We use calcium specifications from decades-old research, so we need to make sure those numbers are still valid.
Calcium is rarely considered to be a limiting nutrient in pig feeds because it is abundant and cheap. Limestone and calcium carbonate – the two most common sources of calcium – are readily available, and at competitive prices. But there are cases where calcium deficiency or toxicity, or under- and over-supplementation, can occur, causing considerable problems. Despite its abundance and low price, calcium cannot be used without caution and, as it happens, this is the case as it is invariably being used as a common carrier for many products.