Effect of Zinc and Iodine Supplementation on Feed Utilization and Growth in Crossbred Heifers

An experiment was conducted on 18 growing crossbred (SxJ) heifers (19–25 m, 100–209 kg B. W), to assess the effect of zinc and iodine supplementation on nutrient utilization and body weight gains. The heifers were divided into three equal groups and a basal roughage ration (iodine 0.178 ppm and zinc 31.2 ppm) was fed ad libitum and supplemented with a ready made concentrate mixture. Animals in the first group received no mineral supplement in the concentrate mixture. The second group received iodine (as KI) @ 1 g/100 kg and third group received concentrate mixture containing KI @ 1 g/100 kg concentrate mixture and zinc as (zinc sulphate) @ 10 g/100 kg concentrate mixture. Total as well as digestible intake of DM, OM, CP, EE, NDF and ADF expressed as kg/100 kg B.W. were significantly (P<0.05) higher in zinc+iodine supplemented group. The digestibility of DM, OM, CP, EEand GEdid not differ among the treatments. However, digestibility of NDF and XADF increased signifcantly (P<0.05) due to zinc and iodine supplementation. Intake and retention of N and Ca was non significantly higher in iodine and zinc supplemented group (P<0.05). The intake, excretion, retention (g/day) of zinc, body weight gains and average daily weight gain of the heifers in zinc and iodine supplemented group increased significantly (P<0.05). The results indicated that the supplementation of zinc and iodine to normal basal ration of roughage fed to growing heifers proved beneficial in terms of higher intake of nutrients, improved fibre digestibility and higher growth rates.