Effects of Gender and Dietary Ionophores on Growth Performance and Carcass Characteristics in Moghani Lambs

An experiment was carried to evaluate the effects of gender and two dietary ionophores on growth perform-ance and slaughter characteristics in Moghani sheep. A total of 30 Moghani lambs (15 males and 15 fe-males) were distributed randomly into 30 individual cages. Each gender group consisted of 5 animals and fed with a basal diet with no supplement, the same basal diet plus 25 mg/kg monensin (MON) or 25 mg/kg lasalocid (LAS). The lambs were weighed and slaughtered after a feeding period of 134 days and carcass parameters were determined. Average slaughter weight (SW) was significantly influenced by gender (48.9 kg for females vs. 51.4 kg for males) (P 0.01) but not by diet type. Neither gender nor ionophore supple-mentations affect average daily gain (ADG) (P 0.05). Lambs fed MON had the lowest feed intake (FI) and feed conversion ratio (FCR) which significantly differed from those of the lambs fed the other two diets. Females had a significantly higher average internal fat compared with their male counterparts (P 0.01). In regard to fat-tail weight, significant decreasing was observed in ionophore groups as compared to control group (P 0.05). Males exhibited higher growth performance with heavier offals and carcass cuts including valuable cuts than in females. Dietary MON could be used as a potent feed additive improving feed effi-ciency and reducing internal fat and offals proportions in Moghani lambs.