Anthrax vaccine associated deaths in miniature horses

During a widespread anthrax outbreak in Canada, miniature horses were vaccinated using a live spore anthrax vaccine. Several of these horses died from an apparent immune-mediated vasculitis temporally associated with this vaccination. During the course of the outbreak, other miniature horses from different regions with a similar vaccination history, clinical signs, and necropsy findings were found.     

The effect of some pre-treatments on proteolysis during the ensiling of herbage

Two experiments were carried out to examine the nitrogenous changes occurring in herbage during harvesting and ensiling. In the first, ryegrass-clover was wilted rapidly in the laboratory (6 h) and in the field under good (48 h) and poor (48 h and 144 h) weather conditions. Protein breakdown and ammonia formation were negligible in herbage wilted rapidly and it was only when the crop was exposed to a prolonged wilt in humid conditions that appreciable proteolysis occurred. In the second experiment ryegrass-clover was ensiled in laboratory silos after treatment with varying levels of formic and sulphuric acids. An additional treatment included herbage inoculated with a mixture of lactic acid bacteria and glucose. The silos were opened after 4 and 50 d and samples were analysed for protein-N, ammonia-N, water-soluble carbohydrates and organic acids. There was a high negative correlation between level of addition of either acid and the degree of proteolysis and deamination. Even at the highest levels of formic acid (7·7 g per kg) and sulphuric acid (4·0 g per kg) additions, however, about 45% of the original herbage protein was degraded after 50 d in the silo. The inoculum treatment was also effective in reducing proteolysis, the effect after 50 d being comparable with formic acid applied at a rate of 4·1 g per kg.     

Population and classification of intrapopulation units of helminths

The study of the population problems revealed that the population is an elementary evolution unit of a species with biparental way of reproduction. This is a general theoretical definition which the author elaborated in detail for the helminths. With regard to the complicated intraspecific structure of these parasites also the classification of intrapopulation helminth units is proposed.     

Dalapon resistance at an early seedling stage in Lolium perenne

The inhibitory effect of the herbicide dalapon on germination and shoot elongation was evaluated in two perennial ryegrass cultivars, Melino RvP and Cropper. These cultivars had been shown to be dalapon resistant and susceptible, respectively, in a previous comparison of 14-week-old plants. Dalapon (10^-2 and 10^-3 m) significantly reduced rates of germination and shoot elongation to the same extent in both cultivars. It is suggested that the effects of dalapon on germination and shoot elongation during the first 9 days of development are not indicative of levels of resistance in more mature plants.     

The influence of the herbicide methabenzthiazuron on the synthesis of plastidic lipids in Hordeum vulgare seedlings

The herbicide methabenzthiazuron, and inhibitor of the Hill reaction, was applied to Hordeum seeds at the time of sowing, and the greening process under continuous Fluora light was investigated to the age of 13 days. Chlorophyll and xanthophyll contents were increased by methabenzthiazuron relative to the controls, with degrading ratios of chlorophyll a/chlorophyll b and rising xanthophyll/carotene values. The enhanced ratios of chlorophyll a to lipoquinones, like the absolute values, indicate an inhibition of the lipoquinones. These metabolic alterations are similar to those found in shade-adapted leaves. It is suggested, therefore, that inhibition of the photosynthetic electron transport, like deficiency in light of shade leaves, is compensated by metabolic reactions leading to a greater amount of photosystem II with an enhanced accumulation of the light-trapping chlorophylls and carotenoids.