Animal Science, Department of


First Advisor

Dr. Sheila Purdum

Date of this Version

Spring 4-23-2021

Document Type



Foley, Josephine. 2021. The Effects of Different Feed Supplements on Performance Parameters, Egg Measurements, and Eggshell Integrity in Older White Leghorn Laying Hens. Theses and Dissertations in Animal Science.


A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Animal Science, Under the Supervision of Professor Sheila E. Purdum. Lincoln, NE: April, 2021

Copyright © 2021 Josephine N. Foley


Two studies were conducted to evaluate the efficacy of multiple feed additives on the performance of older White Leghorn hens. Study 1 examined the effects of 2 vitamin/mineral supplements and 1 medium chain fatty acid. Study 2 examined the effects of a novel butyric acid product, a tributyrin ester. Both studies followed a completely randomized design with repeated measures and data were analyzed using the Glimmix procedure in SAS version 9.4 for Windows.

The first study took place November 2015 to April 2016. Trt 1 was a control diet, Trt 2 was supplemented with a Ca, Fe, Mn, Cu, Zn mixture, Trt 3 with a medium chain fatty acid, Trt 4 and Trt 5 with a Ca, Vitamin D3, Mn, Zn mixture. A total of 270 Bovan White Leghorn hens were housed in 45 cages. Measurements included: egg production, feed intake, mortality, egg weights, eggshell breaking strength, eggshell percent, and Haugh Unit. Significant differences were seen for feed intake (p<0.0007) and egg weight (p<0.0012). No significant differences were found for egg production (p<0.14), eggshell breaking strength (p<0.1238), eggshell percent (p<0.7974), or Haugh Unit (p<0.6240).

The second study ran from June to September 2016. Trt 1 was fed a control diet and Trt 2 was supplemented with a tributyrin ester at a rate of 0.055%. A total of 144 Bovan White Leghorn hens were housed in 24 cages. Measurements included: mortality, feed intake, egg production, egg weight, egg mass, eggshell percent, eggshell breaking strength, instance of shell deformities, calcium and phosphorus digestibility. No differences were found for feed intake (p<0.9027), egg production (p<0.2857), egg weight (p<0.1346), egg mass (p<0.2618), eggshell percent (p<0.8470), eggshell breaking strength (p<0.0876), instance of shell-less eggs (p<0.2973), calcium digestibility (p<0.9740) or phosphorus digestibility (p<0.2834).

These results show that some improvement can be seen when hens are supplemented with various minerals and fatty acids, with continued research investigating combinations and inclusion rates.

Advisor: Sheila E. Purdum