Timothy mineral concentration and derived indices related to cattle metabolic disorders: A review

Abstract

Timothy (Phleum pratense L.) is grown in several countries, mainly for livestock forage. The nutritive value and dry matter (DM) yield of timothy is well established but less information is available on mineral concentration and related indices, like the dietary cation-anion difference (DCAD) and the grass tetany (GT) index. These indices predict the risk of a forage diet to cause metabolic disorders, i.e., milk fever for DCAD and grass tetany for the GT index. Improving our knowledge of factors affecting timothy mineral concentration is important for livestock production. This review paper compares timothy with other common cool-season grasses for mineral concentrations, DCAD, and GT index. Also assessed are variations in timothy mineral concentration affected by harvest and fertilization management, soil mineral availability, and environmental conditions. These results demonstrate the high potential for improvement and use of timothy forage to decrease the incidence of metabolic disorders within the dairy industry. Key words: Milk fever, grass tetany, dietary cation-anion difference, grass tetany index, forage, cool-season grasses