Specific Gravity of Eggs in Relation to Egg Weight and Time of Oviposition

Abstract

Two experiments were conducted to determine the influence of time of oviposition and egg weight on egg specific gravity. Six hundred hens were used in experiment 1. Eggs were collected at 11:00 a.m., 1:00 p.m., 4:00 p.m., and 8:00 p.m. on Tuesdays for three consecutive weeks. In experiment 2, 1400 hens were used. Eggs were collected at 8:00 a.m., 10:00 a.m., 12:00 noon, 1:00 p.m., 2:00 p.m., 4:00 p.m., 6:00 p.m., and 8:00 p.m., on the one day of collection. Individual egg weights and specific gravity were determined on all eggs collected except those laid between 11:00 a.m. and 1:00 p.m. in experiment 1. Production records were used to determine the position of each egg in the sequence.The results indicated that time of oviposition was related to specific gravity and egg weight. Eggs laid in the afternoon weighed less and had a higher specific gravity than did eggs laid in the morning. The same was true regardless of the position of the egg in a sequence. In general, the later in the afternoon the egg was laid the greater the specific gravity. However, since egg weight did not continue to decrease in the afternoon as shell quality increased, it is not believed that egg weight was responsible for the change in specific gravity observed.