EFFECTS OF PELLETING, ROUGHAGE LEVEL, AND HORMONE IMPLANTATION ON THE UTILIZATION OF FINELY GROUND CRESTED WHEATGRASS BY GROWING LAMBS
Rations containing 50, 70, and 90% crested wheatgrass and one in which the level of crested wheatgrass was gradually reduced from 90 to 50% were fed in the ground (0.48-cm screen) and pelleted forms to wether and ewe lambs, with and without Synovex implants, in a factorially designed experiment. Pelleting increased dry matter (DM) intake, rate of gain, and feed efficiency by 15, 47, and 23%, respectively (P < 0.05). The level of roughage in the ration did not significantly affect dry matter intake, rate of gain, or feed efficiency, and there was no significant interaction between ration form and roughage level. In vitro digestible energy content of the ground rations was 2.66, 2.46, and 2.44 kcal/g DM at the 50, 70, and 90% roughage levels, respectively; the corresponding values for the pelleted rations were 2.75, 2.51, and 2.49 kcal/g DM. The implant treatment increased rate of gain and feed efficiency by 18 and 17%, respectively (P < 0.05) and this effect was not influenced by ration form, level of roughage, or sex of lamb. Dressing percentage was greater and loin area smaller (P < 0.05) at the 50% roughage level than at the 90% level. Pelleting decreased loin area of females (P < 0.05) but not of males. Dressing percentage and backfat thickness tended to be increased by pelleting but this was not significant. Synovex implants decreased dressing percentage (P < 0.05) but did not significantly affect backfat thickness or loin area.