Deficiencies can occur due to low feed intakes or more commonly as a result of vitamin breakdown by oxidation during the processing and storage of grains and hays
While the liver has substantial storage capacity, supraphysiological doses (such as from injections) are largely excreted in the urine
When you lack B12, your red blood cells become malformed, and the oxygen delivery is compromised, making you feel tired
In many cases, its fine to continue a multivitamin while on B-Complex injections, but it may not be necessary
If the gut cannot absorb B12 for example, pernicious anemia or after certain gastric surgeries injections are often necessary
Vitamin B12 supports the nervous system by maintaining myelin, which is the protective coating around nerves