Olsson’s Equine Calcium Plus provides a source of calcium & vitamin D for horses grazing high phosphorus pastures. During periods of low dietary calcium intake, calcium can be mobilised from bone to maintain normal blood calcium levels. If inadequate dietary calcium persists, the bone calcium may be replaced by fibrous tissue, which has been associated with weakened bones and a condition commonly referred to as “Big Head.” This is most often observed in horses grazing tropical grasses such as kikuyu, buffel, setaria, green panic, para grass, pangola grass, guinea grass, signal grass and purple pigeon grass. These grasses contain oxalates that bind calcium, reducing its availability for absorption, and diets high in phosphorus, such as those containing significant cereal grain, can also reduce calcium availability.