Improvement of reproductive efficiency in the ostrich : characterization of late embryo mortality /
| Main Author: | |
|---|---|
| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1992.
|
| Subjects: | |
| Online Access: | Link to OAKTrust copy |
| Abstract: | This research was carried out on a commercial ostrich farm in western Oklahoma. Seasonal production of the hatchery was analyzed and observations on the 1100 eggs incubated during the 1990 season were summarized to add to the general base of reproductive data. The overall objective was to investigate the high late embryo mortality, or dead in the shell (DIS) losses. Examination of the water balance in the eggs at the end of the incubation period by measuring the percentage weight loss revealed a significant difference between eggs hatching unassisted and eggs from the DIS group (12.25% vs 10.20%). A frequency distribution of the DIS group peaked at 7% weight loss demonstrating that, although both extremes of high-and low-water-loss eggs contributed to the DIS group, the majority of the DIS embryos from this study were from low-water-loss eggs. Measurements of pore density confirmed that there was a wide variation in porosity exhibited within and between the eggs from this sample. The equatorial region had less variation than either of the polar regions and proved the most useful area for comparative sampling. Ostrich eggs hatching without assistance had greater pore density per cm^2 (23.8) than the DIS group (18.1) and thinner shells than eggs requiring assistance to hatch (1.81 vs 1.91 mm). A comparison of eggs from three flocks incubated in the same incubators demonstrated that average percentage weight loss and pore density were different among flocks, indicating that incubation conditions may need to be adjusted on a flock basis. This research demonstrated that, under conditions of forced-draft incubation and consistent temperature and humidity, ostrich eggs lose weight at a constant rate throughout the incubation period. Estimated transfer weights based on the rate of weight loss measured during the first week of incubation were highly correlated with actual transfer weights, and may provide a useful tool for identifying eggs with problem porosity during the first week of incubation. |
|---|---|
| Item Description: | Typescript (photocopy). Vita. "Major subject: Physiology of Reproduction." |
| Physical Description: | x, 91 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |