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Objective: To evaluate the application of ultrasonography for studying normal reproductive system in laying hens and compare three ultrasonographic approaches. Design: Observational study. Animals: Seventeen Hy-Line laying hens, aged 56 weeks.
Procedure: Ultrasonography was performed daily in each
bird for 21 days at standing (St), lateral (Lt) and dorsal recumbent (Do) positions. Number of follicle and yolks, yolk-
albumin diameter, albumin thickness, and egg dimension were measured, as well.
Statistical analysis: One- way analysis of variance and Pearson
correlation.
Results: Follicle, yolk, yolk - albumin, albumin and egg were detectable structures in the scans. There were no significant differences in the number of ovarian follicle and yolk, and diameter of yolk - albumin and albumin thickness among the
above- mentioned positions. The mean number of follicle
and yolk were 3.12±0.89 and 2.68+0.51, respectively. The mean
diameter of yolk -albumin and albumin thickness were 4.45±0.15
cm and 0.29±0.04 mm, respectively. Correlation coefficient of small and large diameters between scanned and laid eggs were
0.48, 0.583, 0.456, 0.589, 0.605 and 0.522 in standing, lateral and
dorsal recumbent positions, respectively. Clinical implications: Since no significant difference was
detected in dimension of studied structures between three
examined approaches, birds felt comfort and also achievement
of normal positions of reproductive system at standing position, it can be considered as the superior approach in comparison with two other ones. J. Fac. Vet. Med. Univ. Tehran. 59, 1: 23-
27,2004.