how b12 injections are given to self-inject intramuscular vitamin - Overview Best Vitamin B12 Injection Sites:

It should not be prescribed concurrently with monoamine oxidase inhibitors (MAOIs) or other medications that significantly alter serotonin pathways due to the risk of serotonin syndrome

Sikiric P, et al

"Maintain cleanliness and avoid administration during wet or dusty conditions." Sheep and cattle can also be exposed to sub-clinical mineral deficiencies if they cannot meet their nutritional requirements from consumed feed during critical stages of the production cycle, such as before joining, lambing/calving or weaning

A 2022 UK study found that of those with B12 deficiency, pernicious anaemia was the underlying diagnosis in nearly half of the cases, making it a major cause