Date of Graduation

2015

Document Type

Thesis

Degree Type

MS

College

Davis College of Agriculture, Natural Resources and Design

Department

Animal and Nutritional Sciences

Committee Chair

Joseph S Moritz

Committee Co-Chair

Kenneth Blemings

Committee Member

Janet Tou

Abstract

Improving the crumble/pellet percentage of feed has been argued to be difficult to obtain in the commercial industry due to the necessity of feed mills producing adequate feed volume within a time constraint. Poultry research often utilizes small numbers of birds per pen or experimental unit that may affect the estimation of variance components, potentially producing pen performance metrics that are less valuable for industry guidance. In Experiment 1, diets were manufactured to maintain nutrient availability and vary only in crumble/pellet percentage (standard = 40% pellets, improved = 70% pellets). The two dietary treatments were then fed to Hybrid Converter male turkeys from d 1-126. Growth performance variables were measured and carcass characteristics (breast wt. and yield) were determined. Average pen weight increased by 0.17 kg (P = 0.02) and tended to decrease feed conversion ratio by 11-points (P = 0.07) for toms fed improved quality pellets. Experiment 2, was designed to determine the effects of pen size and crumble/pellet percentage on commercial broiler performance using a 2 (feed quality) x 2 (pen size) factorial treatment arrangement in a randomized complete block design. Feed manufacture was manipulated to maintain nutrient availability constant with treatments differing only in crumble/pellet percentages (standard = 50% pellets, improved = 70% pellets). Growth performance was analyzed at the end of each growth phase (starter d 1-10, grower d 11-21, finisher d 22-38). Carcasses characteristics of hot breast weight and yield were determined on d 38. No interactions were observed for the d1-38 growth period (P > 0.05). Broilers consuming improved crumble/pellet percentage had a tendency towards decreased feed intake (P = 0.07) and feed conversion ratio by 3 points (P = 0.1), but maintained a similar weight gain (P = 0.3). Large pens tended to decrease live weight gain (P = 0.06). Improved (crumble/pellet) percentage increased pen coefficient of variation for within pen ending weight (P = 0.05), likely due to competitive feeding behavior. These experiments suggest that a modest improvement to pellet quality improves both tom turkey and broiler performance, and a small pen model may produce sufficient results for broiler chicken research.

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