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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Reproductive Soundness and Egg Quality in Chickens Selected for Low and High Antibody Response

Albrecht, Heather Nicole 08 September 2011 (has links)
For 36 generations, White Leghorn chickens were selected for high (HAS) or low (LAS) antibody response to sheep red blood cells. The focus of this thesis was to investigate correlated responses in reproductive soundness and egg quality resulting from that selection. Forty-five hens and 25 roosters from each antibody line were used. In hens, commencement and intensity of lay, and egg quality, were analyzed; in both sexes, length of fertility was considered. Hens and roosters were mated to an intercross line to avoid confounding selection with sex effects. The LAS line was more reproductively sound, commencing lay at a younger age (11.67 ± 3.53 d; P < 0.001), lighter body weight (-169.46 ± 40.20 g; P < 0.001) and with greater intensity (2.68 ± 0.25%; P = 0.001) than the HAS line. Additionally, the LAS line had a greater length of fertility (hens: 2.43 ± 0.55 d; P < 0.001; roosters: 3.11 ± 0.71 d; P < 0.001). In contrast to their poorer reproductive soundness, the HAS line had superior egg quality compared to the LAS line. Egg shape index (4.12 ± 0.55; P < 0.001) and albumen height, measured in both mm (0.27 ± 0.12 mm; P < 0.001) and Haugh units (1.89 ± 0.91; P = 0.04), were superior in HAS hens. Selection for increased antibody response appeared to compromise reproductive soundness, perhaps due to limitations in available resources. However, the selection did not compromise egg quality. / Master of Science

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