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.
Cows and Bulls 4-6 weeks Prior to Breeding. 1. Viral respiratory vaccine (IBR, BVD, PI3, BRSV) with Campylobacter fetus (Vibriosis) and 5-way Leptospirosis-Fetal Protection (FP) product preferred. If the cow is pregnant at the time of vaccination, use a killed vaccine product to reduce the risk of accidental abortion.ertain modified live vaccines can be used in pregnant animals but only if used strictly according to label directions. 2. 7 way Clostridial (Blackleg)-necessary if under 2 years of age. Optional after that depending on the exposure risk of the herd. 3. Deworm-perform at least twice per year (spring and summer).