This study was conducted to evaluate the effects of supplementation with different levels of mineral-vitamin supplement (MVS) on performance and health of fattening lambs. Thirty-nine fattening male Ghezel× Afshar lambs (averaging body weight 31.02 ± 3.46 kg) were used in a completely randomized design for a period of 84 days. Treatments consisted of 0 (CON), 15 (MVS15), or 30 (MVS30) g/day ofMVS mixed into the concentrate. The results showed that inclusion ofMVS in the ration linearly enhanced body weight (BW) on day 29 (P < 0.002), 45 (P = 0.05), and 70 (P < 0.002). Dry matter intake (DMI) was increased linearly (P < 0.02) and quadratically (P < 0.001) with increasing supplement between days 58 and 70. OverallDMI tended (P = 0.1) to be greater for theMVS 30 treatment. Total average daily gain (ADG), ADG between days 16 and 29, days 58 and 70, total gain: feed ratio, gain: feed ratio between days 16–29 and days 58–70 linearly increased with increasing amount of MVS in the ration (P < 0.01). The days with loose fecal scores were not affected by treatments (P > 0.05). There was a linear and quadratic (P < 0.01) effect on serum Ca concentration. Phosphorus concentration tended to quadratically increase (P = 0.06) with MVS. Blood serum Zn increased linearly (P = 0.01) with increasing level of MVS. Collectively, the results showed that, under the conditions of the current experiment, MVS addition to ration improved performance of fattening lambs.
