This study aims to determine the effects of alfalfa supplementation on the pre- and postweaning performance, rumen development, and feed transition in starter diet-fed lambs. Six of 66 male Hu lambs were slaughtered at the age of 10 d to serve as a control. The other 60 lambs were randomly allocated to 2 dietary treatments: milk replacer and starter pellets without (STA) or with free-choice chopped alfalfa (S-ALF). The animals were offered 300 g/d of the concentrate mixture and had free access to alfalfa after weaning at the end of wk 4 (age 38 d). The alfalfa inclusion in the S-ALF group tended to increase the starter intake before weaning, significantly increased the concentrate intake soon after weaning ( < 0.05), and increased the BW ( < 0.01) and ADG ( < 0.10) in pre- and postweaning lambs. The S-ALF group had heavier carcasses ( < 0.05), rumens ( < 0.05), reticula ( < 0.05), omasums ( < 0.10), abomasums ( < 0.05), and visceral organs ( < 0.10) than the STA lambs after weaning. Alfalfa supplementation increased ( < 0.05) the rumen papillae length and the ratio of the duodenal villus height to the crypt depth; it also decreased ( < 0.05) the concentration and molar proportion of propionate in wk 1 and 5. The STA lambs had higher ( < 0.01) blood concentrations of globulin and blood urea nitrogen and lower β-hydroxybutyrate after weaning. The STA group also had a higher incidence of feed plaque. From the above results, we infer that the free-choice addition of chopped alfalfa to starter diets is beneficial to rumen development, relieves weaning stress, and improves the performance of lambs.

In this paper, the wake structures of a cantilever beam in axial flows under the excitations of piezoelectric actuators are studied. It is assumed that the dynamic response of the cantilever beam is relatively small (i.e., linear) and the beam is modeled as an Euler-Bernoulli beam. The total force is divided into two parts: 1) the hydrodynamic loading, which changes beam’s natural frequencies and damping ratios and 2) the piezoelectric induced part, which is the excitation force. Furthermore, the hydrodynamic loading can be separated into an added mass term and a fluid damping term and they are obtained with the hydrodynamic function; the excitation force induced by the converse piezoelectric effect is calculated with Love’s control operator. In order to maximize wake generations, two specific types of piezoelectric actuators (i.e., modal actuators and segmented actuators) are used in this study. It is assumed that the mode shapes of the cantilever beam remain unchanged in fluids and the dynamic responses of the cantilever beam can be calculated by the modal expansion method. Once the dynamic responses of the cantilever beam are known, the panel method free-wake model is adopted to simulate the wake structures. In case studies, the wake structures excited by modal actuators and segmented actuators of the first four modes are compared. The effects of applied voltage and flow velocity to the wakes are also studied. Distinct wake roll-up phenomenon is observed in all simulation results. Higher applied voltage and lower flow speed make the wake easier to roll-up.