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Optimizing Animal Welfare In Commercial Laying Hens Through Novel Management Practices And Farm Manager Evaluation, John R. Brunnquell

Theses and Dissertations--Animal and Food Sciences

The commercial production of pasture and free-range eggs in the United States is expanding rapidly. According to the United States Department of Agriculture Agricultural Management Assistance, in May of 2019 there were 2.6M pasture hens and 4.5M free-range hens representing 1.9% of the nation’s laying flock. There is little industry and/or academic experience with this style of production in the United States. Programs such as the European Layer Training Initiative (ELTI), which emerged in 2019, have tried to fill this void but participation from the US was low. The principal sources for guidance of commercial free-range egg production in the …

The Role Of Feed Additives In Mitigating The Effect Of Stressors On Growth, Digestibility, Intestinal Morphology, Permeability, And Immune Response In Poultry, Yemi Olojede Burden

Theses and Dissertations--Animal and Food Sciences

Three experiments were conducted to evaluate the interactive effects of dietary supplements in birds exposed to different stressors, on growth performance, nutrient, and energy digestibility, antioxidant status, intestinal permeability, and immune status. The first study was conducted to evaluate the effect of a commercially available algae-based antioxidant, containing Selenium yeast (EconomasE™, EcoE) and two inorganic sodium sources (NaCl and NaCl+NaHCO3) on growth performance, nutrient and energy digestibility and utilization, antioxidant, and immune status of broilers challenged with oral gavage of dexamethasone (DEX). The inclusion of either of the sodium sources did not affect plasma corticosterone and antioxidant status levels, growth …

The Role Of Melatonin In Biological Rhythms Of Songbirds, Clifford E. Harpole

Theses and Dissertations--Biology

In vertebrates, melatonin is a hormone that is produced and secreted at night and inhibited by light. This unique “darkness-only” expression profile makes it an intellectually appealing candidate for a means of transmitting temporal information to an individual, both time of day and time of year.

In passerine birds, “time of day” information is certainly transmitted via melatonin secretion. The primary producer of systemic melatonin in this family of birds is the pineal gland, and surgical removal of it causes a bird to become arrhythmic in constant conditions. I find that as pinealectomized house sparrows (Passer domesticus) become …