The mineral composition of hay and silage grown in Scotland in relation to the A.R.C. standards for the mineral requirements of dairy cattle

Abstract
Summary Samples of hays (132) and silages (146) were analysed for calcium, phosphorus, magnesium, copper and manganese. Assessments were made of their ability to supply minerals to cattle in accordance with the A.R.C. (1965) minimal requirements. The concentrations of all these minerals were greater in silage than in hay. The proportions of the hay samples which in 20 lb of dry matter, provided inadequate amounts of minerals to maintain cattle of 1100 lb live weight were 4% (Ca), 98% (P),21% (Mg), 90% (Cu) and 39% (Mn). In a similar manner 15 lb of silage dry matter proved inadequate to a comparable degree. For the samples examined 4% (Ca), 99% (P), 19% (Mg), 62% (Cu) and 15% (Mn) did not meet the proposed standards. Data are presented to indicate the amounts by which a variety of cattle diets based on hay and silage fail to meet the A.R.C. (1965) minimal requirements in respect of calcium and phosphorus intakes for milk yields up to 4 gal.