Effects of dietary replacement of maize grain with popcorn waste products on nutrient digestibility and performance by lambs

A study was conducted to evaluate the effects of dietary replacement of maize with popcorn waste (PW) on the intake, nutrient digestibility and growth performance of lambs. Diets replacing 0, 25, 50, 75 and 100% maize with PW were formulated and fed ad libitum to 40 South African Mutton Merino lambs (25.0 ± 0.45 kg live-weight). The diets had similar intake and nutrient digestibility of dry matter (DM), organic matter (OM) and neutral detergent fibre (NDF). Lambs fed the 25 and 50% PW diets had higher intakes of crude protein (CP), metabolizable energy and ether extract compared to the other diets. Growth rate was highest (226 g/d) on the 25% diet and lowest (109 g/d) on the 75% PW diet. Best feed conversion ratio (FCR), of 5.1 (kg feed/kg live weight) was obtained with the 0% PW diet. Improved digestibility of CP and EE occurred in the 25 and 75% PW diets. Higher intake of nitrogen (N) and N retention were obtained in the 25 and 50% PW diets. Dietary replacement of >75% of maize resulted in poor animal performance (ADG < 150 g/d and FCR >7.00). It was concluded that PW can replace up to 50% of the maize in diets for growing lambs.