Evaluation of an alfalfa silage-corn silage roughage feeding program for raising dairy heifers

One hundred and ninety-seven dairy heifers, which included a Holstein line, an Ayrshire line, and a reciprocal cross line, were assigned randomly to two forage treatments at 57 days of age. Forages fed to control heifers consisted of 40% grass-legume hay, 20% wilted grass silage, and 40% corn silage (dry matter). The second, or silage group, was fed a dry matter mixture of 40% corn silage and 60% direct cut alfalfa silage, formic acid treated. Both groups of heifers were fed the same quantity of calf starter and calf grower rations. In general, heifer weight and size were greater with the all-silage forage. At 350 and 574 days of age, heifers on the all-silage ration were heavier than their controls. Heifers fed the all-silage ration had greater heart girths and wither heights. Reproductive performance, as measured by the number of services per conception, was not significantly different in the two treatment group. There were no health problems that could be attributed directly to dietary treatment. Dairy heifers were reared successfully on a forage mixture of corn silage and formic acid treated alfalfa silage when additional concentrate was fed during the 1st yr.