Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Animal Science

First Advisor

Robert Thaler


Amino acids, Betaine, Boar, Corn, Growing nursery pigs, Phytase


The quality and effectiveness of the feedstuffs included in diets of production livestock directly impact yield efficiency and performance characteristics desired by producers. This thesis focuses on the performance and digestibility of corn from different countries in pig diets and how different feed additives can be supplemented to improve boar reproductive performance during heat stress. Corn is the largest energy source in common pig diets. The physical characteristics of corn such as broken kernels, foreign material, and excessive dust are said to negatively impact the quality of the grain for pig diets by being less digestible and a worsened nutrient profile. Phytase and betaine are common additives in pig diets to help promote digestibility and nutrient utilization. These products have been included into the diets of boars to help combat one of the swine industry’s most detrimental antagonists to all stages of pig production, heat stress. Three corn sources from the United States, Argentina, and Brazil were utilized in the comparison of corn source and quality in weaned pig diets. The following parameters were measured: growth performance (n=96 mixed sexed pigs), apparent and standardized ileal digestibility (AID and SID) of amino acids (AA) (n=10 barrows), and energetic value of each corn source based on gross energy (GE), digestible energy (DE), metabolizable energy (ME), and net energy (NE) (n=12 barrows). In terms of growth performance characteristics such as final body weight (FBW), average daily gain (ADG), and average daily feed intake (ADFI), no significant differences were detected between nursery pigs fed diets containing corn from the U.S, Brazil, or Argentina. The U.S. cornfed pigs tended to have a greater gain: feed (G: F) ratio compared to those of Brazil and Argentina-fed pigs. In terms of nutrient digestibility, minimal differences were detected between the corn sources. Energy determination (GE, DE, ME, and NE) told a similar story, where minimal differences were detected between grain sources. Mature duroc-influenced boars of mixed ages (n=96) were split into three different barns of identical design, with 32 boars per treatment group, and fed a common diet once per day (NRC, 2012). Room temperature and relative humidity were recorded with LogTags in each barn. Each barn was designated to one of 3 treatment groups receiving a top dress supplement (Control = ground corn and oil; Phytase = ground corn, oil, and a super dose of phytase (2,500 FTU/kg); Phytase +Betaine = ground corn, oil, super dose of phytase (2,500 FTU/kg) + betaine (.60%) for the entire 12-week trial. Phytase and betaine were utilized to determine their ability to help combat the effects of heat stress on reproductive performance through the summer months. All boars were collected once a week and semen was analyzed with an IVOS II, where motility and morphology were recorded. Hand counts of every boar ejaculate were also conducted on weeks 1,3,5,7, and 9 to determine morphology utilizing an IVOS I. Raw semen samples were analyzed at weeks 1, 6, and 12 to determine the levels of inositol in the raw ejaculate, a carbocyclic sugar found in semen that may improve semen characteristics. Minimal differences were detected between boars that were treated with the Control, Phytase, or Phytase + Betaine treatments for nearly all reproductive performance measures that were considered. Hand counted morphology was also not significantly different between the three treatment groups. Inositol levels appeared to be better maintained in the raw ejaculate of the boars that were supplemented with betaine and phytase top-dress compared to the boars that received only the phytase top dress and the control top-dress from week 1 compared to results at found at week 6 and week 12; though these findings were not significantly different.

Library of Congress Subject Headings

Swine -- Feeding and feeds.
Corn as feed.
Amino acids.
Boars -- Reproduction.
Heat -- Physiological effect.
Feed additives.
Swine -- Growth.

Number of Pages



South Dakota State University



Rights Statement

In Copyright