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.
The Centers for Disease Control and Prevention (CDC) recommends 2 doses of quadrivalent meningococcal conjugate vaccine for adolescents 11 through 18 years of age. The first dose should be given at 11 or 12 years of age, followed by a booster dose at age 16. If the first dose is given at 13 through 15 years of age, the booster should be given at 16 through 18 years of age.