Theses and Dissertations

Issuing Body

Mississippi State University

Advisor

Vizzier-Thaxton, Yvonne

Committee Member

Scanes, Collin

Committee Member

Thaxton, J. Paul

Committee Member

Silva, Juan

Committee Member

Martin, Mike

Other Advisors or Committee Members

Branton, Scott||Schilling, Wes

Date of Degree

1-1-2008

Document Type

Dissertation - Open Access

Major

Food Science, Nutrition and Health Promotion

Degree Name

Doctor of Philosophy

College

College of Agriculture and Life Sciences

Department

Department of Food Science, Nutrition and Health Promotion

Abstract

Molting is a natural occurrence in the Avian species that can include a period of fasting. Animal rights groups view the longepted standard industry practice as inhumane. Based on influences from these groups and the recommendation of its scientific committee, United Egg Producers (UEP) requires members of its Animal Care Certified Program use a noneed withdrawal molting program, even though the morphological and physiological effects of this method have not been studied in depth and the existing literature provides contradictory results. Research regarding how to induce a noneed withdrawal molt has been performed using feed that is nutrient deficient or contains an additive to cease egg production. Studies have shown subsequent egg production to be comparable to hens molted using feed withdrawal. This study was designed to determine the morphological and physiological changes that occur in a noneed withdrawal molt. Two hundred hens divided into 40 groups of 3 birds each were molted in a staggered pattern so that the morphological and physiological effects of noneed withdrawal molt could be measured with identical environmental and housing variables. Data was divided into 5 sections including Control (n=5), Start (n=7), Mid-Molt (n-7), Near End (n=7), and Over (n=15). Internal organs were examined and measured. Corticosterone levels were measured to determine if noneed withdrawal molting causes less stress to hens. Pertinent blood parameters including cholesterol, glucose, O2, CO2, hemoglobin, and hematocrit were also measured. Results indicate internal organ weight changes due to noneed withdrawal molt were as expected. Decreases in the oviduct length, ovary weight, follicle weight, and follicle number indicate regression of the reproductive tract. No differences (P<0.05) were observed in corticosterone levels, suggesting that a noneed withdrawal molt does not increase stress in laying hens.

URI

https://hdl.handle.net/11668/17235

Comments

laying hens||noneed withdrawal molt||stress

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