title: 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.
abstract: The objective of this experiment was to compare the growth and development of two brown-egg strains when grown on three different dietary regimens, i.e., a "normal" step-down protein (SDP) regimen, a step-up protein regimen with a low energy starter (SUPLES), and a step-up protein regimen with a high energy starter (SUPHES). The SUPLES and SUPHES feeding regimens resulted in significantly lower BW and feed conversion, shorter sternum length, and lower tibial breaking strength than the SDP regimen. The weights of the liver, spleen, and fat pad were not different among the three regimens. The high energy starter in the SUPHES regimen significantly reduced FC below that obtained with the SUPLES program. The SUPHES regimen significantly reduced total feed cost compared with the other two feeding regimens. Both step-up protein regimens reduced total protein, energy, Ca, P, lysine, and sulfur amino acid consumption. Because tibial breaking strength was also reduced by the step-up protein regimens, the data suggest that the levels of dietary Ca and P should be increased with these programs to compensate for the reduced consumption associated with them.
mesh_terms: D000821:Animal Feed; D000822:Animal Husbandry; D000818:Animals; D002645:Chickens / Q000235:genetics / Q000254:growth & development*; D018753:Diet, Protein-Restricted / Q000662:veterinary; D005260:Female; D006799:Housing, Animal; D010058:Oviposition / Q000502:physiology; D012098:Reproduction / Q000502:physiology; D013045:Species Specificity