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.
Early weaning for the purpose of improving fertility of first calf heifers can be done when the calves are 35 to 60 days of age. Clemson University studies have shown that 81 percent of the heifers whose calves were weaned at 56 days of age calved within the first 30 days of the subsequent calving season.arly weaning for the purpose of improving fertility of first calf heifers can be done when the calves are 35 to 60 days of age. Clemson University studies have shown that 81 percent of the heifers whose calves were weaned at 56 days of age calved within the first 30 days of the subsequent calving season.