I.E. Selman

Serum immune globulin concentrations of calves left with their dams for the first two days of life

Abstract The serum immune globulin concentrations of 30 two-day-old calves were estimated using the zinc sulphate turbidity test. These calves had been born in loose boxes and left with their dams for the first two days of life. Dairy calves suckling their dams before eight hours post partum almost always attained high serum immune globulin concentrations, whereas dairy calves not suckling before this time were invariably deficient in serum immune globulins. Moreover, in the fifteen dairy calves which did suckle during the first eight hours of life, a significant negative correlation was found between the time of first suckling and the 48-hour serum immune globulin concentration. The beef calves in the series gave far less consistent results. No difference was found between the serum immune globulin concentrations of those dairy calves born during the summer and those born during the winter.

Reactivation and shedding of bovine herpesvirus 1 following Dictyocaulus viviparus infection

Three groups of 4 bullocks which had recovered from infectious bovine rhinotracheitis (IBR) were infected 5 months later with Dictyocaulus viviparus larvae. Bovine herpesvirus 1 was recovered from days 7 to 21 post-infection from the nasal secretions of the group given 50 larvae per kilogram and on one occasion from those given 1000 larvae per animal (less than 5 L3 per kg). Virus was not isolated from the animals given 1000 irradiated larvae. Typical clinical signs and lesions of IBR developed in the group from which the virus was isolated regularly.

Fog fever in cattle: cytology of the hyperplastic alveolar epithelium.

Abstract Alveolar epithelial hyperplasia is a prominent pulmonary lesion in fog fever, which is an acute respiratory distress syndrome of adult cattle. The hyperplastic cells are cuboidal in shape, rest on a basement membrane, form tight cell junctions with their neighbours, possess microvilli on their free surface, and contain lamellated, irregularly electron-dense inclusion bodies in their cytoplasm. These features enable the cells to be characterized as type 2 pneumonocytes.

The prevalence of serum precipitating antibody to Aspergillus fumigatus in adult cattle in Britain

The prevalence of precipitating antibody to A. fumigatus in 3509 sera from adult cattle in 44 herds was 25 per cent. Only 19 per cent of sera from grazing or recently housed animals were positive compared with 30 per cent of those taken towards the end of the winter. Mouldy hay was the most likely source of A. fumigatus antigens although a positive correlation between the prevalence of precipitins and either the mouldiness of the hay or the frequency of coughing in the springtime was not established. However, there was a positive correlation between the age of cattle sampled and the prevalence of antibodies. Mycotic abortion had been confirmed in only one of 6 herds in which more than 80 per cent of the cows were seropositive and so it can be inferred that the presence of serum precipitating antibody is of very little value in the diagnosis of mycotic abortion resulting from A. fumigatus infection.

Fog fever: Provocation tests with Dictyocaulus viviparus

Abstract There have been many suggestions that fog fever of cattle is the result of a hypersensitivity to Dictyocaulus viviparus . However, when 7 adult cattle that had recovered from fog fever were challenged orally with 30 000 third-stage larvae of D. viviparus , the acute respiratory signs did not recur. Pulmonary lesions comparable to those of reinfection husk and unlike those of fog fever were found at post mortem examination of the 7 animals, one month after challenge. It is concluded that there is no evidence that fog fever occurs as the result of a hypersensitivity reaction in sensitized cattle to oral reinfection with d. viviparus larvae.