Date of Graduation

5-2026

Document Type

Thesis

Degree Name

Bachelor of Science in Agricultural, Food and Life Sciences

Degree Level

Undergraduate

Department

Poultry Science

Advisor/Mentor

Sara Orlowski-Workman

Committee Member

Bryan Kutz

Second Committee Member

Zac Williams

Abstract

            The importance of water conversion ratio in broiler production influences not only bird physiology but also barn environment, litter quality, and provides potential solutions to environmental stressors. However, very little is known about how genetic selection for water conversion ratio can affect litter characteristics and performance parameters, specifically under heat stress conditions. This study evaluates the effects of genetic lines, environmental conditions, and time, on litter and bird performance characteristics in high water conversion ratio (HWCR) and low water conversion ratio (LWCR) broilers. Litter samples were collected from HWCR and LWCR broilers raised under heat-stress and thermal-neutral conditions, both before and after cyclic heat exposure. Samples were analyzed for dry matter percentage, litter pH, nitrogen percentage, and phosphorus and potassium concentrations. Dry matter percentage was greater in LWCR broilers than HWCR broilers. Litter pH differed by genetic line and time, while nitrogen, phosphorus, and potassium concentrations primarily increased over time. Additionally, potassium did exhibit a significant time x environment interaction. Performance parameters, including body weight gain, feed intake, water intake, feed conversion ratio, water conversion ratio, and water-to-feed ratio, were also influenced by genetic line and environmental conditions. HWCR broilers exhibited greater feed and water intake, while heat stress reduced feed intake and body weight gain. Water intake, water conversion ratio, and water-to-feed ratio were all increased when faced with heat stress, while feed conversion ratio was not significantly changed between the treatments. These findings indicate that genetic selection for improved water conversion ratio may influence litter moisture and resource utilization patterns, while nutrient accumulation (N, P, K) largely reflects temporal deposition. Understanding how genetics and environmental conditions interact to shape litter quality may support strategies to improve animal health and welfare, sustainability in broiler production, and environmental stewardship in the face of increasing water scarcity.

Keywords

Water Conversion Ratio; Heat Stress; Litter Quality; Performance Parameters

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