine hours following parturition. The secretion of a cow following an abortion, however, does not have the quality of colostrum and should therefore not be saved to feed newborn calves. Detailed studies concerning the transfer of colostral antibodies to the newborn showed that ideally two liters of colostrum should be given within the first twelve hours. If the calf is derived from a heifer, a young cow or from a newly introduced animal it should receive 50% of its colostrum from an older cow of the herd. The colostrum can be kept in a frozen state for 15 years without losing too much of its original quality. The amounts of immunoglobulins and specific antibodies (against infectious Bovine Rhinotracheitis and Parainfluenza-3) transferred were remarkably high and most likely due to those infections the dams had suffered from. It is proposed that programs should be introduced whereby dams are regularly vaccinated during the late gestation period. The vaccines used and their composition have to depend on the diseases prevalent in the individual countries and regions.

Animals↗