Correlations of the feeding behavior of lambs fed diets containing pearl millet silage with addition of urea

Abstract

The aim of this study was to evaluate correlations among the feeding behavior, intake, in vitro digestibility and production parameters of feedlot-finished lambs. Thirty-two male uncastrated mixed-breed lambs with an average initial live weight of 17.39 ± 2.16 kg were distributed into four treatments (diets) with eight replicates (animals) each, as a function of their weight, in a completely randomized block design. Diets were composed of pearl millet silage with addition of levels of urea (0, 2, 4, and 6%, DM basis), ground corn, soybean meal, and a mineral mixture. The experimental period was 62 days, consisting of 10 days of adaptation and 52 days of data collection. Positive correlations were observed (P < 0.05) for rumination time and feeding efficiency in dry matter with the intakes of dry matter (DM), crude protein (CP), ether extract (EE), neutral detergent fiber (NDF), organic matter (OM), and non-fibrous carbohydrates (NFC). Negative correlations were detected (P < 0.05) between rumination efficiency in NDF and the intakes of DM, EE, NDF, OM, and NFC. Correlations were negative (P < 0.05) between the number of chews per cud and the digestibilities of DM, NDF, NFC, and TDN. The number of chews per day was negatively correlated (P < 0.05) with the digestibility of NDF and with TDN. Rumination time had a positive correlation (P < 0.05) with average daily gain (ADG) and feed efficiency (FE). Feeding efficiency in DM was positively correlated (P < 0.05) with ADG and FE, whereas rumination efficiency in NDF was negatively correlated with ADG and positively with feed conversion. The increase in feeding efficiency for dry matter generated positive effects on nutrient intake, weight gain, and feed efficiency of the lambs fed diets containing pearl millet silage with addition of urea.