In geography and fluvial geomorphology, a thalweg or talweg (/ËtÉËlvÉÉ¡/) is the line of lowest elevation within a valley or watercourse. Under international law, thalwegs can acquire special significance because disputed river borders are often deemed to run along the river's thalweg. 1 Etymology.
However, when they are 3 to 4 months old, they become susceptible to the disease, so all calves should be vaccinated for blackleg by 4 months of age. A revaccination 3 to 6 weeks later according to product label directions is necessary to provide the best protec-tion.lackleg seldom affects cattle older than 2 years of age, most likely due to immunity induced by vaccines or natural exposure. However, sporadic cases do occur in cattle older than 2 years and are often associated with the reuse of needles for multiple injections.
However, the OSU-Noble Foundation research demonstrated otherwise. The scientists vaccinated calves at 67 days of age and re-vaccinated them at weaning â 190 days â and then compared those animals with others vaccinated at 167 days of age and given a second vaccine at 190 days, at the time of weaning.owever, the OSU-Noble Foundation research demonstrated otherwise. The scientists vaccinated calves at 67 days of age and re-vaccinated them at weaning â 190 days â and then compared those animals with others vaccinated at 167 days of age and given a second vaccine at 190 days, at the time of weaning.