Title: The Effect of Pen Floor-Type, Environmental Temperature, and Dietary Calcium Source on the Reproductive Performance and Blood Calcium of Medium White Turkeys
Abstract: This experiment was designed to study the effect of: 1) environmental temperatures of 13, 21, and 28 C, 2) laying cages vs. litter floors, and 3) limestone flour vs. oyster shell flour on the reproductive performance and blood calcium levels of turkeys. Feed consumption was significantly reduced as the environmental temperatures increased. No significant differences were obtained in egg production, settable eggs, egg weight, fertility, hatchability, or body weight within the range of pen temperatures studied. Post-lay whole blood and plasma calcium levels were lower in females held at 28 C. The difference in egg production among females in cages and on litter floors was not significant. Females in cages produced a lower percentage of settable eggs than those on litter floors and had lower post-lay total plasma calcium, whole blood calcium, and hatchability. Fertility of the caged hens and of those on litter floors was 77.0 vs. 83.3%, respectively. A sample of eggs was broken out and examined macroscopically. Results indicated a reduction in true fertility due to the cage environment. Feed consumption and body weights were similar for both pen types. Oyster shell substitution for limestone yielded better shell quality as determined by the percentage of settable eggs and by egg shell breaking strength. However, first-order interactions indicated that the effects were somewhat dependent on the temperature-floor treatment combination. No differences were found in blood calcium levels between the two calcium sources. These results showed that the reproductive potential of the egg production lines of turkeys utilized in the present study was not adversely affected by environmental temperatures as high as 28 C and that litter pens resulted in optimum reproductive performance.