I. INTRODUCTION Historically, there has been a move from the use of a total Ca (tCa) to total P (tP) ratio system (NRC, 1950) to a tCa to inorganic P (iP) ratio (NRC, 1954), to the use of tCa to available P (aP) that appeared in the 1984 NRC. In 1950, the requirements were 1.0% tCa and 0.6% tP (1.66 tCa:tP) (NRC, 1950) and, in the 1954 NRC, the qualification was made giving importance to the a...
Good, thought provoking article. We shall estimate the digestibility of calcium from Calcium oxide, carbonate, sulphate, propionate etc. Their availability and cost factors. Thanks
Hello Roselina, very interesting and challenging paper for all those involved in animal feeding and nutrition, just like me. Let me make a couple of comments so you can please answer them if possible. You mention digestibilities of 34,1% and 67,9% for Ca for limestone and MCP in recent work at Maryland; but yet, correct me if I am wrong, on a weight to weight basis, we still provide more dCa with limestone don´t we?, assuming a Ca content of 38,6% and 17,8% for limestone and MCP respectively. The second comment would be how possible is to get digestibilities of Ca to be 62,7% (Tamim et al., 2004) vs just 34,1% in the recent Maryland work?. Many thanks for your always clear and good explanations. I have had the chance of listening lectures of yours a couple of times and always enjoyed them lots. Greetings from Madrid.