Nucleotides are nucleic acid, and are the building blocks of DNA and RNA, so any cell that replicates (which is pretty much all cells!) will replicate DNA and RNA to do so – i.e. repair from an injury/improving the villi that line the digestive tract to aid nutrient absorption/aid the repair of the laminae following laminitis – nucleotides help speed this process up.  As nucleotides will improve the production of red blood cells it also means more oxygen to working muscles = reducing lactic acid production = promoting fitness and stamina = reducing recovery rates.