Influence of Pre-Laying Dietary Calcium upon Tibial 45 CA Uptake in 20-Week-Old Pullets

At 5, 10 and 15 weeks of age, 20 pullets were changed from a 1.30% Ca diet to one containing 0.65 or 2.60% Ca. At 19 weeks of age, half these pullets were changed to a 2.00% Ca diet. Ten pullets each were fed the 0.65% and 2.60% Ca diets from hatching to the termination of the experiment. At 20 weeks of age, all the pullets were administered 45 Ca into the crop and sacrificed 24 hours later. Changing the diet had no significant effect on 45 Ca deposition in the tibia regardless of the time the change was made as long as all the groups compared were fed the same final diets. However, the pullets fed the 0.65% Ca diet deposited more 45 Ca in their tibias than did those fed the 2.60 or 2.00% Ca diet. Adaptation to calcium fed prior to laying was not the result of altered absorption and subsequent deposition of calcium in the skeletal pool.