Feeding Value of Different Grades of Alfalfa Hay for Growing Dairy Heifers

Alfalfa is the principal legume hay used on dairy farms in the United States, supplying about 10 per cent of the total feed nutrients used by dairy cows.A survey of the quality of alfalfa hay produced in New Jersey during 1948, 1949 and 1950 (5), indicated that on an average 14 per cent graded U. S. no. 1, 22 per cent U. S. no. 2 Leafy, 27 per cent U. S. no. 2, 9 per cent U. S. no. 3 Leafy, 15 per cent U. S. no. 3, and 13 per cent Sample grade.These data illustrate the wide variance in the quality of alfalfa hay as graded by the published standards of the U. S. Department of Agriculture (3).Very few experimental data are available on the feeding value of the U. S. grades of alfalfa hay.Pollock and Hosterman (2) have summarized general information on hay quality in relation to production and feed value.Kelkar and Gullickson (1) fed U. S. no. 1 Extra Leafy Green Alfalfa hay and U. S. no. 3 Leafy Brown Alfalfa hay to two pairs of identical twin dairy heifers.The U. S. no.I Extra Leafy Green Alfalfa hay was more palatable, richer in digestible nutrients and carotene, and produced slightly more rapid gains in weight and in height at withers than the U. S. no. 3 Leafy Brown Alfalfa hay, but at a higher cost in nutrients per unit of gain.In order to obtain data on the relative feeding value of different grades of alfalfa hay, hays of different grades were purchased and fed to groups of growing dairy heifers in two winter-feeding experiments. EXPERI~CIENTAL PROCEDURE Experiment I~1949-50An attempt was made to obtain U. S. no. 1 and U. S. no. 3 Alfalfa hays for use in this experiment.The alfalfa hays used were obtained from farms in the same general locality in the Shenandoah Valley of Virginia.At the time the hays were obtained, selection on the basis of grade classifications was made by an official hay grader, who examined the lots before they were purchased.However, the final grade given each lot of hay was made by averaging the grade classifications given to samples taken at 10-day intervals during the time the