Date of Award


Degree Type


Degree Name

Master of Science


Animal Science

Major Professor

Michael O. Smith

Committee Members

Brynn Voy, John Waller


In this study, we looked at the effects of supplemental choline or betaine on broiler performance under different temperature conditions. In total there were eighty pens containing ten birds each for a total of 800 Cobb MX™ X Cobb 500™ (Cobb-Vantress, Incorporated, Siloam Springs, AR, USA). Each pen was randomly assigned to one of five dietary treatments in this study: Treatment 1, basal diet, Treatment 2, basal diet plus 500 methyl equivalents added choline, Treatment 3, basal diet plus 1000 methyl equivalents added choline, Treatment 4, basal diet plus 500 methyl equivalents added betaine, and Treatment 5 basal diet plus 1000 methyl equivalents added betaine. The pens were divided equally into two rooms. One room was assigned a treatment classified as thermoneutral (TN) while the second room was designated as high temperature (HT). Dietary treatments did not significantly impact performance (p>0.05), but temperature treatments did have a negative effect on feed intake and feed to gain conversion during days 21 through 42 (p < 0.05). The lack of effect found during this study may have been due to variance in the anticipated feed composition and the actual feed composition. The feed fed during this study contained more methionine, an amino acid known to minimize supplemental choline effects, than what was anticipated. This study showed that high temperatures have a negative impact on performance, and since our dietary treatments were high in methionine, it is still not known whether choline or betaine supplementation, above recommended amounts, to a broiler ration is beneficial or not.

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