Environment, incidence, aetiology, epizootiology and immunoprophylaxis of soil-borne diseases in north-east Mexico.

Within the framework of an extensive research programme, the socio-economic and environmental conditions which influence the emergence of soil-borne diseases in north-eastern Mexico were analysed. Furthermore, specimens collected from carcasses in the field were bacteriologically examined and the causal organisms of soil-borne diseases differentiated by means of gas chromatographic analysis of their metabolic products and the long-chained fatty acids contained in the cell. With experimental clostridial vaccines prepared with the Goettingen Bioreactor Technique, trials to protect cattle and guinea-pigs against gas gangrene were carried out. It was found that the farm structure and the dry climate as well as the specific soil conditions and plant cover favour the emergence of soil-borne diseases. Causal organisms B. anthracis, C. perfringens, C. sordellii, C. haemolyticum, C. chauvoei/septicum, C. novyi A, C. botulinum and site-specific field strains of clostridia were detected. Experimental site-specific vaccines proved to be highly efficient in protecting cattle and guinea pigs.

[The virulence of L. leucocephala for goats in northeastern Mexico]. / Untersuchungen zur Giftigkeit von L. leucocephala für Ziegen im Nord-Osten Mexikos.

When fed 100% Leucaena during a period of 45 days goats with experience in L.-fodder took significantly (P less than 0.05) more dry matter (50.01 g/kg0.75) than those without or only possible experience (44.40 g/kg0.75 and 45.63 g/kg0.75). The uptake of Mimosine from animals with Mimosine experience (1.14 g/kg0.75) has also been significantly higher (P less than 0.05) than from two other groups with non or only possible experience (0.93 g/kg0.75 and 0.92 g/kg0.75). The Serum-Thyroxin level (T4) of the control group (5.12 micrograms/100 ml) and of the group with Leucaena experience (4.65 micrograms/100 ml) has been significantly higher (P less than 0.05) during the entire trial period than that of the two other trial groups (3.9 micrograms/100 ml). Hair-loss, reduced fodder uptake, increased salivation, excitation, ataxia of hind legs, vomit of fodder and uncoordinated chewing of fodder have been observed in animals without or only possible Leucaena experience. Three animals of those died through direct or indirect influence of the poisoning. Swollen buccal papillae, ulceration and necrosis of the oesophagus and haemorrhagic lesions in the reticulum and rumen have been observed in two of the dead animals.