Comparison of direct electron microscopy and enzyme immunoassay for the detection of rotaviruses in calves, lambs, piglets and foals

Direct electron microscopy (EM) and enzyme-immunoassay (rotazyme) results for the detection of rotaviruses in 346 enteric specimens from calves, lambs, piglets and foals were compared. The rotazyme test was at least 3 times more sensitive than direct EM in diagnosing infection. Rotavirus antigen was demonstrated by rotazyme in 22% of 280 scour samples and in 27% of 66 samples from non-scouring animals. There was an association between diarrhoea and higher amounts of rotavirus antigen. This prevalence of rotaviruses detected in animals with diarrhoea highlights the significant involvement of other pathogens identified in the study including Eimeria, Cryptosporidia, Escherichia coli, Campylobacter, and other viruses.     

Seasonal variation in the components of partial resistance of seedlings of winter wheat cultivars Maris Huntsman and Maris Ranger to Septoria nodorum

Components of partial resistance of two winter wheat cultivars, Maris Huntsman and Maris Ranger, to Septoria nodorum were measured on potted seedlings exposed in the open during the spring and early summer of 1978. The number of lesions 10 days after inoculation was always greater for Maris Ranger than for Maris Huntsman but the relative differences changed during the season: about 10:1 in March, April and May, but only 3:1 in June. The time from infection to first sporulation (latent period) on Maris Ranger was always shorter, especially in March. The percentage leaf area covered by lesions at the end of the latent period was usually greater on Maris Ranger, but variation in the percentage leaf area necrotic at this time did not follow a distinct seasonal trend, nor did cultivars differ in this respect. Twice as many spores per unit area diseased were produced on Maris Ranger as on Maris Huntsman. Seasonal variation in these components could partially be interpreted in terms of the changing weather conditions to which the plants were exposed.     

The effects of caseous lymphadenitis on wool production and bodyweight in young sheep

Two hundred Merino wether hoggets were used to examine the effect of Corynebacterium pseudotuberculosis infection (caseous lymphadenitis) on wool production and bodyweight. Sheep which were challenged with C. pseudotuberculosis (artificially infected) and not vaccinated against this disease produced 0.20 kg less clean wool than unchallenged controls during the following 12 months. The incidence of sheep with lesions in the group that was vaccinated prior to challenge was 55% lower than in unvaccinated challenged sheep but their wool production was not significantly different from either the controls or the unvaccinated challenged sheep. Vaccinated sheep were also heavier than unvaccinated sheep 12 months after challenge. These results indicate that caseous lymphadenitis infection may reduce wool production.