GROWTH AND MODIFICATION OF DIGESTION IN LAMBS FED DIETS CONTAINING CEMENT KILN DUST

Three experiments were conducted to determine (1) the effect of cement kiln dust (CKD) on the growth of lambs fed high- or low-roughage diets, (2) the effect of pelleting on lamb diets which contain CKD, and (3) the effect of different levels of dietary CKD on lamb performance. In exp. 1, lambs were fed complete pelleted diets containing 15 or 45% ground timothy hay with either 0 or 3% CKD. There were no differences in weight gain due to CKD addition. The feed consumed was greater for the high roughage-CKD group (P < 0.05). Feed:gain ratios were greater for the high-roughage groups (P < 0.01). The pH of gastrointestinal tract contents showed an increase due to CKD only in the cecum and colon. The carbohydrate level in the colon of lambs fed the low-roughage rations was lower (P < 0.05) with added CKD. In exp. 2, lambs were fed CKD diets in mash and pelleted form, a complete pelleted CKD diet (including hay) or a mash CKD-free control. All diets except the complete pelleted-CKD diet were fed with hay, ad libitum. Lambs fed the pelleted CKD diet plus hay grew faster than the control group (P < 0.05) with growth in the other groups not different from either extreme. In exp. 3, lambs were fed similar diets containing 0, 1, 2 or 3% CKD. Growth was not different for any of the groups. Fecal pH was elevated in two of the CKD groups. Analysis of feces showed no difference in nitrogen, soluble carbohydrate, ADF or NDF as a percent of organic matter. Fecal ash increased with increasing level of CKD (P < 0.01). Key words: Lamb, cement kiln dust, growth rate, digesta pH