EFFECTS OF STRAIN AND REARING DIETARY REGIMENS ON BROWN-EGG PULLET GROWTH AND STRAIN, REARING DIETARY REGIMENS, DENSITY, AND FEEDER SPACE EFFECTS ON SUBSEQUENT LAYING PERFORMANCE

The objective of this experiment was to compare the growth and develop ment of two brown-egg strains when grown on three different dietary re gimens, i.e., a ''normal'' step-down protein (SDP) regimen, a step-up protein regimen with a low energy starter (SUPLES), and a step-up prot ein regimen with a high energy starter (SUPHES). The SUPLES and SUPHES feeding regimens resulted in significantly lower BW and feed conversi on, shorter sternum length, and lower tibial breaking strength than th e SDP regimen. The weights of the liver, spleen, and fat pad were not different among the three regimens. The high energy starter in the SUP HES regimen significantly reduced FC below that obtained with the SUPL ES program. The SUPHES regimen significantly reduced total feed cost c ompared with the other two feeding regimens. Both step-up protein regi mens reduced total protein, energy, Ca, P, lysine, and sulfur amino ac id consumption. Because tibial breaking strength was also reduced by t he step-up protein regimens, the data suggest that the levels of dieta ry Ca and P should be increased with these programs to compensate for the reduced consumption associated with them.